From the wine and grape program

1. SensoryTraining
“Know thyself before making a judgment”

2. Sensory Evaluation/Science
• A scientific discipline used to
• evoke,
• measure,
• analyze and
• interpret
reactions to characteristics of food and materials
as they are perceived by senses of sight, touch,
hearing, smell and taste.
• Here, the human being serves as a measuring
instrument, comparable to other laboratory apparatus.

3. What it isn’t
Influence of wine glass size on the sensory properties of white wine

4. Know your instrument
• Here, the human being serves as a measuring instrument,
comparable to other laboratory apparatus.
• Wine judges??
• evoke,
• measure,
• analyze and
• interpret
• Know and understand yourself, your capacities, limitations
and biases!

5. Humans are
different
• We perceive things differently!!

9. We perceive things differently

13. DETOUR
SENSITIVITY TEST

17. Our senses influence
each other
• Sensory interaction is the process by which our five
senses work with and influence each other.
• Sensory interaction helps us complete many tasks,
including tasting our food and understanding a
conversation.
• Smell and taste are two senses that commonly interact
with each other
• Sight and taste often interact with each other

19. Smell
• In contrast to the small number of basic tastes, humans
are able to recognize more than 10,000 different odors.
• Unlike taste, humans are amazingly sensitive to smell.
• We are able to detect the aroma of certain volatile
compounds at the level of one part per trillion, and a
few at levels even 1000 times lower.

20. Flavor
The combined perception of taste
and aroma

21. DETOUR

22. Guess the food!!
3
volunteers
Wear
nose clips
Wear eye
covers
Taste Respond

23. Product 1
• BASIL

24. Product 2
BBQ Sauce
This Photo by Unknown Author is licensed under CC BY-SA-NC

25. Product 3
Coffee

26. Physiological biases-
Adaptation
• It results in a decreased sensitivity of your sensory organs
after repeated stimulation by the same smell or taste.
The graph shows how taking repeated sniffs/sips over a glass
of wine decreases your perception of the overall aroma
intensity of the wine.

27. Physiological biases –
Increase or Decrease Error
• Occurs when two stimuli interact with each
other providing a greater (or lesser) total
intensity than the two single stimuli.
• For example, a sugar water solution is
perceived sweeter if consumed in the
presence of the smell of vanilla (interaction
between the senses – increase error).
• Similarly, residual sugar in wine (or coffee)
reduces the bitter intensity (decrease
error).

28. Physiological biases –
Other Errors
• Pathological errors:
• occur when the subject has temporary or
permanent physiological deficits, that make
him/her unable to perceive some smells
(anosmia), some flavors (ageusia), some colors
(color blindness) or other sensory stimuli.
• Threshold error:
• due to the different threshold of perception
(sensitivity) that individuals have,
• two people with very different sensitivity can
associate a different intensity to the same
stimulus.

29. Tricks of the mind - Expectation

30. Tricks of the mind –
Halo Effect
• Caused by the overlapping of attributes and
characteristics of the sample.
• For example, if we need to evaluate the
crunchiness of an apple, the wrinkled
appearance of its peel will inevitably affect
our evaluation.
• To counter the effect:
• evaluate each aspect of the wine (i.e., smell, flavor,
mouthfeel, and appearance) independently.
• taste the same wine in different flights and with
different codes to assess different sensory
modalities.

31. Tricks of the mind - Stimulus
Error
• Occurs when judges are influenced by irrelevant
details that “suggest” differences between the
products.
• A group of sommeliers were asked to describe
a white wine sample which was artificially
colored red.
• Stimulus – the color
• Effect – they described the wines using red
wine descriptors, not actually present in the
sample

36. Taster status
• some people are extremely sensitive to the taste of bitter
substances (SUPER TASTERS) , while others perceive little or no
bitter taste (NON TASTERS).
• In the middle is everyone else .
• Using a well-known bitter tasting chemical named 6-n-
propylthiouracil, or PROP for short we can test your status
• About 25% of the population is extremely sensitive to the taste of
this chemical, an equal portion (25-30%) cannot taste it.
• That leaves about 45-50% of the population to be “average” in their
ability to taste PROP.

37. Status and preferences
• Super tasters – more sensitive to taste
(genetics + number of papillae)
• Non tasters – less sensitive
• Food choices
• Alcohol behavior
• Health implications

38. Conclusions
• Know yourself
• Be aware of biases
• Try to mitigate, where possible
• Educate others

39. BREAK TIME!

40. Wine Faults

41. Volatile acidity
• Also known as VA
• Substances responsible:
• acetic acid
• ethyl acetate
• Smells like?
• Vinegar (AA)
• Nail polish remover (EA)

42. Volatile acidity
• Common causes
• space on top of tanks/barrels
• damaged fruit
• low SO2
• poor winery hygiene
• unhealthy malolactic fermentation
• Wines most likely to be affected
• all
• more acceptable in reds at low levels

43. Volatile acidity
• Microorganism responsible
• Acetobacter sp.
• Lactic acid bacteria
• How to fix it?
• at low levels just drink the wines
• blend with low VA levels wines
• at high levels – send to vinegar factory or dump

44. Oxidation
• Substance responsible
• acetaldehyde (degradation of ethyl and acetate esters)
• Smells like?
• brown apple
• sherry
• papery flavor

45. Oxidation
• Common causes
• low SO2 during winemaking
• high dissolved oxygen
• contact with oxygen (empty space on top of tanks)
• low SO2 at bottling
• Wines most likely to be affected?
• whites
• How to fix it?
• Some success with casein or PVPP fining

46. Sulfides (H2S)
• Substances responsible
• Hydrogen sulfide
• Mercaptans
• Dimethylsulfide (DMS)
• Smells like?
• Boiled eggs
• Onion, garlic, burnt rubber
• Tinned corn, cooked vegetables

47. Sulfides
• Common causes
• Lack of aminoacids (nitrogen) in fermenting juice or must
• Excessive aminoacids in juice or must
• Ratio of amino acids (high glutamic acid, alanine, GABA)
• Reductive winemaking (lack of oxygen)
• Organism responsible
• Yeasts (Saccharomyces sp)

48. Sulfides
• Wines most likely to be affected
• all, particularly reds
• at very low conc. may add complexity to wines
• How to fix it
• Avoid it by adding yeast nutrients
• If present –
• Aeration in early stages (boiled eggs)
• Copper sulfate fining
• Lees fining

49. Brettanomyces (Brett)
• Substances responsible:
• 4 ethyl phenol, ethyl guaiacol
• 4 vinyl phenol, vinyl guaiacol
• Unknown
• Smells like?
• Band aid
• Spicy
• Horse stable
• Barnyard
• Plasticky/chemically pungent

50. Brettanomyces
• Common causes
• Low SO2 levels
• High pH, low TA
• Increased storage temperatures
• Infection during barrel storage
• Inadequate barrel/cellar hygiene
• Microorganism responsible
• Brettanomyces sp. (yeast)
• Wines most likely to be affected
• reds, particularly those stored in barrels
• Sometimes seen as an expression of terroir, particularly in Old World reds (most of all, French)

51. Mousy taint
• Substance responsible
• Acetyl tetra hydro pyridines
• Smells like?
• Mouse urine
• Corn chips
• Jasmine rice

52. Mousy taint
• Common causes
• Low SO2
• High pH
• High storage temperatures
• Microorganisms responsible
• Lactobacillus brevi (bacteria)
• Oenococus oeni (MLF)
• Sometimes Brett

53. Mousy Taint
• Wines most likely to be affected
• Reds
• Fortified reds (higher pH, barrels storage)
• This particular taint –
• Hard to smell
• Develops in mouth after spitting/swallowing
• The compounds do not become volatile (and thus
detectable) until they mix with something that increases the
pH of the solution. This is most commonly saliva, hence
mousiness normally only announces itself on the finish of a
wine.
• Sometimes accompanied by strong metallic bitterness

54. Cork Taint
• Substances responsible:
• 2,4,6 trichloroanisole (TCA)
• tribromo anisole (TBA)
• geosmin
• octenol
• methylsorborneol
• Smells like?
• Musty
• Earthy
• Mushroom
• Compost
• Wet dog
• Wet cardboard

55. Cork Taint
• What causes it
• cork contamination
• Chlorine from bleach treatments
• Binds with phenols in cork
• storage in musty barrels
• atmospheric contamination
• bromine containing insulation and fire retardants
• Microorganisms responsible
• Not clear
• Armillaria mellea
• Streptomyces
• Aspergilus sp

56. Thank you!
Hope you had fun.
Andreea.Botezatu@ag.tamu.edu