Espresso Barista's Guide to Preparing and Steaming Milk

COMPETENCY BASED LEARNING
MATERIALS
Sector: TOURISM
Qualification Title: BARISTA NC II
Unit of Competency: PREPARE ESPRESSO
Module Title: PREPARING ESPRESSO
QUEZON CITY SKILLS AND LIVELIHOOD FOUNDATION, INC
6 K-F Street, Barangay Kamuning Quezon City

HOW TO USE THIS COMPETENCY- BASED LEARNING MATERIALS
Welcome!
The unit of competency,“Prepare Espresso”, is one of the competencies of “BARISTA NC II”, a course
which comprises the knowledge, skills and attitudes required for a TVET trainer to possess.
The module, “PREPARING ESPRESSO”, contains training materials and activities related to
“PREPARE ESPRESSO “for you to complete.
In this module, you are required to go through a series of learning activities in order to complete each
learning outcome. In each learning outcome are Information Sheets, Self-Checks, Operation Sheets and
Task/Job Sheets. Follow and perform the activities on your own. If you have questions, do not hesitate to
ask for assistance from your facilitator.
Remember to:
• Work through all the information and complete the activities in each section.
• Read information sheets and complete the self-check. Suggested references are included to supplement
the materials provided in this module.
• Most probably, your trainer will also be your supervisor or manager. He is there to support you and
show you the correct way to do things.
• You will be given plenty of opportunities to ask questions and practice on the job. Make sure you
practice your new skills during regular work shifts. This way, you will improve your speed, memory and
your confidence.
• Use the Self-Checks, Operation Sheets or Task or Job Sheets at the end of each section to test your own
progress. Use the Performance Criteria Checklist or Procedural Checklist located after the sheet to check
your own performance.
• When you feel confident that you have had sufficient practice, ask your Trainer to evaluate you. The
results of your assessment will be recorded in your Progress Chart and Accomplishment Chart.
You need to complete this module before you can perform the next module,
“PREPARE AND SERVE COFFEE BEVERAGES”.

BARISTA NC II
COMPETENCY-BASED LEARNING MATERIALS
List of Core Competencies
No. Unit of Competency Module Title Code
1.
Prepare espresso PREPARING ESPRESSO TRS3113100
2.
Texture milk TEXTURING MILK TRS3113101
3.
Prepare and serve
coffee beverages
PREPARING AND
SERVING COFFEE
BEVRAGES
TRS3113102
4.
Perform basic
maintenance of
machine and
equipment
PERFORMING BASIC
MAINTENANCE OF
MACHINE AND
EQUIPMENT
TRS3113103
5.
Perform basic
cashiering and
general control
procedures
PERFORMING BASIC
CASHIERING AND
GENERAL CONTROL
PROCEDURES
TRS3113104

MODULE CONTENT
UNIT OF COMPETENCY : TEXTURE MILK
MODULE TITLE : TEXTURING MILK
MODULE DESCRIPTION : This unit covers the skills and knowledge
required to steam milk which is essential in the preparation of espresso-based
beverages with milk like cappuccino and latte. It covers the two stages of
steaming milk: foaming and heating, at the desired temperature and
consistency.
NOMINAL DURATION : 25 hours
SUMMARY OF LEARNING OUTCOMES:
Upon completion of this module, the trainee/student must be able to:
LO1.Prepare milk and equipment
LO2.Foam milk
LO3.Steam milk
ASSESSMENT CRITERIA:
1. Milk is chilled in accordance to appropriate temperature.
2. Adequate amount of milk is measured according to the kind of drink to
be prepared.
3. Correct (size of ) steaming pitcher is selected in accordance with
enterprise standards
4. Steaming pitcher is chilled in accordance to appropriate temperature.
5. Steam wand is flushed to remove condensed water.
6. Steam wand is wiped before steaming.
7. Rags for the steam wand are kept clean and moist
8. Steam wand is positioned at the right depth of the milk.
9. Full steam is applied when introducing air into the milk.
10. The sound of air being drawn into the milk is judged/evaluated
thru the hissing sound.
11. Milk is stretched according to the desired volume of foam.
12. Milk is converted into microfoam.
13. Steam wand is angled as appropriate to create a whirlpool effect.
14. Milk is spun to achieve the desired consistency
15. Milk is steamed at the ideal temperature for immediate
consumption

16. Steam wand is shut off some 5 degrees before the desired
temperature
17. Steam wand is flushed and wiped after steaming.
18. Big bubbles are removed by swirling and knocking the pitcher on
the counter.

LEARNING OUTCOME 1
PREPARE MILK AND EQUIPMENT
ASSESSMENT CRITERIA:
1. Milk is chilled in accordance to appropriate temperature.
2. Adequate amount of milk is measured according to the kind of drink to
be prepared.
3. Correct (size of ) steaming pitcher is selected in accordance with
enterprise standards
4. Steaming pitcher is chilled in accordance to appropriate temperature.
5. Steam wand is flushed to remove condensed water.
6. Steam wand is wiped before steaming.
7. Rags for the steam wand are kept clean and moist
CONTENTS:
 Types of Milk
 Chemistry of milk
 Milk based coffee beverages
 Milk texturing and steaming
CONDITIONS:
The students/trainees must be provided with the following:
 Learning Tools and Equipment
 Supplies and Materials
 Manuals
 Charts
 Handouts
 References
 IT related and instructional video materials – optional
METHODOLOGIES:
 Modular (self-paced)
 Group discussion
 Self-pace learning

 Role play
 Hands-on
ASSESSMENT METHODS:
 Interview (oral/questionnaire)
 Observation
 Demonstration of Practical Skills
 Written Examination

Learning Experiences
LEARNING OUTCOME 1
PREPARE MILK AND EQUIPMENT
Learning Activities Special Instructions
Read Information Sheet 2.1-1 on Types
of Milk
Read and understand the information
sheet. If you cannot understand the
contents of the information sheet or
any part of it, you may ask assistance
from your facilitator.
Answer Self-Check 2.1-1 Compare answers to Answer Key
2.1-1. You are required to get all
answers correct. If not, read the
information sheets again to answer
all questions correctly.
Listen / Participate in the lecture /
discussion on Types of Milk
Read Information Sheet 2.1-2 on
Chemistry of Milk
Answer Self-Check 2.1-2 Compare answers to Answer Key
2.1-2. You are required to get all
answers correct. If not, read the
information sheets again to answer
all questions correctly.
discussion on Chemistry of Milk
Read Information Sheet 2.1-3 on Milk
Based Coffee Beverages
Answer Self-Check 2.1-3 Compare answers to Answer Key 2.1-
3. You are required to get all answers
correct. If not, read the information
sheets again to answer all questions
correctly.
discussion on Milk Based Coffee

Beverages
Read Information Sheet 2.1-4 on Milk
Texturing and Steaming
Answer Self-Check 2.1-4 Compare answers to Answer Key 2.1-
4. You are required to get all answers
correct. If not, read the information
sheets again to answer all questions
correctly.
discussion on Milk Texturing and
Steaming
Observe the trainer’s demonstration on
Milk Texturing and Steaming
The demonstration of the task shows
the actual procedure on“Milk
Texturing and Steaming”
Perform Task Sheet 2.1-4 on Milk
Texturing and Steaming
Have trainer evaluate performance
using the Performance Criteria
Checklist 2.1-4 Milk Texturing and
Steaming
After doing all activities of this
LO, you are ready to proceed to the
next LO- 2

Information Sheet 2.1-1
Types of Milk
Learning Objectives:
After reading this INFORMATION SHEET YOU MUST be able to:
1. Determine the definition of milk
2. Determine the types of milk
3. Identify the types of dairy milk
4. Identify the types of plant based milk
5. Determine the important considerations if choosing a plant-based
milk
6. Identify its nutritional values
Introduction:
There are many different types of milk available.
The available varieties include numerous types of dairy milk and plant-based
milk options.
This article examines each common variety of milk and its nutritional values.
We will also compare some of the pros and cons of the available options
Definition of Milk
Milk is a fluid secreted by the mammary glands of females for the
nourishment of their young.
Milk from an animal and especially a cow used as food by people.
Milk is a food product produced from seeds or fruit that resembles and is
used similarly to cow's milk.

24 Types of Milk
Types of Dairy Milk
There is a wide range of dairy milk products, including milk of differing fat
levels, flavored milk, and more.
1) Whole Milk
Whole milk refers to minimally adulterated milk that
contains its original fat content.
Since it has a higher fat content than most other milk
products, whole milk also contains more calories.
On the positive side, it has a fuller and creamier taste
than reduced-fat options.
Whole milk is typically 3.25% milk fat within the
United States, but this may change depending on the
country.
2) Reduced Fat Milk (2% Milk)
Reduced-fat milk has a 2% milk fat content.
Outside of the United States, in countries such as the
United Kingdom and
Australia, similar milk products may also take the
name of ‘semi-skimmed milk.’
2% milk contains fewer calories than regular whole
milk, and it tastes more like whole milk than milk options with even lower fat
levels.

3) 1% Milk
As its name may suggest, 1% milk has a milk fat
content of 1%.
As a result, the milk has a less creamy taste and
contains significantly fewer calories.
4) Skim Milk
Skim milk is virtually fat-free and contains significantly
fewer calories than reduced-fat milk options.
As a result, it tends to be an excellent protein source as the
protein to calorie ratio is very high.
However, it has a much more watery consistency than
whole milk, and it does not have a creamy taste. For this
reason, many people find it doesn’t compare well in terms
of taste.
5) Channel Island Milk
Channel Island milk refers to the milk produced by
Jersey and Guernsey cattle breeds.
These breeds were originally from the Channel Islands,
but they now produce milk in countries around the
world.
Compared to milk from cattle that most milk comes
from (Holstein Friesians), whole milk from Jersey and
Guernsey cattle has a higher fat and protein content.

For this reason, the milk has a slightly thicker consistency and a much
creamier taste.
6) Chocolate Milk
While there are many different flavored milk options,
chocolate milk is arguably the most common option.
Interestingly, chocolate milk provides a slightly higher
amount of minerals than regular milk due to its cocoa
content
Although the ingredients can vary, chocolate milk is
usually a combination of dairy milk, cocoa powder,
sugar, and sometimes thickeners.
7) Half and Half
Half and half is a combination of whole milk and cream.
As the name implies, half and half contains 50% whole
milk and 50% cream.
Half and half is often used in the kitchen for making
soups and sauces rather than being for drinking.
The product can be a good compromise when cream is
too heavy, and milk is too light for a particular dish or
usage.
8) Ultra-heat Temperature Milk (UHT)
Ultra-heat temperature milk is regular milk that has
gone through a pasteurization process at an ultra-high
temperature.
According to the International Dairy Foods Association
(IDFA), this temperature must be 138ºC (280ºF) or
above for at least 2.0 seconds .

Notably, UHT-processed milk still has the same nutritional properties as
regular milk. However, it has a much longer shelf-life of approximately 30 to 90
days when refrigerated .
When tested by a trained sensory panel, the panel noted that UHT milk had
“distinct cooked and sulfur flavors” compared with regular milk.
9) Lactose-free Milk
The name of the primary sugar in milk is lactose.
However, much of the world’s population is lactose-
intolerant. This means that regular milk can cause
digestive symptoms in many people
For this reason, lactose-free varieties of milk are
available.
Notably, “lactose-free milk” still contains lactose, but
producers add an enzyme called lactase to it. Lactase is
the enzyme that helps break lactose down, which people
with lactose intolerance do not produce in sufficient
quantities.
Once again, the specific nutritional values of lactose-free milk can differ
depending on the type of milk (whole/skim).
10) Buttermilk
Buttermilk is a drink made from the bacterial fermentation
of milk using a lactic acid-producing culture.
Compared to milk, buttermilk has a thicker consistency
and a slightly sour taste.

11) Evaporated Milk
Evaporated milk is a sweet milk-based drink, often used
with cakes and other desserts.
Despite being sweet, evaporated milk contains no added
sugar or additional ingredients.
Instead, the production process involves heating milk and
letting some of the water content evaporate from it.
The result is that evaporated milk has a thicker
consistency and double the sugar content of regular milk.
Thus, it has a sweeter taste.
Since the water content of evaporated milk is much lower, it also has higher
protein, fat, and calorie levels.
12) Goat Milk
While most commercial milk comes from cattle, goat
milk is a relatively common alternative.
Some people feel there is a difference in taste, with
“grassy” being one common descriptor, but others find
it hard to notice any difference.
13) Milk Powder (Whole Milk)
Milk powder (sometimes known as powdered milk) is
produced from an evaporation process that removes all
the liquid from milk.
Since it has no water content, the remaining milk
powder has a much higher nutrient density.

Milk powder has multiple uses, and it is used in baby formulas, food
production (e.g. milk chocolate), and baking.
14) Milk Powder (Skim Milk)
Compared to whole milk powder, milk powder made
from skim milk has less fat and calories.
Gram-for-gram skim milk powder also contains more
protein and carbohydrate
15) Condensed Milk
The process of making condensed milk is the same as
evaporated milk.
When heating milk, some of the water evaporates, and the
remaining milk becomes more concentrated.
However, condensed milk usually contains large amounts
of added sugar, making it even sweeter
Types of Plant-Based Milk
Plant milk can come from various foods, including grains, nuts, and seeds.
There are dozens of plant milk varieties, but this guide will focus on the most
common options.
1) Almond Milk
Almond milk is the product of almonds and water, and it is
available in sweetened and unsweetened forms.
Some almond milk products are also fortified with
nutrients such as calcium, iodine, vitamin B12, and
vitamin D.

However, this fortification (and the amount) will vary from brand to brand.
Almond milk is the most popular nut-based milk, and it has a light and nutty
taste. It is also probably the lowest calorie variety of milk.
2) Cashew Milk
Cashew milk is a popular plant milk produced from
nuts.
However, the nutrition profile is quite different from
almond milk.
3) Coconut Milk
Coconut milk is slightly different from the
other kinds of plant milk available.
For one thing, it has been available a lot
longer, and it has been a traditional food
ingredient for centuries in South-East Asia.
Additionally, it tends to be used in soups and
curries rather than as a milk alternative. That
said, it can also work in drinks like coffee,
though it has a bold and strong flavor of its
own.
Coconut milk has a high fat content and
provides minimal protein.

4) Hazelnut Milk
Hazelnut milk has significantly lower carbohydrate
content than other nut-based milk products.
Regarding its taste profile, hazelnut milk is very
mild and has a slightly nutty flavor.
5) Hemp Milk
Hemp milk is a relatively new but popular plant milk
option.
Despite being a seed, milk made from hemp tends to
have a nutty taste similar to other kinds of nut milk.
The flavor is mild, and it has a thicker/creamier
consistency than many plant milk options.
While the protein content of hemp milk doesn’t quite
match dairy milk, it is higher than other nut milk
varieties.
6) Oat Milk
Oat milk is the most popular type of milk produced from
grains.
Also, it is the second most popular plant-based milk in
the United States after almond milk.
Oat milk has a medium-thick consistency, but it is not as
thick or creamy as whole dairy milk.
It has a light, oaty, and somewhat nutty taste, and it is
lower in fat and higher in carbohydrate than many kinds of plant milk.

7) Pea Milk
Unlike many types of plant-based milk, pea milk is a
rich source of protein.
8) Rice Milk
Rice milk is relatively bland and mild and has no
strong flavors.
However, it has a mild sweetness due to its high
carbohydrate content.
Rice milk contains very low amounts of protein and
fat.
9) Soy Milk
Soy milk is one of the oldest plant-based milk varieties
and one of the most popular.
In the United States, it is the third most popular plant-
based milk behind almond milk and oat milk.
Soy milk has a mildly sweet flavor, and many people
seem to enjoy the taste.

Important Considerations if Choosing Plant-Based Milk
Here are some crucial points to consider if opting for plant-based milk.
Various plant milks are on the market and they are designed to mimic the
appearance and uses of dairy milk. However, they are not always comparable
nutritionally.
Most plant milks offer a lot less protein than dairy milk. If protein is important,
soy milk and pea milk are the best plant-based options.
Dairy milk contains a wide variety of nutrients, including calcium, iodine,
vitamin B12, and vitamin D. Not all plant milk options will provide equivalent
amounts of these important nutrients – check the package label as it will vary
from brand to brand.
Nutritional Values
Types of Dairy Milk
1) Whole Milk
Here are the nutritional values for a regular 246-gram cup of whole milk:
 Calories: 149 kcal
 Carbohydrate: 11.7g
 Sugars: 11.7g
 Fat: 7.98g
 Saturated fat: 4.54g
 Monounsaturated fat: 1.98g
 Polyunsaturated fat: 0.47g
 Protein: 7.69g
 Protein per 100 calories: 5.16 grams

2) Reduced Fat Milk (2% Milk)
Per 245-gram glass serving, reduced-fat milk provides the following nutritional
values:
 Sugars: 12.2g
 Fat: 4.7g
 Protein: 8.53g
3) 1% Milk
A regular 245-gram cup of 1% milk has the following nutritional properties:
 Sugars: 12.2g
 Fat: 2.38g
 Protein: 8.53g
 Protein per 100 calories: 8.12 gram
4) Skim Milk
The nutritional values per 245-gram cup of skim milk are as below:
 Sugars: 12.2g
 Fat: 0.2g
 Protein: 8.26g
5) Channel Island Milk
One 245-ml cup of Channel Island milk will offer the following nutritional
values:
 Sugars: 11.27g

 Fat: 12.25g
 Protein: 9.8g
6) Chocolate Milk
A 250-ml cup of chocolate milk offers these nutritional values:
 Sugars: 23.8g
 Fat: 8.48g
 Protein: 7.92g
 Protein per 100 calories: 3.81
grams
7) Half and Half
A regular 242-gram cup of half and half has the following nutritional profile:
 Sugars: 10g
 Fat: 27.8g
 Protein: 7.58g
8) Ultra-heat Temperature Milk (UHT)
The nutritional profile of UHT milk will depend on the type (whole/reduced
fat/fat-free) of milk.
9) Lactose-free Milk
That said, here are the nutritional values of lactose-free whole milk per 244-
gram cup:
 Sugars: 11.7g
 Fat: 7.81g

 Protein: 8g
10) Buttermilk
Here are the nutritional properties for buttermilk made from whole milk, per
245-gram cup:
 Carbohydrate: 12g
 Sugars: 12g
 Fat: 8.11g
 Protein: 7.86g
11) Evaporated Milk
A 252-gram of evaporated milk provides the following nutritional values.
 Sugars: 25.2g
 Fat: 19.1g
 Protein: 17.2g
12) Goat Milk
The nutritional differences are minimal, too; the values per 244-gram cup of
whole goat milk are below:
 Sugars: 10.9g
 Fat: 10.1g
 Protein: 8.69g

13) Milk Powder (Whole Milk)
Per 100 grams, whole milk powder has the following nutritional profile:
 Sugars: 49g
 Fat: 5.78g
 Protein: 34.3g
14) Milk Powder (Skim Milk)
Here are the nutritional values per 100 grams
of skim milk powder:
 Sugars: 52g
 Fat: 0g
 Saturated fat: 0g
 Protein: 36g
15) Condensed Milk
A typical 304-gram cup of condensed milk has the following nutritional values :
 Sugars: 165g
 Fat: 26.4g
 Protein: 24g

Types of Plant-Based Milk
1) Almond Milk
According to the USDA FoodData Central nutrition database, a 244-gram cup
of unsweetened almond milk provides:
 Sugars: 1.98g
 Fat: 2.34g
 Protein: 0.98g
2) Cashew Milk
Here are the nutritional values for a 240-ml cup of unsweetened cashew milk:
 Sugars: 1.01g
 Fat: 10g
 Protein: 4.01g
As shown, cashew milk has similar calories as whole dairy milk. However, it
contains more fat and fewer carbohydrates and protein.
3) Coconut Milk
Per 244-gram cup, coconut milk has these nutritional values:
 Sugars: 6.1g

 Fat: 5.08g
 Monounsaturated fat: 0g
 Polyunsaturated fat: 0g
 Protein: 0.51g
4) Hazelnut Milk
Per 240-ml cup, the nutritional values for unsweetened hazelnut milk are as
follows:
 Sugars: 6.1g
 Fat: 9g
 Monounsaturated fat: 0g
 Polyunsaturated fat: 0g
 Protein: 1.99g
5) Hemp Milk
A 257-gram cup serving of hemp milk has the following nutrition profile:
 Sugars: 6.2g
 Fat: 6.8g
 Protein: 4.4g
6) Oat Milk
A typical 240-ml cup serving of unsweetened oat milk has the following
nutrition profile:
 Sugars: 1.01g
 Fat: 1.49g
 Protein: 4.01g

7) Pea Milk
An unsweetened 240-ml cup of pea milk has the following nutrition profile:
 Sugars: 0g
 Fat: 4.51g
 Protein: 7.99g
8) Rice Milk
Here is the nutritional profile for one 240-ml cup of unsweetened rice milk:
 Sugars: 12.7g
 Fat: 2.33g
 Protein: 0.67g
 Protein per 100 calories: 0.59
grams
9) Soy Milk
Here are the nutritional values for a 240-gram cup of unsweetened soy milk:
 Sugars: 1.34g
 Fat: 5.09g
 Protein: 8.52g

Self- Check 2.1-1
Types of Milk
Multiple Choice: Choose the correct letter or answer.
1. It refers to minimally adulterated milk that contains its original fat
content.
a. Reduced Fat Milk
b. Whole Milk
c. 1 % Milk
d. Skim Milk
2. It has 2% milk fat content.
a. Reduced Fat Milk
b. Whole Milk
c. 1 % Milk
d. Skim Milk
3. It has a milk fat content of 1%.
a. Reduced Fat Milk
b. Whole Milk
c. 1 % Milk
d. Skim Milk
4. It is virtually fat-free and contains significantly fewer calories than
reduced-fat milk options.
a. Reduced Fat Milk
b. Whole Milk
c. 1 % Milk
d. Skim Milk
5. It is the product of almonds and water, and it is available in sweetened
and unsweetened forms.
a. Coconut Milk
b. Almond Milk
c. Cashew Milk
d. Hazelnut Milk

6. It has significantly lower carbohydrate content than other nut-based milk
products.
a. Coconut Milk
b. Almond Milk
c. Cashew Milk
d. Hazelnut Milk
7. It is slightly different from the other kinds of plant milk available.
a. Coconut Milk
b. Almond Milk
c. Cashew Milk
d. Hazelnut Milk
8. It is popular plant milk produced from nuts.
a. Coconut Milk
b. Almond Milk
c. Cashew Milk
d. Hazelnut Milk

Answer Key 2.1-1
Types of Milk
1. B
2. A
3. C
4. D
5. B
6. D
7. A
8. C

Chemistry of Milk
1. Analyze the basic chemical concepts
2. Determine the basic physical chemical properties of cow’s milk
3. Determine the acidity of solutions
4. Identify the composition of cow’s milk
Introduction:
The principal constituents of milk are water, fat, proteins, lactose (milk sugar)
and minerals (salts). Milk also contains trace amounts of other substances
such as pigments, enzymes, vitamins, phospholipids (substances with fatlike
properties), and gases.
The residue left when water and gases are removed is called the dry matter
(DM) or total solids content of the milk.
Milk is a very complex product. In order to describe the various constituents of
milk and how they are affected by the various stages of treatment in the dairy,
it is necessary to resort to chemical terminology. This chapter on the chemistry
of milk therefore begins with a brief review of some basic chemical concepts.
Chemical symbols of some common elements in organic matter:
C - Carbon
Cl -Chlorine
H - Hydrogen
I - Iodine
K -Potassium
N - Nitrogen
Na - Sodium
O- Oxygen
P- Phosphorus
S - Sulphur

BASIC CHEMICAL CONCEPTS
ATOMS
The atom is the smallest building block of all matter in nature and cannot be
divided chemically. A substance in which all the atoms are of the same kind is
called an element. More than 100 elements are known today. Examples are
oxygen, carbon, copper, hydrogen and iron. However, most naturally-occurring
substances are composed of several different elements. Air, for example, is a
mixture of oxygen, nitrogen, carbon dioxide and rare gases, while water is a
chemical compound of the elements hydrogen and oxygen.
The nucleus of the atom consists of protons and neutrons, Figure 2.1. The
protons carry a positive unit charge, while the neutrons are electrically neutral.
The electrons, which orbit the nucleus, carry a negative charge equal and
opposite to the unit charge of the protons.
An atom contains equal numbers of protons and electrons with an equal
number of positive and negative charges. The atom is therefore electrically
neutral.
An atom is very small, Figure 2.2. There are about as many atoms in a small
copper coin as there are seconds in a thousand million million years! Even so,
an atom consists mostly of empty space. If we call the diameter of the nucleus
one, the diameter of the whole atom is about 10 000.
Fig. 2.1
The nucleus of the atom consists of protons and
neutrons. Electrons orbit the nucleus.
Fig. 2.2
The nucleus is so small in relation to the atom that
if it were enlarged to the size of a tennis ball, the outer
electron shell would be 325 metres from the centre.

IONS
An atom may lose or gain one or more electrons. Such an atom is no longer
electrically neutral. It is called an ion. If the ion contains more electrons than
protons it is negatively charged, but if it has lost one or more electrons it is
positively charged.
Positive and negative ions are always present at the same time; i.e. in solutions
as cations (positive charge) and anions (negative charge) or in solid form as
salts. Common salt consists of sodium (Na) and chlorine (Cl) ions and has the
formula NaCl (sodium chloride).
MOLECULES
Atoms of the same element or of different elements can combine into larger
units, which are called molecules. The molecules can then form solid
substances, e.g. iron (Fe) or siliceous sand (SiO2), liquids, e.g. water (H2O), or
gases, e.g. hydrogen (H2). If the molecule consists mainly of carbon (C),
hydrogen (H2) and oxygen (O2) atoms, the compound formed is said to be
organic, i.e. produced from organic elements. An example is lactic acid
(C3H603). The formula means that the molecule is made up of three carbon
atoms, six hydrogen atoms and three oxygen atoms.
The number of atoms in a molecule can vary enormously. There are molecules
which consist of two linked atoms, and others composed of hundreds of atoms.
Fig 2.3
Three ways of symbolizing a water molecule Fig 2.4Three ways of symbolizing an ethyl
alcohol molecule

BASIC PHYSICAL CHEMICAL PROPERTIES OF COWS’ MILK
Cows’ milk consists of about 87 % water and 13 % dry substance, table 2.1.
The dry substance is suspended or dissolved in the water. Depending on the
type of solids and size of particle (table 2.2), there are different distribution
systems of them in the water phase.
Table 2.1
Physical-chemical status of cows’ milk.
Average
composition
%
Emulsion
type
oil/water
Colloidal
solution/
suspension
True
solution
Moisture 87,5
Fat 3,9 X
Proteins 3,4 X
Lactose 4,8 X
Minerals
(Ash) 0,8 X
Organic compounds contain mainly carbon, oxygen and hydrogen. Inorganic
compounds contain mainly other atoms.
Table 2.2
Relative sizes of particles in milk.
Size (mm) Type of particles
10-2 to 10-3 Fat globules
10-4 to 10-5 Casein-calcium phosphates
10-5 to 10-6 Whey proteins
10-6 to 10-7 Lactose, salts and other substances in true solutions

DEFINITIONS
Emulsion: a suspension of droplets of one liquid in another. Milk is an
emulsion of oil in water (o/w), butter an emulsion of water in oil (w/o), Figure
2.5. The finely divided liquid is known as the dispersed phase and the other as
the continuous phase.
Collodial solution: when matter exists in a state of division intermediate to true
solution (e.g. sugar in water) and suspension (e.g. chalk in water) it is said to
be in colloidal solution or colloidal suspension.
The typical characteristics of a colloid are:
 Small particle size
 Electrical charge and
 Affinity of the particles for water molecules
Substances such as salts destabilize colloidal systems by changing the water
binding and thereby reducing protein solubility. Factors such as heat cause
unfolding of the whey proteins and increased interaction between the proteins
and alcohol may dehydrate the particles.
True solutions: Matter which, when mixed with water or other liquids, forms
true solutions, is divided into:
 Non-ionic solutions. When lactose is dissolved in water, no important changes
occur in the molecular structure of the lactose.
 Ionic solutions. When common salt is dissolved in water, cations (Na+) and
anions (Cl–) are dispersed in the water, forming an electrolyte, Figure 2.7.
Fig 2.5
When milk and cream turn to butter, there is a phase inversion from an oil-
in-water emulsion to a water-in-oil emulsion.
Fg 2.6Milk proteins can be made visible by an electron microscope

ACIDITY OF SOLUTIONS
When an acid (e.g. hydrochloric acid, HCl) is mixed with water it releases
hydrogen ions (protons) with a positive charge (H+). These quickly attach
themselves to water molecules, forming hydrogen (H30+) ions.
When a base (a metal oxide or hydroxide) is added to water, it forms a basic or
alkaline solution. When the base dissolves it releases hydroxide (OH–) ions.
 A solution that contains equal numbers of hydroxide and hydrogen ions is
neutral. Figure 2.8.
 A solution that contains more hydroxide ions than hydrogen ions is alkaline.
Figure 2.9.
 A solution that contains more hydrogen ions than hydroxide ions is acid.
Figure 2.10
Fig 2.7
Ionic solution Fig 2.9
Alkaline solution
with pH higher than 7
Fig 2.8
Neutral solution with pH Fig 2.10
Acid solution with pH
less than 7

PH
The acidity of a solution is determined as the concentration of hydrogen ions.
However, this varies a great deal from one solution to another. The symbol pH
is used to denote the hydrogen ion concentration.
Mathematically, pH is defined as the negative logarithm to the base 10 of the
hydrogen ion concentration expressed in molarity, i.e. pH = – log [H+]. This
results in the following scale at 25 °C:
pH > 7 – alkaline solution
pH = 7 – neutral solution
pH < 7 – acid solution
NEUTRALIZATION
When an acid is mixed with an alkali the hydrogen and hydroxide ions react
with each other to form water. If the acid and alkali are mixed in certain
proportions, the resulting mixture will be neutral, with no excess of either
hydrogen or hydroxide ions and with a pH of 7. This operation is called
neutralization and the chemical formula:
H30+ + OH- results in H20 + H2O
Neutralization results in the formation of a salt. When hydrochloric acid (HCl)
is mixed with sodium hydroxide (NaOH), the two react to form sodium chloride
(NaCl) and water (H20). The salts of hydrochloric acid are called chlorides, and
other salts are similarly named after the acids from which they are formed:
citric acid forms citrates, nitric acid forms nitrates, and so on.
DIFFUSION
The particles present in a solution – ions, molecules or colloids – are influenced
by forces which cause them to migrate (diffuse) from areas of high
concentration to areas of low concentration. The diffusion process continues
until the whole solution is homogeneous, with the same concentration
throughout.
Sugar dissolving in a cup of coffee is an example of diffusion. The sugar
dissolves quickly in the hot drink, and the sugar molecules diffuse until they
are uniformly distributed in the drink.
The rate of diffusion depends on particle velocity, which in turn depends on the
temperature, the size of the particles, and the difference in concentration
between various parts of the solution.
Figure 2.11 illustrates the principle of the diffusion process. The U-tube is

divided into two compartments by a permeable membrane. The left leg is then
filled with water and the right with a sugar solution whose molecules can pass
through the membrane. After a while, through diffusion, the concentration is
equalized on both sides of the membrane.
Fig 2.11
The sugar molecules diffuse through the permeable membrane and the water molecules
diffuse in the opposite direction in order to equalize the concentration of the solution.
OSMOSIS
Osmosis is the term used to describe the spontaneous flow of pure water into
an aqueous solution, or from a less to a more concentrated solution, when
separated by a suitable membrane. The phenomenon of osmosis can be
illustrated by the example shown in Figure 2.12. The U-tubes are divided in
two compartments by a semi-permeable membrane. The left leg is filled with
water and the right with a sugar solution whose molecules cannot pass
through the membrane. Now the water molecules will diffuse through the
membrane into the sugar solution and dilute it to a lower concentration. This
process is called osmosis.
The volume of the sugar solution increases when it is diluted. The surface of
the solution rises as shown in Figure 2.12, and the hydrostatic pressure, a, of
the solution on the membrane becomes higher than the pressure of the water
on the other side. In this state of imbalance, water molecules begin to diffuse
back in the opposite direction under the influence of the higher hydrostatic
pressure in the solution.
When the diffusion of water in both directions is equal, the system is in
equilibrium. If hydrostatic pressure is initially applied to the sugar solution,
the intake of water through the membrane can be reduced. The hydrostatic
pressure necessary to prevent equalization of the concentration by diffusion of
water into the sugar solution is called the osmotic pressure of the solution

Fig. 2.12
The sugar molecules are too large to diffuse through the semi-permeable
membrane. Only the small water molecules can diffuse to equalize the concentration. “a”
is the osmotic pressure of the solutio
REVERSE OSMOSIS
If a pressure higher than the osmotic pressure is applied to the sugar solution,
water molecules can be made to diffuse from the solution to the water, thereby
increasing the concentration of the solution. This process illustrated in Figure
2.13 is used commercially to concentrate solutions and is termed Reverse
Osmosis (RO).
Fig. 2.13
If a pressure higher than the osmotic pressure is applied to the sugar solution, water
molecules diffuse and the solution becomes more concentrated
DIALYSIS
Dialysis is a technique employing the difference in concentration as a driving
force to separate large particles from small ones in a solution, for example
proteins from salts. The solution to be treated is placed on one side of a
membrane, and a solvent (water) on the other side. The membrane has pores of
a diameter which allows the small salt molecules to pass through, but is too
small for the protein molecules to pass, see Figure 2.14.
The rate of diffusion varies with the difference in concentration, so dialysis can
be speeded up if the solvent on the other side of the membrane is changed
often.

Fig 2.14
Diluting the solution on one side of the membrane concentrates the large molecules as
small molecules pass through it
Cow Milk: Composition and Properties.
This product is familiar to every inhabitant of our planet. Traditionally, milk is
used for food by children and adults. Scientists frighten us with arguments
about its harmful properties, but fans of this product does not become less.
This is due to the fact that milk is unique in its composition and properties, a
natural product. In addition, it is raw materials for the production of a huge
number of food products, which we use with great pleasure and health
benefits. Let's study in this article in more detail cow's milk, composition and
its useful properties.
MILK - ALMOST 90% WATER?
For many, this fact is surprising, but the milk really is 87.5% water. All other
amazing and useful components are concentrated in 12.5% of dry matter.
This was determined by standard drying the milk sample to constant weight at
a temperature of 105 ° C. As a result of this process, the water is completely
evaporated, and only dry substances remain.

But the liquid consistency of milk is due not to a large amount of water, but to
the fact that all substances and compounds are in a dissolved state.
Milk is also characterized by the SOMO index (dry fat-free milk residue). This
value is obtained if all milk and water is removed from the milk. This indicator
is normally at least 9% and serves as an indicator of the quality of the natural
product. Cow's milk, whose composition was depleted by dilution with water,
will give the SOMO index much lower than the norm.
IS MILK FAT USEFUL?
The milk fat content of cow's milk is 3.5% on average. This indicator is strictly
controlled by farmers and receivers of raw materials in factories. It is this
characteristic that affects the quality of products: sour cream, cream, cottage
cheese.
The composition of milk fat includes about 20 fatty acids. It is characterized by
a low melting point (25-30 ° C) and freezing (17-28 ° C). The peculiarity of this
fat is its shallow teardrop-shaped structure in the composition of milk.
Self- Check 1.1-2
Types of Commercially Viable Coffee Beans
Multiple Choice: Choose the correct letter or answer
1. It is well-known in coffee industry for its higher quality beans,
having a more complex, acidic, and sweet flavor.
a. Robusta
b. Excelsa
c. Arabica
d. Liberica

2. It is the only one that has unique characteristics.
a. Robusta
b. Excelsa
c. Arabica
d. Liberica
3. Its beans have a fruity, lingering taste which is known for its unique
and complex aroma.
a. Robusta
b. Excelsa
c. Arabica
d. Liberica
4. It is considered to have a low-grade bean.
a. Robusta
b. Excelsa
c. Arabica
d. Liberica
5. This coffee comes from the digested Coffee beans which a Civet cat eats.
a. Kopi Uwak
b. Kopi Luwak
c. Black Ivory Coffee
d. Ivory Coffee
Answer Key 1.1-2
Types of Commercially Viable Coffee Beans
1. C
2. D
3. B
4. A
5. B

Roast Levels
1. Know the meaning of roast level in coffee
2. Know the why does coffee need to be roasted
3. Learn about the processing of coffee
Introduction:
Roasting levels in coffee vary from brand to brand, and I'm pretty sure
they're not very well explained on the back of coffee packs.

This leads to people not knowing what they're buying, and lots of confusion
as to what roast level is best, or even if there is such a thing.
Coffee Roast Level
What does roast level mean in coffee?
A roast level in coffee is the point at which the coffee roaster was stopped,
leading the coffee beans to a certain state.
This means the coffee beans may have cracked for the first time, or just
before the first time, they may have released most of their natural oils, and
so on.
You're going to find all sorts of coffee roast levels printed on the coffee you
buy. They range from light to dark, and contain everything in between. Often
they've got names that have nothing to do with the color or actual degree of
roasting.
In general, lighter roasts are lighter in body, more watery, but also have a
more specific flavor.
Darker roasts have more body to them, but a rather bland and simple flavor.
Why does coffee need to be roasted ?
We need our coffee roasted because we can't consume it otherwise. Fresh
coffee beans are inedible and undrinkable and would not offer an acceptable
brew.
This means that the coffee beans must be roasted, at least a little, so we can
properly make a cup of coffee. The preferred level of coffee roasting will vary
from person to person, and as such opinions are very mixed.

But we can at least all agree that coffee does need roasting. Otherwise it has
no flavor, much like tea leaves.
Coffee's journey from fresh bean to brewed cup
Just before we get right into the actual coffee bean roasting, let's take a
quick look at how the beans go from fresh to brewed. This is so you get a
clearer picture of what's happening with the beans, and your coffee in
general.
Once the coffee cherries are picked, and the pits removed (the beans
themselves) they are green. They're first dried, and left to sit at room
temperature.
Once dry, the coffee beans are then transferred to an industrial oven (in the
case of large coffee companies), and they are slowly roasted.
As the beans roast, they crack since they expand in size. It sounds a lot like
popcorn, some beans starting sooner and some later. The cracks are
important, and there a few that you need to be aware of.
The temperature at which the beans are roasted, as well as the total amount
of time they spend in the oven all contribute to the final roasting level.
In short, the longer and hotter the roast, the darker/higher the roast level.

Most of the coffee you find on the shelves in supermarkets are medium,
medium-dark, some even just dark roasts.
This is because when roasting in large batches, it's fairly hard to control
each bean's roast level, and it's easier to let all the beans reach a darker
roast than stop the oven too early and end up with very uneven beans.
Now that we've figured that, let's talk about the actual roast levels, one by
one. These are the main ones, but you'll find some companies roasting their
coffees somewhere in between these levels.
1. Light roasts are the first step
These are the first acceptable coffee beans that come out of the roasting
oven, but are not often found in stores. They're somewhere from the
beginning to the middle of the first crack of the coffee beans.
Usually this means that your coffee is starting to smell like actual coffee.
Before, as it was reaching this point, there was a very grassy/hay smell to
them.

Now they're beginning to smell more like roast coffee, and they have a nice,
milk coffee color to them. These are also what some people call Blonde
roasts, New England Roasts, Light City Roast, American Roast, Cinnamon
Roast.
Your oven should be around 405 F/207 C, and your coffee beans will not
have a sheen of oil on them yet.
This kind of coffee can sometimes be found in supermarkets, though it's not
very common. When you do get your hands on such a roast, you can taste
the origin of the coffee beans.
Meaning, if there are any fruity, or honey, or wine notes to your coffee
beans, you'll be able to detect them here. Darker roasts tend to mute the
specific notes of coffee.
Also, this coffee is going to be more acidic in taste, and have less body to it
than a medium roast.
If you were to drink this coffee black, it wouldn't be the best, but it would
show you the origin of the coffee best.
Recently, w
e've come to know of white coffee. This is lighter than light roast, and as
such does not have the typical look, smell or flavor of coffee. They're pulled
out of the roaster just before the first crack starts.
Instead it's a rather nutty, earthy kind of flavor, and it brews a pale, murky
amber color, as opposed to regular coffee's dark brown color.
It's not a common coffee type, and still more of a gourmet thing.
2. Medium-light keeps more of the origin flavor
The next step is to roast the beans to medium-light. This roast level keeps
less of the origin flavor than a pure light roast, but more than a medium.
Your coffee will have a little more body to it than a light roast, when brewed.
It's still not going to have any coffee oils on the surface, and the first crack
has come and gone.

Right now, you need to know we're between the end of the first crack, and
the beginning of the second one. Some beans may start cracking now, but
only a few.
This is also know as a City Roast, or a City Roast Plus, depending on where
you're from.
Your oven will be at a 425 F/220 C, and the smell of roast will be more
pronounced.
This roast is more common than light roast in, and is better tasting.
3. Medium is the most common roast, and the most balanced
The most common roast level and the best that history
has decided.
Medium roasts offer a great balance between origin
flavors, body, and roast taste.
The coffee is the most flavorful and satisfying at this
point, and will shine best in French press or pour-over
coffee.
Your oven should be at 435 F/223 C, and your coffee
beans should have a hint of coffee oil on them.
The beans should be just at the beginning of the 2nd crack, and barely
getting into the half of it.

The roast smell will be more pronounced, and you might even see a bit of
smoke coming out of the oven. That's normal, as the beans dry out and the
oil comes to the surface.
Another name for medium roast is Full City roast, and Full City Roast Plus.
The Plus goes a little into medium-dark territory.
4. Medium-dark is a little stronger tasting
This is the middle of the 2nd crack, and the coffee
beans will be clearly oily. There will be more smoke, and
you will need to act quickly if you want to stop your
roasting process here.
The oven will be at 440 F/226 C, and the taste of 'roast'
will be overshadowing the actual flavor of the coffee by
this point.
Not much of the origin of the beans will be left, meaning you could throw
any ol' coffee bean in the oven and have it taste almost the same with this
roast.
The beans will be a very dark brown by this point. If you want a name, this
is also known as Vienna roast.
5. Dark roasts hide most of the flavor
The darker we go, the less flavor we get. More of the
burnt and roast flavor will be present, which also
means that the beans will start to lose their quality,
no matter how they started.
This is pretty much any roast past 445 F/229 C, also
known as French/Italian/Spanish roast.
The 2nd crack is tapering off or has already stopped. If you let it run a bit
more, you might hear the beginning of the 3rd crack, but no one is meant to go
that far.

Now, this roast is going to be very 'thin' tasting, in that most of the coffee's
body will be burnt away, and this is evident when drinking a cup of coffee
brewed from these beans.
The color will be nearly black, possibly turning greyish in some cases.
The Processing of Coffee
Dry Method
- The oldest, most natural, and cheapest.
- The fruits either dry on the tree or the tree is shaken or
stripped.
- The ripe and unripe fruits are spread out, dried and shriveled
under the sun.
- passes through a hulling-machine to separate the skin from the
beans
Wet Method
-The beans are handpicked; fully ripened, quality beans.
-The beans are washed and water is gently sprayed over them to
remove the pulp and any debris.
-Dried in the sun and also passes through a hulling-machine to
separate the skin from the beans.
Sorting of Coffee
Mechanical Process
- Beans are sorted by size and weight using a motorized sleeve-like with
different hole sizes

Hand Process
- People sort the beans by hand by size and weight.
Self- Check 1.1-3
Roast Levels
1. It is the oldest, most natural, and cheapest processing of
coffee.
a. Dry Method
b. Wet Method
c. Both a and b
d. None of the above

2. It is a process were the beans are handpicked; fully ripened,
quality beans.
a. Dry Method
b. Wet Method
c. Both a and b
3. It is where the fruits are either dry on the tree or the tree is shaken or
stripped.
a. Dry Method
b. Wet Method
c. Both a and b
4. It is where the beans are washed and water is gently sprayed over them
to remove the pulp and any debris.
a. Dry Method
b. Wet Method
c. Both a and b
5. It is where the ripe and unripe fruits are spread out, dried and shriveled
under the sun.
a. Dry Method
b. Wet Method
c. Both a and b
Answer Key 1.1-3
Roast Levels
1. A
2. B
3. A
4. B
5. A

Espresso Extraction
1. Know the meaning of coffee extraction
2. Know the meaning of espresso brewing
3. Know the meaning of extraction
4. Learn the difference of over-extraction and under-extraction
5. Know about grind size and extraction
6. Learn about espresso extraction and coffee brewing temperature

7. Learn about brew time
Introduction:
If you are interested in perfecting your espresso making skills and technique,
you need to understand the science behind it. The science behind espresso
brewing is called extraction.
Meaning of Coffee Extraction
Coffee extraction is the process of dissolving ground coffee in water
This chemistry concept is important in coffee brewing because it
determines how good your coffee is.
Meaning of Espresso Brewing
Espresso brewing is particularly interesting, because the espresso extraction is
more complex than other brewing methods.
Pressure during extraction changes the extraction, creating the unique flavor
profile of espresso.
In this article we are going to explore how different brewing variables affect
extraction, and how will these affect flavor in the cup.
Espresso Brewing Variables
The most important factors that affect the
extraction rate are: brew temperature, exposure
time, (brew time), amount of coffee, (dose), and
the particle size, (grind size). In espresso we also
have pressure, which is unique to to this
brewing method.
These brewing variables are all interdependent,
and together they are responsible for the perfect

extraction. When one variable is changed, everything else is affected.
IMPORTANT: Follow a recipe that produces coffee that you like, master this
recipe first, and only the start tweaking it to improve it. If you start a recipe
from scratch, you will have too many things to adjust until you get it right.
Brewing Variables that We don’t Touch
Well, if they are variables we should be able to tweak them, right? Yes and no.
If you are a mad scientist that wants to create a new way to brew espresso, yes.
Tweak all the variables you want. But if you want to get a great espresso with
the least effort, then stick to what’s important.
From practical perspective, pressure, tamping force, and dose are fixed when
playing with brewing variables.
The extraction time is something that can be easily adjusted, but you should
not play with it, and you’ll see why in a bit.
Pressure is normalized at 9 bars on the vast majority of espresso machines.
There is no way barista can change this on a normal espresso machine.
The dose is dictated by the filter-basket size. While small 0.5 to 1 gram
adjustments are possible, it is not recommended because the space between
the shower and the coffee puck, (head space), determines the extraction.
Tamping force is something many experienced baristas play with. While is not
inherently bad to play with, I found that sticking to the same tamping pressure
makes it easier to perfect your shots.
The last factor that we should not play with is extraction time. There are too
many bad shots pulled because of the extraction time. The perfect extraction
time for an espresso is 20 to 25 seconds. No matter if it’s a lungo, a doppio, a
ristretto, or a triple shot.
The barista should tweak all other factors in order to get a shot pulled for 25
seconds.
The problem is that the inexperienced barista will try to correct a badly
configured shot by adjusting the extraction time. The most common example is
increasing the extraction time to compensate for a too restricted shot.
If a shot is too restricted, we should adjust the grind size, and not the extraction
time.

Brewing Variables that We Play with
The two most important variables in espresso brewing are the grind size and
the water temperature.
I know that some baristas will disagree on the brew temperature, but stick with
me and you’ll see why sometimes you need to change the brew temperature, for
amazing shots.
OK, we need to mention roast degree and origin. You will have to take these in
consideration when pulling your shots. Roast level is in fact so important that
will decide the two other brew variables that you can play with: grind size and
water temperature.
Before explaining how temperature and grind size affect extraction, lets review
the coffee extraction definition.
What Is Extraction?
Extraction is the process that pulls flavors from coffee
grounds into the water. Extraction is affected by many
factors, including brew time, water temperature, grind
size, roast level. Coffee extraction is based on the
chemical property of coffee solubility.
A lot of the compounds in coffee are soluble in water. It’s like sugar or table
salt. You put them in water and they will dissolve. However, these compounds
dissolve faster or slower in water. Some of these compounds only dissolve at
high temperatures, and some are volatile, so they dissipate at higher
temperatures.
Coffee beans are about 28% water-soluble. This is how much you can get out of
the whole roasted coffee bean into your cup. The rest of the coffee bean’s
structure is made of cellulose and plant stuff. This doesn’t mean we want to
extract all of the 28%, some of that stuff tastes nasty.
Espresso extraction is a process that is
optimized to dissolve in water the maximum

amount of desirable compounds, while minimizing the amount of undesirable
elements.
Here is a list with most of the brew variables that affect extraction.
 Grind size
 Brew temperature
 Pressure
 Tamping force
 Dose, (amount of coffee grounds used per brewed cup)
 Coffee beans roast level
 Coffee beans origin
 Extraction time, (how long are coffee beans in contact with water)
Over-extraction and Under-extraction
As a reference system, coffee specialists have created a system that evaluates a
coffee cup by the amount of desirable and undesirable compounds extracted.
This system qualifies a cup of coffee as perfectly extracted, under-extracted,
or over-extracted.
Soluble Solids Extraction Order
Water always extracts flavor compounds in this order regardless of the method:
fats and acids, then sugars, and finally the plant fibers. You can tell if coffee is
over-extracted or under-extracted mainly by taste.
The first compounds extracted from coffee are acids and fats. Acids, which give
coffee a sour taste, are the simplest compounds. This means that water is easy
to dissolve them into the coffee. Many of the light aromatics, for instance the
floral and the fruity flavors are extracted at this moment. Acids and light
flavors are very important in our final cup, it’s what give coffee its flavor.
Almost at the same time, we extract the coffee fats. The oils in coffee add body
to your cup. Fats are are hydrophobic and they wash out of the ground coffee
pretty easily. They are an important component in an espresso, unlike filter
coffee. Without fats, some of the heavier aromatics will lack. Without coffee oils
there would be no crema.
Sugars are extracted next. Water needs more time and energy to fully dissolve
them. In an espresso, these sugars are what give sweetness to your cup. This is
what creates the classic espresso flavor.
Finally the plant fibers that hold the ground coffee together will start to break
down. These fibers taste dry and bitter, and we want to avoid them. A little bit

of them give our cup some bite, but too much of these and our coffee will be
ruined.
Extractions Yield vs. Total Dissolved Solids (TDS)
Extraction yield refers to the soluble solids drawn from the coffee beans,
whereas TDS refers to the concentration of these coffee solubles in the final
brewed coffee.
We can see the extraction yield as dissolution efficiency, and TDS as the
quantity of solvent.
A ristretto has a lower extraction yield, but a higher TDS than a lungo. So
lungo brewing recipe is more efficient at extracting the good stuff from the
beans than ristretto recipe. However, lungo will also extract more bitter
compounds than ristretto.
Over Extraction
One or more of these following could cause over-extraction:
 brew time is too long,
 grind size is too fine,
 brew temperature is too high.
However, some of these factors will affect over-extraction more than the others.
From an efficiency perspective, if we would grind the coffee into a fine powder
and add hot water it will dissolve all of its delicious flavors. Unfortunately, this
wouldn’t work. It would give us a bitter cup of coffee, but interestingly, not for
the reasons you would expect…
As we just showed earlier, not all of the coffee’s flavors are good, so we have to
control the extraction and stop it just before the bitter compounds start to
break down. We do not want all of the 28% of soluble matter to go into our cup.
Fortunately, chemistry works with us on this, because most of the bitter
compounds are harder to extract, so if we stop extraction in time, we only get
the good stuff in the cup, and the bad tasting stuff stays in the grounds.
Because the bitter compounds get extracted later in the brewing process, we
need to stop pulling the shot within 25 seconds so we do not over-extract it.

Under Extraction
Coffee is under-extracted if:
 the grind is too coarse,
 brew time is too short,
 the brew temperature is too low,
 or a combination of the above.
If you don’t extract enough soluble solids from the ground coffee, the result is a
cup that is under-extracted. The flavors that bring balance to your shot are left
in the coffee grounds. Acids from coffee beans are the compounds that extract
the first, so an under-extracted shot will taste sour, maybe salty and without
sweetness.
Espresso has the shortest extraction time of all brewing methods. Because of
that it favors the extraction of the most soluble compounds, avoiding extraction
of the bitter ones. This why the espresso recipe calls for a 20 to 25 seconds
extraction time.
The short brewing time is compensated by the pressure, which introduces
entropy during extraction. Entropy, (molecule agitation), speeds up dissolution,
hence the short brew time.
However, the 20 seconds extraction time needs to be doubled by an adequate
brew temperature. The best way to calibrate for a 20 seconds extraction is by
adjusting the grind size – dialing in the espresso.
If the shot pours faster than 20 seconds it will be under-extracted. At this point
you will need to grind finer. If the shot pours slower than 25 seconds it will
likely be over-extracted, hence you will need to grind coarser.
We define a shot as 1 fluid ounce of espresso for each 7-9 grams of ground
coffee. For a doppio the shot is 2 fluid ounces for each dose of 14-19 grams of
coffee grounds. The extraction time remains the same for the different doses –
20 to 25 seconds.
Extraction and Coffee Strength
A shot of espresso is defined by the quality of the extraction, the strength of the
shot is equally important. I don’t mean caffeine content, but rather the amount
of dissolved solids in the drink.

Coffee strength depends on the ratio of ground coffee to brew water. Too little
water will make your coffee taste muddy. Too much water will make your coffee
feel thin and watery.
Strength is in a direct relationship to extraction. If you want a very strong
coffee, you can use less water to increase the strength of the cup. It’s not the
best idea, though it is possible.
One of the drawbacks of the espresso as a coffee beverage, is that the strength
of your coffee will mute more delicate flavors. The stronger a drink is, the more
difficult it will be to distinguish individual flavors. Delicate floral and fruity
flavors are often overwhelmed by sugars and oils in espresso.
Coffee Strength/Concentration vs Over-Extraction
Some home baristas confuse coffee strength with over-extraction. If a coffee is
too strong, just add a bit of water and that should correct it on the spot. On the
other hand, an over-extracted cup will taste bitter even if it is diluted with
water.
Over extraction is a bit contextual, and even subjective. This is why I am
always cautious when I use the word. What we perceive as properly extracted
in an espresso, qualifies as over extracted in drip coffee.
Some people love their coffee stronger than others. But when we brew a
stronger cup, we just do that – brew a stronger cup. We don’t over extract that
cup, we just extract a bit more stuff from the grounds.
Did we extract too much tannins from the grounds? Then yes we did over
extracted it.
Fortunately, espresso is simpler to judge than drip coffee or French press. But
when preparing a lungo or a ristretto, we need to make sure we time the shot
within the 20 – 25 seconds in order to avoid over, or under extraction. This is
why the lungo you get in a coffee shop is either short, or over-extracted. They
cannot adjust grind size. The grinder is calibrated for a a normale, or for a
ristretto, depending on the shop.
Grind Size and Extraction
Grind size is perhaps the most commonly discussed factor when it comes to
coffee extraction. When brewing espresso, the size of the grind and the amount
of coffee, or the dose, in the portafilter are the two components which are
adjusted on a regular basis in order to achieve a balanced extraction. Adjusting
grind in espresso is also known as “dialing in” espresso.

In order to nail that perfect shot that retains some sweetness, and is not overly
bitter, you need to get the perfect grind size. A good burr coffee grinder to
deliver consistent grind size, and some tweaking, are the key to a perfect
espresso.
Contrary to a popular belief, a finer grind size doesn’t necessarily produce a
better shot. Using the wrong grind size is probably the most common problem
among inexperienced baristas.
Grind size affects the extraction in two ways. Firstly, it adjusts the surface
area, with finer grinds having more contact with the water. Secondly, it adjusts
the pressure in the coffee puck, with finer grounds creating more pressure in
the coffee bed during extraction. There is also the amount of fines, which is
higher for finer grounds.
How Grind Size Affects the Pressure
An espresso machine relies on a pressure pump to force water through a
“puck” of ground coffee. As we saw earlier, the pressure introduces entropy and
this speeds up dissolution.
The espresso machine can push the water with a pressure of up to 9 bars. But
if your coffee puck is ground too coarse, water will pass through very fast, and
the pressure inside the puck won’t be nowhere near that. If the coffee is too
finely ground, the machine won’t be able to push the water through.
If you ever ground your coffee too fine, you know that water just doesn’t pass
through the coffee grinds.
A good analogy is the comparison between sand and rocks. You have the same
quantity by weight. If you pour some water on the rocks, water will
instantaneously go through. If you pour the same quantity over the sand, it will
take a bit of time to pass through the layer of sand.
How Grind Size Affects Surface Area
Imagine that you have one coffee particle and you cut it in half. The total
amount of coffee remains the same, but the water has access to a lot more
surface area inside that particle. As more coffee particles are divided into
smaller pieces, more surface area will be exposed. A smaller coffee particle can
saturate faster with water, speeding up the extraction time. In conclusion,
regardless of the brewing method, finer coffee grounds will extract faster than
coarser grounds.

A very popular recipe for espresso is extra-fine grind settings around 20 grams
to brew a single shot of espresso. The reason is to increase the coffee’s surface
area to water. In turn, this should increase extraction yield. Extraction yield
measures the amount of soluble solids that dissolve and ends up in the final
beverage. This is called a ristretto.
While this industry practice may sound good in theory, it might not be the best
approach for the flavor. When coffee is ground too fine, the flow is sometimes
too restricted and the shot is over-extracted. When the coffee puck is so tightly
packed, we risk channeling, and this is even worse than a little over-extraction.
Grind Size and Tamping
The other part of the problem is the tamping. When you tamp very finely
ground coffee, you can pack it better, so the coffee puck is more compact. This
restricts the flow even further, if you tamp too hard.
Grind Size and Fines
Finally, the fines are another variable. Any grinder produces some fines, and
this is a good thing. The fines are clogging the puck, and create flow restriction.
We want flow restriction so that water is in contact with the grounds for at
least 20 seconds. But too much fines could clog the puck too much, and the
shot will just not flow at all. Clogging is random and hard to predict.
Finer Grind Makes Stronger Coffee
Espresso brewing calls for a finer grind compared to other brewing methods
such as filter coffee or French press. Espresso coffee is stronger than other
methods. Part of the reason is the finer grind size, but let’s not forget that
espresso is brewed as a small beverage. We cannot compare a 6 fl oz, drink
with a 2 fl oz drink.
Coffee is ground finer in order to increase the surface area of the bean that is
in contact with water during extraction. This increased contact causes greater
extraction. Therefore, if coffee is ground finer and all other brewing parameters
are not adjusted, finer ground coffee will extract more coffee properties to be
dissolved into the water, resulting in a beverage with a greater TDS which is
therefore stronger. However, if more water is added to the recipe, a coffee that
is brewed using finely ground beans would have a lower level of TDS and would
be a weaker tasting product.

What Is the Perfect Grind Size?
Using a slightly coarser grind and reducing the amount of ground coffee per
shot leaves some extra room in the coffee bed, called headspace by baristas. In
turn, this technique produces a fuller, more even brewing process.
The extraction improvement will make up for the missing 3-4 grams. The
extraction yield is practically the same, and even the caffeine content is the
same. The only thing that changes is the flavor profile.
You will have to be careful though, as this change could potentially lead to an
under-extracted coffee. The shot will pour too fast and coffee will be weak and
sour. If that’s the case, just grind a bit finer.
Espresso Extraction and Coffee Brewing Temperature
Brewing temperature is one of the most important factors in coffee extraction.
Incorrect temperature, more than any other variables can lead to over-
extraction. Other brewing variables are also important for avoiding over-
extraction. However, they are amplified at higher brew temperatures. For
instance it much easier to over-extract at 205°F than at 195°F, yet both
temperatures are within acceptable parameters.
And the example I love the most: Turkish coffee uses the finest grind size
possible, the grounds are virtually powder. But because the brew temperature
is not very high, there is almost no over-extraction.
But let’s dig a little deeper into temperature, and see how is affecting espresso
extraction.
Although brew temperature can be accurately controlled on more advanced
espresso machines, it’s worth understanding how a little brew temp
modification might change your flavor profile:
 When you lower the brew temperature you will enhance acidity.
 Raising the brew temperature will decrease your cup’s acidity.
 Lowering the brew temperature can decrease extraction yield. As a direct
application, changing the brew temperature instead of the grind size is a
better way to control extraction yield.
 You can compensate with a higher brew extraction temperature for
lighter roasts.
 You can use lower temperatures to compensate for high solubility of a
dark roast.

 A larger dose will benefit from a temperature increase. A 20g dose of dry
coffee needs a higher brew temperature than 14g dose.
 Although we don’t recommend changing the the extraction time, you can
compensate for a longer extraction time by lowering the brewing
temperature.
What Is the Ideal Espresso Brewing Temperature
The ideal brew temperature for espresso is a range between 190°F and 205°F.
And if you saw elsewhere a range between 195°F and 205°F, that is not wrong,
but playing it safe.
The rate of extraction increases with higher temperature. Why not increase the
brew temperature then? Because undesirable bitter compounds are extracted
at higher temperatures. We do love some of that bite into our cup, but not too
much. The bitter flavors cannot be extracted if we lower the temperature
enough, (cold brew). But that is the other extreme.
Brewing methods with a high rate of extraction like espresso, can, and should
use a slightly lower brewing temperature. In espresso, the pressure
compensates for the slightly lower temperature and the short extraction time.
The espresso machine is built to maintain the correct temperature. Some
machines are equipped with a PID, which increases the precision of the
thermostat. Machines without a PID, require the barista to temperature
surfing, in order to ensure the correct brewing temperature.
Remember, a little kick in your brew is not bad. It’s only when you extract too
much of the bitter compounds, that we have a problem. That becomes an over-
extracted coffee.
Brew Time
Brew time, (or contact time), is the last main element that is responsible for
coffee extraction. Brew time is the amount of time that ground coffee is in
contact with the water. If other factors are adjusted so that the brewing time is
correct, it is likely that the coffee will be extracted well.
Ideal brewing time for espresso is between 20-30 seconds. This quick brewing
time is achieved by pressure that is added during brewing.
I personally aim for 22 to 25 seconds, but I can accept a 27 seconds shot of the
flow is slightly restricted.

Roast Level and Extraction
Roast level is an important factor to be considered when pulling shots. Dark
roasted beans are more soluble, so they will extract faster. Lightly roasted
coffee, on the other hand, extract slower.
In order to compensate for a light roast, the home barista need to grind finer
and reduce the dose, or increase the brew temperature.
How Pressure Improves Espresso Extraction?
The pressure is used to push the water through the coffee grounds with a high
force. This increases the agitation in the brew and speeds up the dissolution of
the soluble solids in coffee.
Along with the soluble solids dissolution, we also emulsify the oils in the coffee,
and mix in gases from the beans. The result is the crema on top of every
successfully pulled espresso shot, and a coffee with a distinct flavor, like no
other coffee extraction method.
Pump driven espresso machines push 9 bar pressure, standard pressure at sea
level. Pump driven espresso machines are high pressure coffee makers. High
pressure is also the reason that well brewed, fresh espresso has a layer of foam
or “crema” on top of the coffee.
A a properly brewed espresso is extracted between 20 and 30 seconds. Shots
pulled over 30 seconds are over extracted. The reason is again, we expose
grounds to a high temperature for an extended time.
Steam based espresso machines typically generate roughly 3 bars of pressure.
From a definition point of view, they are still espresso machines. However, the
extraction is different. The low pressure does not emulsify enough oils into the
shot, hence we don’t have crema.
To a lesser extent, other brewing methods also make use of pressure such as
the Aeropress and the percolator or the Moka pot. These methods generate up
to 1.5 bars of pressure.

Self- Check 1.1-4
Espresso Extraction
1. It is the process of dissolving ground coffee in water
a. Extraction
b. Coffee Extraction
c. Brewing
d. Espresso Brewing

2. It is where the espresso extraction is more complex than other
brewing methods.
a. Extraction
c. Brewing
d. Espresso Brewing
3. It is the process that pulls flavors from coffee grounds into the water.
a. Extraction
c. Brewing
d. Espresso Brewing
4. It is affected by many factors, including brew time, water temperature,
grind size, roast level.
a. Extraction
c. Brewing
d. Espresso Brewing
5. It is a process that is optimized to dissolve in water the maximum
amount of desirable compounds, while minimizing the amount of
undesirable elements.
a. Espresso Extraction
c. Brewing
d. Espresso Brewing
Answer Key 1.1-4
Espresso Extraction
1. B
2. D
3. A
4. A
5. A

Parts of an Espresso
1. Know the basic coffee types
2. Know more about espresso
3. Know the parts of an espresso
4. Learn the elements of tasting coffee
5. Know the types of espresso
Introduction:

Crema is the Body and Heart Make Up Shot of
Espresso
You have purchased fresh-roasted coffee, stored it
properly, and ground it just before brewing. You made
sure to grind it properly for your particular espresso
machine, tamped it properly into the portafilter
basket, and used all of the proper espresso technical
specifications. during brewing including brewing
temperature and extraction time.
Now the freshly brewed espresso shot sits in the glass and can be
observed. The premium gourmet espresso shot should reveal three
distinct layers.
Basic Coffee Types
1. Espresso
• Is coffee brewed by forcing a small amount of nearly boiling
water under pressure through finely ground coffee beans.
• Espresso - " Made on the spur of the moment"
2. Mocha
 One part espresso with one part chocolate syrup and two or
three parts of frothed milk. optionally topped with whipped
cream and chocolate drizzle.

3. Latte
 Consistency is milkier than cappuccino. One part espresso
with at least five parts steamed (hot) milk and only a small
amount of froth to top.
 Latte is less coffee and more milk and has performing latte art
by the skills Barista.
4. Cappucino
 One Part espresso with about three parts of frothed milk.
 Cappuccino is more coffee and less milk using foam milk.
 The foam milk on top of the cappuccino acts an insulator to
help retain the heat of the liquid.
More about Espresso
What makes a good Coffee?
• Water
• Espresso Machine
• Dose/ Grind
• Quality of Coffee beans
• Barista
3 Parts of an Espresso

1. Emulsion - The "CREMA" is produced when
the oil get emulsified by the pressure of the espresso
machine. The crema helps to hold in the flavors and
aromas of the coffee. Emulsion contains sugar, oil
and protein.
2. Suspension - These are the tiny particles and
gas bubbles that are suspended in an espresso. It
help inhibit the bitter flavor of the coffee and they
contribute to the fullness and body of espresso.
3. Solution - This is the water soluble elements
of a coffee, it is the same elements you get in a cup of a brewed
coffee. It is also the solid and the heart of the espresso.
Good Shot Coffee
1) Volume
2) Amount of coffee ground
3) Extraction Time
4) Tamping Pressure
5) Ideal grind for machine
6) ATM Pressure
7) Water Temperature
8) Crema
9) Pouring rate
How to tell over extraction?
• Bitterness or a strong harsh flavor
• Dark thin crema
• Dark Halo at the edge of the cup
Elements of tasting Coffee
1) Flavour - The way in which the tongue interprets the aromatic
characteristics of the coffee. It conveys a specific taste or flavor such as
chocolate, nutty, spicy or smoky

2) Acidity or brightness - The zing of life in a cup of coffee. It can be
described as a pleasant tangy or harp feeling on the sides of your tongue
and on the back of your palate.
3) Body - The sense of heaviness or thickness of coffee in your mouth. A
full-bodied coffee will feel as if it has more volume and texture, while a
light- bodied coffee seem to be very watery or thin.
4) Aroma - The immediate appeal to the olfactory (smelling) senses.
Aroma often sets up a level of taste expectation just before the coffee
touches your tongue.
5) Finish - The Finish of a coffee is literally the aftertaste. A finish can
be described as clean (quick) on one of the scale or as lingering (long) on
the other.
Types of Espresso
1. RISTRETTO - Italian for Shortened
- Extracted using less water
- Strong taste
- Also referred to as "SHORT BLACK
2. LUNGO - Italian for Long
- made by running about double amount
of water through ground coffee
- Also referred to as "LONG SHOT"
3. DOPPIO - Italian for double
- Two measure of coffee beans
- Also referred to as "DOUBLE SHOT
4. AMERICANO - Espresso with additional
hot water added to the extracted coffee

5. CORETO - Italian for Corrected
- Where in liquor is added to the extracted
espresso coffee.
OTHER COFFEE VARIATIONS
• Espresso con panna - espresso with a dollop of whipped
cream
• Espresso machiato - espresso with a dollop of milk foam
• Flavored Latte -
• Flavored Cappuccino -
• Mocha- Flavored -

Self- Check 1.1-5
Multiple Choice: Choose the correct answer or letter.
1. It is coffee brewed by forcing a small amount of nearly boiling water
under pressure through finely ground coffee beans.
a. Espresso
b. Mocha
c. Latte
d. Cappucino

2. It is one part espresso with one part chocolate syrup and two
or three parts of frothed milk. optionally topped with whipped
cream and chocolate drizzle.
a. Espresso
b. Mocha
c. Latte
d. Cappucino
3. It is one part espresso with at least five parts steamed (hot)
milk and only a small amount of froth to top.
a. Espresso
b. Mocha
c. Latte
d. Cappucino
4. It is one part espresso with about three parts of frothed milk.
a. Espresso
b. Mocha
c. Latte
d. Cappucino
5. These are the tiny particles and gas bubbles that are suspended in an
espresso.
a. Emulsion
b. Suspension
c. Solution
d. Crema
Answer Key 1.1-5
1. A
2. B
3. C
4. D
5. B

Espresso Machine Parts
1. Know the tools and equipment used in coffee shops
2. Know the meaning of an Espresso Machine
3. Learn the parts of an Espresso Machine
4. Learn the factors that affect extraction time
Introduction:

We all know that coffee shop lingo is its own kind of code – a latte
means less foam in some places and more milk in others – and it takes
several trips to any given shop to master its unique language. As an
employee of a café or restaurant that utilizes an espresso machine, or
even just a home barista, there are certain standardized components
that you should be familiar with. Here are the parts every barista should
know:
Tools and Equipment Used in Coffee Shops
1. Grinder
Two Types of Grinder
1. Manual coffee mill or Hand mill- A box type mill
that holds a small amount of coffee beans which has
been used for hundreds of years. It is used by
placing beans inside the lid and by rotating the
handle. Coffee grounds, which are fairly consistent in
size, then into the drawer.
2. Blade Grinder- Has a blade in the center of the
grinder
3. Burr Grinder- Is made up of two revolving abrasive
surfaces (called burrs). It is considered as the best
all around domestic grinder. Burr mills are noisy
and slow but produce precisely uniform grind of
coffee.
4. Espresso Grinder- a doser or espresso grinder is
the usual companion of a professional espresso
machine. This grinds the beans between metal
discs that have gear shaped edges like the burr
grinder. However, there is only one grind setting,
and the grind is selected by calibrating the grinder
adjustment collar to produce a perfect shot of
espresso.
5. Institutional Grinder- commercial grinder that can
produce any type of desired grind in a small

amount of time. Knob is also used to select the type of grind
Parts of a Grinder
Meaning of an Espresso Machine
An espresso machine is a coffee brewing device that focuses on
espresso, using steam and pressure to craft highly concentrated shots.
It’s a relatively new invention, crafted back in the late 1800’s as a faster
way of making the drink. Before then, traditional brewing usually
involved grinding and steeping in hot water. Nowadays, the espresso
machine is a readily available form of equipment for both commercial
and home spaces.

What’s The Difference Between An Espresso Machine And a Coffee Maker?
While superficially similar, espresso machines and coffee makers couldn’t be
more different. An espresso machine is designed to craft espresso, a highly
concentrated form of coffee with a layer of golden crema. This is achieved using
a portafilter, steam, and pressure.
A coffee maker creates drip coffee by soaking ground beans through a paper or
cloth filter. Drip coffee is thinner and darker, similar to what you achieve with
a pour over.
Espresso Machine
Is a recent innovation in the way to prepare coffee obtained its origin in 1822 of
the first crude espresso machine in France.
The Italians perfected this machine and were first to manufacture it. Bezzera
were the first to manufacture espresso machine
Extraction Time: 20-30 seconds
Parts of an Espresso Machine

1. Head
The group head is the main part of the espresso machine and it is responsible
for espresso. It is called a brew group or brew head.
It is at the front side of the espresso machine that puts the water from the
espresso machine into the filter basket. We can insert our portafilter in the
group head while preparing espresso.
2. Portafilter
The portafilter is one of the important parts of an espresso machine. The
portafilter is a Portable Filter or filter holder. It looks like a metal basket, and
grounded coffee puts into a portafilter bucket.
This portafilter is placed in the group head and locked within-group the head.
After applying the pressure, liquid espresso comes out from two spouts.
3. Portafilter Spring
The portafilter springs hold the baskets in place. This portafilter spring is
placed into the groove that is drawn into the inner side of the portafilter body.
Most portafilter springs are hexagonal, and one end is open. Also, some of the
portafilter springs are circular.
4. Basket of Portafilter
The portafilter basket is nothing but a filter screen, and it locates within the
portafilter. This portafilter basked may be the single or double size and placed
in portafilter using spring.
5. Group gasket
The group gasket is nothing but a ring of rubber. The function of the group
basket is to seal the portafilter and portafilter basket to the group.
It is placed and inserted into a groove that is drawn into the group. Whenever
portafilter leaks, it’s compulsory to change the group basket to avoid the
leakage,

6. Group Screen
The group screen is found in the group head from which hot water flows. It is
also called a dispersion screen pr shower screen.
7. Drip Tray
It is a tray on which we can place a coffee cup. It is removable. There is a
provision for adjusting the height of the cup in it.
8. Group Dispense Switch
The group dispense switch works similar to the dosing keypads, but it is a
simple On/OFF switch. It is on top of the groups. Some automatic espresso
machines have a dispense button, which gives additional functions for
operation.
9. Group Dosing Keypad
Group Dosing keypads are used in both automatic and super-automatic
espresso machines. There are buttons on the group dosing keypad. When we
press that button, the group head machine activates.
10. Hot Water Trap
A hot water tarp is also called Americano Wand.
11. Power Switch
The power switch is on the backsplash of the espresso machine. This power
switch shows the reading from 1-0-2. The general position for full operation is
the 2 position, and it may vary depending upon our requirement.
12. Pressure Gauge
The pressure gauge is on the front side of the machine. It has two needles or
hands which show both boiler pressure and pump operating pressure.
This pressure gauge helps to monitor the health of the espresso machine also
other parameters like the pressure and temperature of the espresso machine.
13. Sight Glass
All espresso machines have sight glass and it’s found on the front side of the
espresso machine. Its main function is to show the water range in the boiler.
Sight glass is nothing but a water level gauge. There are 2 marks Minimum and
Maximum.

14. Steam Wand
A steam wand is a tool that produces foams in steaming milk while making
espresso. This steam wand looks like a solid metal pipe and can activate by
using a valve or lever depending upon the type of espresso machine.
The steam wand connects to the boiler to flow the steam. It was created by the
boiler and used to froth the milk.
15. Steam Tip ( Steam Wand tip)
The steam tip is also named a steam wand tip. This steam wand tip is
connected to the end of the steam wand.
The main function of the steam wand tip is to disperse the steam that is
coming from the steam wand in the splayed pattern.
16. Adjustment Ring or Knob
The adjustment ring or knob is found ON side of the bean hopper. It helps to
grind the coffee beans in a coarse, or fine mixture depending upon the
requirement. When we rotate the knob, it starts grinding coffee beans into the
fine powder
17. Bean Hopper
A Bean hooper is a large and clear container on top of the grinder. Generally, it
is of plastic or glass type. The Hopper holds your espresso bean and feeds the
beans into your grinder. It burrs the coffee bean when we rotate the knob.
18. Doser
The doser is a chamber in front of the grinder. The doser is to hold the ground
coffee in the container which goes into the portafilter.
19. Single/Double Doser Button
These are the buttons that give us the option of dose of coffee. According to the
requirement, we can select the dosing option.
Factors that affect extraction time
1. Dose - how much coffee you put in the portafilter (7-9g/ 14-18g)
2. Tamp - how hard you pack the coffee in the portafilter (30-50 lbs.)

3. Grind - how fine or coarse the coffee is ground. (fine/ espresso grind)
Self- Check 1.1-6
Multiple Choice: Choose the right answer or letter,
1. It is one of the important parts of an espresso machine.
a. Head
b. Portalifter
c. Group Gasket
d. Group Screen
2. It is the main part of the espresso machine and it is responsible for
espresso.
a. Head

b. Portalifter
c. Group Gasket
d. Group Screen
3. It is to seal the portafilter and portafilter basket to the group.
a. Head
b. Portalifter
c. Group Gasket
d. Group Screen
4. It is found in the group head from which hot water flows.
a. Head
b. Portalifter
c. Group Gasket
d. Group Screen
5. It is also called Americano Wand.
a. Head
b. Hot Water Trap
c. Group Gasket
d. Group Screen
Answer Key 1.1-6
1. B
2. A
3. C
4. D
5. B

Performance Criteria Checklist 1.1-6
TASK SHEET 1.1-6
Title: Espresso Machine Parts
Performance Objective: Given the necessary tools, materials and
equipment, you should be able to prepare requisitions for maintenance
services following industry accepted standards within 2 hours.
Supplies/Materials :Paper or notebook, ballpen and pencil
Equipment: Espresso Machine
Steps/Procedure:
1. Wear your PPE.
2. Observe safety and proper sanitation
3. Prepare the needed tools, equipment and materials.
4. Follow the steps/procedures below:
 Draw or layout the espresso machine
 Label each parts
5. Clean the area and return all the tools/materials in their proper
places.
Assessment Methods:
 Demonstration

CRITERIA
Did you…. YES NO
Wear your PPE?
Observe safety and proper sanitation?
Prepare the needed tools, equipment and materials?
Prepare draw or layout the espresso machine parts?
Label each one properly?
Clean the area and return all the tools/materials in their
proper places?
Finish the task on allotted time?
References:
https://coffeeandteacorner.com/coffee-roast-levels-explained/

https://brewespressocoffee.com/espresso-extraction/
https://coffeeofthenorth.org/what-are-the-4-types-of-coffee-beans/
https://gourmetcoffeelovers.com/types-of-coffee-grinds/
https://espressocoffeeguide.com/3-parts-espresso-shot/
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Espresso Barista's Guide to Preparing and Steaming Milk

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Espresso Barista's Guide to Preparing and Steaming Milk