Wine Composition & Chemistry

Question 1

pH range of wine

Answer 1

2.9-3.9

Question 2

TA range of wine

Answer 2

.5-.75%

Question 3

Ester

Answer 3

An acid joined to an alcohol

Question 4

The most common ester in wine

Answer 4

ethyl acetate of acetic acid & ethanol
fruit & flowers can become varnish, nail polish remover, or glue if too prevalent.

Question 5

Aldehyde

Answer 5

An oxidized alcohol
Maderization fault if unintentional and excessive

Question 6

The most common aldehyde in wine

Answer 6

acetaldehyde is oxidized ethanol. It gives fino sherry its nutty aroma

Question 7

what promotes the release of a wine’s aromatic compounds?

Answer 7

dissolved carbon dioxide

Question 8

most volatile acid found in wine

Answer 8

acetic acid

Question 9

how does toasting oak barrels influence vanillin content?

Answer 9

On a bell curve. A medium toast barrel will have more accessible vanillin than a lightly toasted or a darkly toasted barrel

Question 10

how many ppm of sulfites must be present in a wine sold stateside to require a “contains sulfites” warning?

Answer 10

10ppm

Question 11

Official name and recognition threshold for cork taint

Answer 11

2,4,6-tricholoroanisole is detectable at 2-7 parts per trillion

Question 12

Tactile sensation sometimes caused by sulfur dioxide flaw, and wine chemistry component that enhances its perception

Answer 12

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

Question 13

How does the hydrogen sulfide flaw occur?

Answer 13

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

Question 14

How does the ethyl mercaptain flaw occur

Answer 14

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.

Question 15

What are the major causes of bacterial faults? Why?

Answer 15

Acetobactor & lactic acid bacteria, some of the only two that thrive in acidic environments like wine.

Question 16

What flaws are caused by acetobactor?

Answer 16

A vinegar aroma, volatile acidity, and ethyl acetate flaw

Question 17

What’s acensense?

Answer 17

When acetobacter give the wine volatile acidity & excess ethyl acetate

Question 18

What flaws are caused by lactic acid bacteria?

Answer 18

Excess lactic and butyric acid, leading to goaty and rancid butter smells, as well as the geranium flaw

Question 19

What is the geranium flaw?

Answer 19

Excessive notes of geranium oil, crushed geranium leaves, or decaying geraniums, as a result of lactic acid bacteria’s metabolism of succinic acid.

Question 20

Brett

Answer 20

Sweaty, horsey, or medicinal, brett is a flaw associated with brettanomyces strain of yeast

Question 21

Leesy

Answer 21

bready notes

Question 22

Green

Answer 22

sharp tartness from unripe grapes

Question 23

Stemmy

Answer 23

tannic from stems & seeds

Question 24

Oxidized

Answer 24

nutty, caramelized aroma of acetaldehyde & browning

Question 25

Maderized

Answer 25

unintentional cooked or baked aromas overshadowing fruit

Question 26

Rubbery

Answer 26

indicative of excess sulfur or low-acid wine

Question 27

Reductive

Answer 27

smells associated with sulfur flaws discussed above from anaerobic environments

Question 28

Wet cardboard

Answer 28

from use of paper filtration or TCA

Question 29

Moldy

Answer 29

from use of moldy grapes or barrels

Question 30

Stagnant

Answer 30

the aroma & flavor of stale water

Question 31

What’s sotolon?

Answer 31

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.