Wine Composition & Chemistry Flashcards
pH range of wine
2.9-3.9
TA range of wine
.5-.75%
Ester
An acid joined to an alcohol
The most common ester in wine
ethyl acetate of acetic acid & ethanol
fruit & flowers can become varnish, nail polish remover, or glue if too prevalent.
Aldehyde
An oxidized alcohol
Maderization fault if unintentional and excessive
The most common aldehyde in wine
acetaldehyde is oxidized ethanol. It gives fino sherry its nutty aroma
what promotes the release of a wine’s aromatic compounds?
dissolved carbon dioxide
most volatile acid found in wine
acetic acid
how does toasting oak barrels influence vanillin content?
On a bell curve. A medium toast barrel will have more accessible vanillin than a lightly toasted or a darkly toasted barrel
how many ppm of sulfites must be present in a wine sold stateside to require a “contains sulfites” warning?
10ppm
Official name and recognition threshold for cork taint
2,4,6-tricholoroanisole is detectable at 2-7 parts per trillion
Tactile sensation sometimes caused by sulfur dioxide flaw, and wine chemistry component that enhances its perception
Sulfur dioxide is associated with a burning sensation in the throat, in addition to the acrid smell of burnt matches. This flaw is magnified in more acidic environments
How does the hydrogen sulfide flaw occur?
In the absence of oxygen, especially in screwcap wine, or when lees rest too long in anarobic tanks or barrels, there’s a risk of excess hydrogen sulfide production and its associated odor of rotten eggs
How does the ethyl mercaptain flaw occur
when an ethanol binds to sulfur, it creates ethyl mercaptain, which smells like onion, garlic, or cabbage. This flaw is more serious and less remediable than the other sulfur flaws.
What are the major causes of bacterial faults? Why?
Acetobactor & lactic acid bacteria, some of the only two that thrive in acidic environments like wine.
What flaws are caused by acetobactor?
A vinegar aroma, volatile acidity, and ethyl acetate flaw
What’s acensense?
When acetobacter give the wine volatile acidity & excess ethyl acetate
What flaws are caused by lactic acid bacteria?
Excess lactic and butyric acid, leading to goaty and rancid butter smells, as well as the geranium flaw
What is the geranium flaw?
Excessive notes of geranium oil, crushed geranium leaves, or decaying geraniums, as a result of lactic acid bacteria’s metabolism of succinic acid.
Brett
Sweaty, horsey, or medicinal, brett is a flaw associated with brettanomyces strain of yeast
Leesy
bready notes
Green
sharp tartness from unripe grapes
Stemmy
tannic from stems & seeds
Oxidized
nutty, caramelized aroma of acetaldehyde & browning
Maderized
unintentional cooked or baked aromas overshadowing fruit
Rubbery
indicative of excess sulfur or low-acid wine
Reductive
smells associated with sulfur flaws discussed above from anaerobic environments
Wet cardboard
from use of paper filtration or TCA
Moldy
from use of moldy grapes or barrels
Stagnant
the aroma & flavor of stale water
What’s sotolon?
An impact compound primary in lovage & fenugreek seeds, resulting from oxidation in wine. Smells and tastes like cumin, maple syrup, walnuts, molasses, & roast tobacco. Common in sherry & madeira, but also aged sauternes & chardonnays & vin jaune.
