2. Wine Faults

Question 1

What does TCA stand for?

Answer 1

2,4,6-Trichloroanisole

TCA is a chemical created when a mold that grows on and in the bark of cork trees interacts with other components in a wine. This will cause the wine to have an unpleasant odor, similar to that of a dank basement.

Wines suffering from this condition are known to be corked or having cork taint.

Question 2

What does it mean when someone says a wine is corked?

Answer 2

It likely means that there is a detectable musty, dank odor in the wine due to the presence of TCA (Trichloroanisole). In milder cases, the wine may seem muted or lacking flavor.

Question 3

What are current estimates for the number of bottles that are affected by cork taint each year?

Answer 3

Estimates range from 1-8%, and is falling due to new technology and approaches that are reducing the likelihood of TCA.

Question 4

True or False. TCA has a high recognition threshold. (There must be significant levels of TCA present to detect it.)

Answer 4

False.

TCA has an extremely low recognition threshold.

TCA can be detected in as small of quantities as 2 to 7 parts per trillion (PPT).

Question 5

What is the relationship between sulfur dioxide and the acidity levels in wine?

Answer 5

The more acidic the wine, the more pronounced the sulfur dioxide odors.

Question 6

What are the three common odors associated to sulfur compounds in wine?

Answer 6

Sulfur Dioxide - Acrid, similar to burnt matches

Hydrogen Sulfide - Rotten Eggs
Often develops when a sulfur rich wine is kept without oxygen for extended periods of time. Can also develop when wine in a barrel or tank is left to rest with the lees sediment for a long period of time.

Mercaptan - Ethyl mercaptan may form due to a combination of sulfur and ethanol. The odor is sometimes described as garlic or onion-esque. Mercaptan is added to natural gas to natural gas can be detected.

Question 7

What are two types of bacteria that can survive in wine’s acidic environment?

Answer 7

Lactic bacteria

Acetobacter

Question 8

What does acetobacter do in wine?

Answer 8

In the presence of oxygen, acetobacter converts alcohol into acetic acid.

Acetic acid has a white vinegar odor to it.

Question 9

What does “volatile acidity” refer to?

Answer 9

Volatile means ‘prone to evaporation’ in wine.

Volatile acidity in wine refers to wine with an aroma of white vinegar caused by acetic acid.

Question 10

What is the odor indicating the presence of butric acid?

Answer 10

Butyric acid produces an odor similar to that of rancid butter or spoiled cheese.

Question 11

What does ‘Brett’ refer to?

Answer 11

Brett refers to Brettanomyces, a member of the yeast family.

When present, it can cause a ‘horsy’ or ‘sweaty’ odor. The odor is sometimes described to be similar to a bandaid or medicinal in nature.

Question 12

What may cause horsy or sweaty odors in wine?

Answer 12

The presence of Brett (Brettanomyces) - a member of yeast family - can cause odors in wine including horsy, sweaty, and medicinal (band aid esque).

Question 13

Name 5 common odors that can be found in wine:

Answer 13

Brett (horsy, sweaty, bandaid, medicinal)
Green (leaves, usually a result of using underripe grapes)
Oxidized (nutty, carmelized, lack of fruit)
Maderized (cooked or baked in nature)
Moldy (Results from using moldy grapes or moldy barrels)
Rubbery (sometimes associated with low acid wines or excess sulfur)
Stagnant (stale water)
Stemmy (bitter, green odor of grape stems)
Wet Cardboard (likely caused by the presence of TCA, papery chemical odor)
Yeasty or Leesy (may result if the dead yeast cells have remained in the wine for too long. Though also intentional in some wines - e.g. sparkling wines)
Reduction or Reductive (rotten eggs, garlic, struck matches, cabbage, burnt rubber)

Question 14

What does “reductive” mean in wine making?

Answer 14

Lack of exposure to oxygen.

Question 15

True or False

Some odors can be considered favorable in small quantities and unfavorable in larger quantities.

Answer 15

True

Example: Leesy

Question 16

What can cause the smell of rotten eggs in a wine?

Answer 16

The rotten eggs odor typically indicates the presence of Hydrogen Sulfide.

This happens most often when sulfur rich wine sits too long without exposure to oxygen - or when a wine in a tank or barrel remains in contact with the lees sediment for too long.

Question 17

Why might a wine have a garlic or onion odor to it?

Answer 17

This may indicate the presence of Mercaptan.

Ethyl mercaptan may form as sulfur and ethanol combine. This is a very difficult fault to overcome.

Question 18

Why might a wine have an overly acrid smell? Similar to that of burnt matches?

Answer 18

This may indicate the presence of Sulfur Dioxide.

The sensory effects of SO2 are directly related to the pH levels of the wine. The more acidic the wine, the more pronounced the sulfur dioxide odors are likely to be.

Question 19

What may make a wine smell like sauerkraut or a goat?

Answer 19

Presence of lactic acid in a wine.

Question 20

What does “geranium fault” refer to?

Answer 20

Geranium fault refers to the odor resembling that of crushed geranium leaves.