Ch 2. Wine Faults Flashcards
- Recall the main terminology associated with wine faults - Describe the source and effect of cork taint - Discuss the impact of sulfur compounds on wine - Recognize which odors are acceptable and under which conditions
Where is a wine’s distinct scent derived from?
- Grapes
- Fermentation processes
- Aging
- Oxidation
- Contact with oak
What does cork taint smell like?
Musty and moldy, like a ‘dank basement’
True or false:
Infected corks are the only source of cork taint.
False
What causes cork taint?
A mold that can grow on and in the bark of the cork oak tree, winemaking implements, or the winery itself, which interacts with other compounds to generate 2,4,6-trichloroanisole (TCA). TCA can leach from a cork and into the wine or become present in wine from other sources.
What effects does cork taint have on a wine?
Unpleasant, moldy odor.
In mild cases, the wine tastes muted or less flavorful.
True or false:
TCA is not harmful to ingest.
True
True or false:
TCA is not highly persistent.
False
True or false:
TCA cannot be transferred into wines that are sealed with screw caps or artificial corks.
False
How many bottles are affected by cork taint annually?
1 - 8%
TCA has a ___ recognition threshold and is noticeable at very ____ concentrations.
TCA has a LOW recognition threshold and is noticeable at very LOW concentrations.
Most people can detect TCA at concentrations of __ to ___ parts per ___.
Most people can detect TCA at concentrations of 2 to 7 parts per TRILLION.
True or false:
Sulfur can produce strong off-odors.
True
What is sulfur dioxide?
A preservative, the most common form of sulfur in wine.
What does sulfur dioxide smell like?
Acrid, burnt matches.
What impacts the sensory effects of sulfur dioxide?
pH
The ____ acidic the wine, the ___ pronounced the sulfur dioxide will be.
The MORE acidic the wine, the MORE pronounced the sulfur dioxide will be.
What are the 3 forms of sulfur that can produce odors?
- Sulfur dioxide (SO2)
- Hydrogen sulfide (H2S)
- Mercaptan
What is hydrogen sulfide?
A colorless gas formed by sulfur compounds in the complete absence of oxygen.
What does hydrogen sulfide smell like?
Rotten eggs
What is the most typical way hydrogen sulfide is formed during winemaking?
When a barrel or tank of wine rests for a long time with a large amount of yeast sediment in the bottom.
Why can hydrogen sulfide be a problem for wines closed with screw caps?
Because screw caps are impervious to oxygen.
What is ethyl mercaptan?
A sulfur-ethanol compound of that is very malodorous and ruins a wine if developed.
What does mercaptan smell like?
Garlic or onions
True or false:
Mercaptan is the odor added to odorless natural gas to help people detect a leak.
True
What form of sulfur is mercaptan most easily confused with?
Hydrogen sulfide
True or false:
Mercaptan is not serious and can be easily remedied.
False
What are the most common bacterial-related odors?
- Acetic acid
- Butyric acid
- Lactic acid
- Geranium
Which 2 bacterias can survive in the acidic environment of wine?
- Lactic bacteria
2. Acetobacter
Which bacteria are responsible for malolactic fermentation?
Lactic bacteria
Which bacteria can convert alcohol into acetic acid?
Acetobacter
How does bacteria attacking chemical compounds in the wine affect the wine itself?
It can:
- change the composition
- produce carbon dioxide or other gases
- produce unpleasant odors
What does acetic acid smell like?
Vinegar
What does ‘volatile acidity’ reference?
A wine with a decided roma of white vinegar caused by acetic acid.
What does ascensence?
A fault evidenced in a wine with discernible volatile acidity accompanied by a high level of ethyl acetate.
What does Butyric acid smell like?
Rancid butter or spoiled cheese
What does lactic acid smell like?
Sauerkraut or goat
What does ethyl acetate smell like?
Fingernail polish remover or model airplane glue
What does geranium smell like?
Crushed geranium leaves
What causes the geranium odor?
Incomplete malolactic fermentation
What is Brett short for?
Brettanomyces
Where is Brett derived from?
Yeast
True or false:
Brett can infect winery and potentially all of it’s wines made there.
True
What does Brett smell like?
Band-Aid, medicinal, sweaty, horsy
What can Brett do to a flavor of a wine?
It can deaden the primary flavors
What does a ‘green’ odor smell like?
leaves
What is a ‘green’ odor usually from?
Use of immature or underripe grapes
What chemical occurs from oxidative reactions?
Acetaldehyde
What does acetaldehyde smell like?
Nutty, caramelized
What color can oxidation turn wine?
Brown
What does maderized wine smell like?
Cooked or baked
How do wines become maderized?
From excessive heat or oxidation
True or false:
Maderized wine is generally considered to be a fault.
True
What does a moldy odor result from?
The use of moldy grapes or moldy barrels
The odor of rubber can be caused by ____ acid or ____ sulfur.
The odor of rubber can be caused by LOW acid or EXCESS sulfur.
What does a ‘stagnant’ odor smell like?
Stale water
What does a ‘stemmy’ odor smell like?
Bitter, green odor of grape stems
What does a wet cardboard odor result from?
Cork taint or misuse of filter pads or filtering materials
What does a yeasty odor result from?
Dead yeast cells in contact with the wine for too long
True or false:
It is not acceptable for sparkling wines to smell yeasty.
False
True or false:
It is acceptable for wines intentionally aged ‘on the lees’ to smell yeasty.
True
What odors can the term ‘reduction’ refer to?
Rotten eggs, garlic, burnt matches, cabbage, burnt rubber
What is a reductive condition?
A condition that lacks oxygen
