Wine

Wine is Grape juice that Fermentation has taken past must. Yeast converts much of the sugar to ethanol and carbon dioxide. What remains — acid, residual sugar, phenolics, aroma compounds — is the drink. This page is the craft skeleton. Sensory method lives on Tasting wine. Shared biology lives on the fermentation page; do not expect a second copy of microbial metabolism here.

Must, sugar, and alcoholic fermentation #

Crushed grapes are must: juice, skins, seeds, and whatever pulp the press or punch-down keeps in contact. White wines often separate juice from skins early. Red wines keep skins (and often seeds) in the ferment so color and Tannin extract. That contact is maceration — a time-and-temperature extraction, not a synonym for jam-making maceration, though both words mean “let sit in liquid.”

Alcoholic fermentation is yeast on grape sugar. It is not sourdough’s mixed LAB-and-yeast paste, and it is not cheese cultures on lactose. Same word, different habitat. Inoculated Saccharomyces and spontaneous ferments are both used; this encyclopedia will not pretend they are interchangeable recipes.

Structure, not poetry #

A useful tasting grammar is physical:

• Acidity — tartaric and other acids keep wine from tasting flat and change how tannin feels.
• Tannin — phenolics that dry the mouth by binding saliva protein ¹.
• Alcohol — weight and warmth; a fermentation product, not a garnish.
• Sugar — residual sweetness if fermentation stops or is stopped.
• Aroma — grape, fermentation esters, and later oak or bottle age.

Place is a label rule, then a climate #

In the U.S., an appellation of origin can be a country, state, county, or a delimited viticultural area (AVA) ². An AVA tells you where grapes were grown under TTB rules. It does not mandate a grape variety or a cellar method. Northern California’s teaching geographies in this atlas are Napa Valley and Sonoma County — fog, hills, and San Pablo Bay as cooling, not a winery directory.

San Francisco drinks wine. It is not, by itself, a vineyard. Aging vessels and oxygen are Aging wine.