Glossary
The metabolic process by which microorganisms (primarily osmotolerant yeasts of the genus Zygosaccharomyces) convert sugars to alcohol and carbon dioxide. In the context of honey, fermentation occurs when the moisture content rises above approximately 19 percent, providing enough available water for yeast activity.
Properly harvested honey (below 18.6 percent moisture) does not ferment because its water activity is too low for yeast growth. However, honey that is harvested too early (from uncapped cells), improperly stored (absorbing atmospheric moisture), or diluted can exceed the moisture threshold that allows dormant yeast spores to activate.
Signs of fermented honey: tiny bubbles on the surface, slightly alcoholic or sour smell, a foamy or frothy layer, and expanded container volume. Lightly fermented honey is not dangerous but tastes off and may continue to ferment.
Mead is humanity's oldest alcoholic beverage, made by intentionally fermenting honey diluted with water. Wine yeast (Saccharomyces cerevisiae) converts honey sugars to alcohol over weeks to months. The resulting beverage ranges from dry to sweet, still to sparkling, and from 8 to 18 percent alcohol.
The distinction: accidental honey fermentation is undesirable and preventable. Intentional mead fermentation is an ancient, sophisticated craft that transforms honey into a remarkable beverage.
Fermented honey is not toxic, but it tastes sour and alcoholic. The yeast produces alcohol and CO2 but not dangerous compounds. However, advanced fermentation creates unpleasant flavors. Lightly fermented honey can be used in cooking (heat kills the yeast and evaporates alcohol) or used to start a batch of mead.
Harvest only capped honey (bees cap cells when moisture is correct), verify moisture content with a refractometer (below 18.6 percent), store in airtight containers, and keep at stable room temperature. Properly stored honey with correct moisture does not ferment.
Yes. Honey that has begun spontaneous fermentation can be diluted further and pitched with proper wine yeast to make mead. The wild yeast may produce off-flavors, so adding a strong culture of wine yeast will dominate and produce cleaner results.
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