Module 1: Chapters 1&2 Wine Comp, Chem, Faults,

Question 1

A highly volatile acid, often found in vinegar.*

Answer 1

Acetic Acid

Question 2

The main type of potable alcohol found in wine.*

Answer 2

Ethanol or Ethyl Alcohol

Question 3

The main acid found in grapes and wine.*

Answer 3

Tartaric Acid (also strongest in pH)

Question 4

The two fermentable sugars found in grapes and wine.*

Answer 4

Glucose and Fructose

Question 5

Molecules that are formed by the joining of an acid and an alcohol.*

Answer 5

Esters

Question 6

This wine fault is often decribed as smelling like ‘burnt matches.’*

Answer 6

Sulfur Dioxide

Question 7

This type of molecule often results when wine is exposed to air.*

Answer 7

Aldehyde

Question 8

This wine fault often smells like nail polish remover.*

Answer 8

Ethyl Acetate

Question 9

This substance often makes a wine smell of onions or garlic.*

Answer 9

Mercaptan

Question 10

This compound is responsible for the red, blue, or purple hue found in red wines.*

Answer 10

Anthocyanin

Question 11

This acid is like to crystallize and form “wine diamonds.”*

Answer 11

Tartaric Acid

Question 12

The common name of the wine fault caused by TCA (2, 4, 6-trichloranisole).*

Answer 12

Cork Taint (or ‘corked’)

Question 13

The chemical the gives Sherries their unique “oxidized” aroma.*

Answer 13

Acetaldehyde

Question 14

The most likely cause of the ‘geranium’ fault.*

Answer 14

Incomplete malolactic fermentation

Question 15

The most likely cause of a wine that has an unpleasant aroma of Band-Aids, as well as a ‘sweaty’ or ‘horsey’ aroma.*

Answer 15

Brettanomyces (Brett)

Question 16

The five major components of wine.

Answer 16

Water (80-90%)
Alcohol (10-15%)
Acid (.5-.75%)
Sugar (15-28% contained in grapes at harvest, converted largely to alcohol, remaining portion is called residual sugar. Comprised of two sugars, glucose and fructose.)
Phenolic Compounds (trace amounts, but have large sensory effect)

Question 17

Is water added to wine?

Answer 17

Uncommon winemaking practice, occurring only when potential alcohol, actual alcohol, or phenolics are beyond desired levels.

Question 18

True or false: Ethanol is a volatile compound.

Answer 18

True. Evaporates easily, carrying aromas to the nose.

Question 19

What is “weight” or “body”?

Answer 19

The tactile sensation of wine on the palate. ALCOHOL CONTENT is one of the determining factors in weight (higher=heavier). Higher alcohol can also contribute slower, thicker tears or legs in the glass after swirling.

Question 20

What does acid do in wine?

Answer 20

Gives structure, balance, and thirst quenching refreshment (especially in white wines).

Question 21

Do ‘wine diamonds’ dissolve back into wine?

Answer 21

No. Once in that form they have fallen out of the wine. They can be avoided or minimized by the process of cold stabilization.

Question 22

What is Malic Acid, where is it found, and how is it combated?

Answer 22

A sharp-tasting acid associated with GREEN APPLES. Found in under-ripe or cool-climate grapes. Combated by the process of MALOLACTIC FERMENTATION.

Question 23

Is Citric Acid a normal component of grapes?

Answer 23

No. It is occasionally added to increase total acidity, but tropical flavors make unsuitable for high quality wines.

Question 24

Is Lactic Acid found in grapes? If not, where does it come from and what does it do?

Answer 24

No. Created by lactic acid bacteria during MALOLACTIC FERMENTATION. It is less intensely acidic than Malic Acid, making softer and smoother wines and providing them with a creamy texture and sometimes a “buttery” aroma. It is also created in very small amounts during primary fermentation.

Question 25

What causes higher concentrations of the ‘vinegar smell’ of acetic acid? Is acetic acid present in grapes?

Answer 25

A chemical reaction between ethanol and and oxygen caused by ACETOBACTER, a harmful (to wine) bacteria.
It is not present in grapes, but is created during fermentation.

Question 26

Is Succinic Acid present in grapes? What effect does it have?

Answer 26

No. It is created as byproduct of normal alcoholic fermentation, and has a sharp, slightly bitter, slightly salty flavor.

Question 27

What is TA?

Answer 27

Total Acidity. A measurement of the volume of all acids in a wine. Along with pH, gives a full picture of a wine’s acidity.

Question 28

What is pH, and what does it help determine?

Answer 28

pH is the measurement of the combined chemical STRENGTH of the acids present in the wine (lower pH = stronger acid content).
pH indicates stability and helps determine sulfur additions.

Question 29

True or false: Grapes contain roughly equal amounts of fructose and glucose.

Answer 29

True. Both are highly fermentable simple sugars (monosaccharides).

Question 30

True or false: Given the right conditions, yeast that is able and allowed will ferment a wine to dryness.

Answer 30

True. However, even dry wines contain trace amounts of unfermentable sugars, below one’s ability to detect.

Question 31

What does residual sugar add to wine?

Answer 31

Weight and viscosity, which influences mouthfeel, body, and texture of the wine.
It is left when fermentation is stopped (either naturally or by winemaker) before all sugar is fermented to ethanol.

Question 32

True or False: The color of a red wine is influenced only by anthocyanins.

Answer 32

False. Acidity level also plays a role. More acidic wines appear redder, less acidic appear bluer.

Question 33

Where are flavonols found?

Answer 33

These are yellow pigments found in white wine. Sunnier climates produce more golden wines, while cooler or cloudier climates produce paler wines.

Question 34

Where are tannins found? What do they do?

Answer 34

Astringent, bitter compounds found in oak and oak barrels. Natural preservative protecting red wine from oxidation during aging.
When present in young wine, they are identified by the textural drying sensation in the mouth.

Question 35

Where is vanillin found?

Answer 35

Found in oak. Phenolic compound that is the same that found in vanilla beans.

Question 36

True or False: White wines are richer in phenolic compounds.

Answer 36

False. Phenolics are concentrated in skins and seeds of grapes; because of this, red wines are richer in phenolics.

Question 37

What is ‘sediment’?

Answer 37

Polymerized phenolics, particularly pigments and tannins, that fall out of solution over time.
In many cases this creates an aged wine with lighter color and less astringency.

Question 38

True or false: Aldehydes also form after a wine is exposed to heat.

Answer 38

True. Along with being open too long, this is a common cause of oxidation.

Question 39

True or false: Esters are the largest group of odiferous compounds in wine.

Answer 39

True. Many are desirable in low concentrations, but are considered flaws at higher concentrations.

Question 40

Oxidation

Answer 40

Dissolved oxygen in wine. Curtailed during winemaking by the addition of sulfur, which absorbs free oxygen molecules.

Question 41

Petillance

Answer 41

Leftover CO2 that creates a slight bubbling under the surface of the wine when the wine is poured.
The CO2 keeps the wine feeling fresh and lively and promotes release of aromatic compounds.

Question 42

What does sulfur do?

Answer 42

An important preservative to keep wines stable after fermentation. Produced in minute quantities during natural fermentation, all wines contain at least trace amounts.

Question 43

What is the US interstate commerce limit on sulfur dioxide?

Answer 43

10 parts per million. Anything higher must display the “Contains Sulfites” warning on the label.

Question 44

What are the characteristics of cork taint, and what is its technical name?

Answer 44

Musty , moldy odor, similar to a dank basement. Caused by a mold that grows in the bark of the cork tree, on winemaking implements, and even in the winery itself.
The mold interacts with other compounds to create 2,4,6-trichloranisole (TCA), the technical name for cork taint.

Question 45

True or false: Cork taint is harmful if ingested.

Answer 45

False. “Corked” wine may simply taste muted in milder cases, and is not harmful to ingest.

Question 46

How persistent/prevalent is cork taint?

Answer 46

Very persistent. If saturating any part of winery’s environment (boxes, barrels, even walls), it can even transfer to screw cap bottles.
Industry experts estimate between 1% and 8% of bottles every year show cork taint.

Question 47

True or false: Cork taint has a high recognition threshold.

Answer 47

False. TCA has a VERY LOW recognition threshold (2-7 parts per TRILLION), and is unmistakable once identified.

Question 48

True or false: The sensory effects of SO2 are directly related to Total Acid in the wine.

Answer 48

False. SO2 is directly related to pH levels. The more acidic the wine, the more pronounced the SO2 will be.

Question 49

What causes a ‘rotten egg’ smell in wine?

Answer 49

Hydrogen Sulfide (H2S). Occurs most often when a barrel or tank rests too long on a large amount of yeast sediment, and has also been reported in screw cap bottles that are impervious to oxygen. 
Sulfur rich wine + sitting too long in absence of oxygen = Hydrogen Sulfide

Question 50

Mercaptan is caused by what?

Answer 50

A combination of sulfur and ethanol. It is the odor added to natural gas in order to detect leaks.
It is a SERIOUS defect, and less remediable than the other two sulfur compounds (SO2 and H2S)

Question 51

Most bacteria cannot survive the highly acidic environment in wine. What are the major exceptions, and what do they do?

Answer 51

Lactic bacteria: Responsible for malolactic fermentation, intentional or otherwise. May create Lactic Acid, described as smelling like sauerkraut or a goat.
Acetobacter: Converts alcohol into acetic acid, giving a smell of vinegar. The term “Volatile Acidity” (VA) is applied to wines with decided aromas of white vinegar.

Question 52

What is ‘ascensence’?

Answer 52

Term referring to a fault in wine with discernible VA accompanied by a high level of ethyl acetate (nail polish remover smell).

Question 53

What does butyric acid create?

Answer 53

The odor of rancid butter or spoiled cheese.

Butteric Acid

Question 54

What creates a ‘green’ odor?

Answer 54

Odor of leaves is created by the use of under-ripe grapes.

Question 55

What does oxidation cause in non-sherry wines?

Answer 55

A lack of fruit character and occasionally browning of the wine itself.

Question 56

What is ‘Maderized’?

Answer 56

A cooked or baked odor as a result of excessive heating or oxidization. Generally a fault, but considered acceptable in wines like Madeira that are deliberately heated.

Question 57

What causes a rubbery odor?

Answer 57

Extremely low-acid wines or excess sulfur.

Question 58

What does the term ‘reductive’ describe?

Answer 58

Odors resulting from conditions lacking oxygen i.e. rotten eggs, garlic, struck matches, cabbage, or burnt rubber.