Alcoholic/Yeast Fermentation

Alcoholic fermentation uses yeasts to convert sugars into ethanol and carbon dioxide, producing wines, beers, and spirits.

Overview

Alcoholic fermentation harnesses the power of yeasts - primarily Saccharomyces cerevisiae - to transform sugars into alcohol. This ancient process produces beverages ranging from light ciders to complex aged wines, as well as providing the rise in bread and the base for distilled spirits.

The Science

Yeasts perform alcoholic fermentation through an anaerobic process. They break down glucose through glycolysis, then convert pyruvate into acetaldehyde and finally into ethanol, releasing carbon dioxide as a byproduct. The reaction continues until yeasts exhaust available sugar or alcohol levels become toxic to them (typically 12-15% for wine yeasts, higher for specialized strains).

Common Foods

  • Wine and beer
  • Cider and mead
  • Sake and rice wines
  • Bread (for leavening)
  • Kombucha (partial)

Tips

Sanitation is critical - unwanted microbes can spoil batches. Temperature affects fermentation character - cooler temps produce cleaner flavors, warmer temps ferment faster but may produce off-flavors. Use airlocks to allow CO2 escape while preventing oxygen entry.

Temperature Guide

  • Lager fermentation: 45-55°F (7-13°C) — Clean, crisp flavors; requires temperature control
  • Ale fermentation: 60-72°F (15-22°C) — Fruity esters develop; most common range
  • Wine fermentation: 55-75°F (13-24°C) — Varies by style; whites cooler, reds warmer
  • Cold conditioning: 35-45°F (2-7°C) — Clarifies and mellows finished beverages

Troubleshooting

Stuck fermentation
Warm slightly, add yeast nutrient, or pitch fresh yeast
Off-flavors (solvent, nail polish)
Fermented too warm - maintain proper temperatures next batch
No bubbles in airlock
Check seal; fermentation may be slow or finished
Vinegar taste
Oxygen exposure allowed Acetobacter to grow - keep vessels sealed
Cloudy final product
Cold crash, add fining agents, or give more time to settle

Required Starters

  • Saccharomyces cerevisiae (baker's or brewer's yeast)
  • Wine-specific yeast strains for different varietals
  • Wild yeast on fruit skins (for natural wines)
  • Champagne yeast for high-alcohol or sparkling beverages

Ferments Using This Method (36)