Glossary
Honey that has undergone fermentation, developing a sour, yeasty, or alcoholic taste and aroma. Fermentation in honey occurs when osmophilic yeasts (particularly Saccharomyces rouxii and Zygosaccharomyces species) reproduce in honey with moisture content above 18.6 percent, converting sugars into alcohol and carbon dioxide.
Pure, properly ripened honey with moisture content below 18 percent is effectively preserved indefinitely by its osmotic pressure (high sugar concentration prevents microbial growth). However, if moisture content exceeds 18.6 percent, either from premature harvest, condensation, or absorbing humidity from the environment, osmophilic yeasts can begin reproducing.
Signs of fermentation include a sour or alcoholic smell, visible bubbling or foam on the surface, a slightly fizzy taste, and a thinner consistency than normal. Early fermentation produces a pleasant, mead-like character. Advanced fermentation produces vinegar-like sourness.
Mildly fermented honey is safe to eat and some people enjoy the slightly tangy flavor. For cooking and baking, mild fermentation has minimal impact on the finished product since the alcohol evaporates during heating.
If you do not enjoy the flavor of fermented honey, it has several excellent alternative uses: use it as a base for mead making (the fermentation is already started), use it as a marinade ingredient (the acidity tenderizes meat), add it to salad dressings, or use it in a honey vinegar recipe.
Generally yes. The fermentation organisms in honey (osmophilic yeasts) are not pathogenic. Mildly fermented honey is safe for healthy adults. However, honey that has developed mold, or honey that smells strongly of vinegar, has progressed beyond simple fermentation and should be discarded.
Pasteurization (heating to 160 degrees Fahrenheit for 2 minutes) kills the yeasts and stops fermentation. However, this destroys the enzymes and beneficial compounds in raw honey. Prevention is better: store honey in sealed containers to prevent moisture absorption, and ensure honey is properly ripened before harvest.
Paradoxically, yes. When honey crystallizes, the glucose crystals that form contain less water than the surrounding liquid fraction. This concentrates water in the remaining liquid phase, potentially raising its moisture content above the fermentation threshold. This is why crystallized honey sometimes ferments while the same honey stayed fine in liquid form.
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