John Laird talks about how by deeping our understanding of our roasting systems and the physical process of roasting, we can be more purposeful and proactive with defining roast profiles to meet our objectives. Also he emphasizes how data collection and evaluation is essential to developing our intuition related to the roasting process. http://nordicbaristacup.com/2013/11/john-laird-roadmap-to-purposeful-profiling/

1. Exploring coffee chemistry and a
roadmap to purposeful profiling
John Laird
Nordic Roaster Forum November 8, 2013

2. Purpose




To develop a greater understanding of the
relationship between our roasting systems, our
coffees, and the chemical and physical changes that
occur during the roasting process.
To understand the relationship of roast progression
at specific periods during the roasting process and
the effects on the roasted coffees
To translate this to intentional proactive profiling and
greater control over the outcome of our roasts.
Think Differrently.

3. Profiling?





What do we mean by the term Profiling?
Profiling is a description of the inputs and results of
our process.
A plan for controlling the development path of our
roasts.
A method of ensuring consistency of our roasts.
Timing is everything

4. Our Role as a Roaster







Understanding our customers.
Understanding our product.
Develop our stylistic approach.
What are our objectives? Filter coffee / Espresso
Roast delicious tasting coffee.
There is no such thing as a perfect roast.
As soon as we decide that we’ve got it all figured out
is the time that we stop learning.

5. Coffee Terminology


Acidity. Acidity is the essential quality of coffee that that
can be either over or underwhelming, but when crafted
into a balanced roast often defines the overall character
of a coffee.
Acidity can be used to describe both the actual chemical
acidy present in the coffee or to describe the perception
of the remaining transformed acids that more clearly fit
with the term perceived acidity.

6. Coffee Terminology

Aroma. Aromas are the sensations perceived through
our sense of smell which also contribute greatly to the
perceived flavors of brewed coffees. Aromatics released
during the roasting process can range from dry grass or
hay, to caramel or buttery during the various stages of
the roast.

7. Coffee Terminology

Body. Body is a physical sensation that refers to the
perception of weigh on the palate or “mouthfeel”. Body
can be an inherent quality of a particular coffee as well
as a roast induced characteristic.

Balance. That point in a roast where the favorable
characteristics of the cup are harmonious to each other.
An aggressively acidic low body coffee, or a flat dull and
heavy bodied coffee that would be considered
unbalanced however could possibly be considered
enjoyable by some.

8. Roasting - Terminology

Air Flow: Refers to the total volume of air passing
through the roasting chamber measured as standard air
at ambient temperature. US measure is cubic feet per
minute ( ft3/min) and metric is cubic meter per hour
(m3/hour).

Bean Temperature: Refers to the temperature recorded
by a thermocouple or RTD which is immersed in a steady
stream of coffee contained in the roasting chamber.
Bean temperature measurements vary widely depending
on probe placement and are different from machine to

9. Roasting Terminology Cont’d

Charge Temperature: Is the temperature of the roasting
chamber immediately prior to releasing the green coffee
in to the roasting drum at the start of the roast.

Drop Temperature: Is the temperature recorded by the
bean probe at the termination of the roast.

Environment Temperature: Refers to the temperature of
the air exiting the roasting chamber after has transferred
its heat energy to the roasting coffee.

10. Roasting Terminology Cont’d

Rate of Rise: The rate of temperature rise of the bean
mass, usually expressed in degrees per minute.

Roast Development Time: The period of time the roast
continues from the start of first crack until the
completion of the roast.

11. Roasting Systems





Purpose of a Coffee Roasting System
Various Types of Roasting Equipment
Impact on Profile Description
Understand relationship between Environment temp
and bean temp.
Coffee temperature / heat capacity.

12. Probat -Single Pass

13. Probat Recirculating

14. Carbohydrates



Carbohydrates – (Sugars)
 Monosaccharides
 Ogliosaccharides
 Polysaccharides
Simple Sugars Necessary component of Maillard
reaction.
Melting point:160C -200C range,(320-392F)

15. Proteins






Account for roughly 10 to 13% of coffee’s dry weight
Amino acids that are a necessary component in
producing Maillard reaction.
Critical for development of :
Color
Aroma
Flavor

16. Chlorogenic Acids




Chlorogenic acids are the large family of esterified
compounds present in green and roasted coffee.
During roasting, CGA's slowly decompose to form
caffeic and quinic acid. Roughly 50% of the original
CGA will decompose in a medium roast
Make up 7% of dry weight of green coffee.
Degrade as roast progresses.
Total concentration of acids degrade from 1.6% at a
light roast to 0.71% in dark roasts.

17. Quinic Acid

Quinic acid along with citric and malic represent a
significant portion of coffee's total acid content.
During roasting quinic acid progressively increases
as the levels of chlorogenic acid decrease

Increases as roast progresses

18. Citric Acid

During roasting, citric acid reaches a maximum at
light to medium roasts then quickly diminishes as
roasting levels progress. A typical medium roast will
lose about 50% of its initial citric acid concentration
and with progressive destruction in latter stages of
roasting progresses. Boiling pt.153oC (307oF)

Increases initially then rapidly decreases as roast
progresses

19. Maillard Reaction





The primary Browning reaction of many cooked
foods.
Results from a chemical reaction between an amino
acid and a reducing sugar.
Reaction promoted by heating,
Virtually no amino acids remain after 5 minutes at
220˚C (428 ˚C)
Occurs in the presence of melted sugars 160C
-200C range,(320-392F)

20. Carmelization





An entirely different process from Maillard browning.
Results are sometimes similar Visually and taste.
Caramelization may sometimes cause browning in
the same foods in which the Maillard reaction
occurs.
They both are promoted by heating
Caramelization is basically the pyrolysis of certain
sugars.

21. Proactive Profiling









So what does all of this mean?
Consider your objectives.
Know your green - Sample roasting
Importance of the Rate of rise
Hit your targets
Roast development time
End of roast
Timing is everything
Think outside the box - Interpolation

22. Costa Rica – PR-0024

23. Costa Rica – PR-0025

24. Costa Rica – PR-0026

25. Costa Rica – PR-0027

26. Kenya – PR-0028

27. Kenya – PR-0029

28. Kenya – PR-0030

29. Kenya – PR-0031

30. Costa Rica – Roast Defect

31. Kenya – Overlay