Overfermentation

Overfermentation refers to a process where fermentation continues beyond the intended endpoint, altering product characteristics after the desired fermentation stage. It can occur in foods and beverages produced by yeast, bacteria, or molds.

Causes include excessive temperature, long fermentation times, high sugar content, or contamination by aggressive microorganisms, as well as mis-timed inoculation or inadequate stopping conditions. In some systems, the fermentation phase is meant to be stopped at a defined point to preserve sweetness or texture; failure to control conditions allows ongoing metabolism.

Effects: as sugars are exhausted and byproducts accumulate, flavors become more sour, bitter, or solvent-like; acidity increases; alcohol content may rise; carbonation may become excessive; texture can soften or become mushy. Some products may develop risky levels of acidity or other compounds that affect safety or stability.

Examples: In brewing, overfermentation can lead to overly dry beers or bottle bombs in bottle-conditioned beers; in wine, it can produce very high alcohol or overly dry profiles; in dairy products like yogurt, overfermentation yields a very tart, tangy taste and thick texture; in fermented vegetables, it yields extreme sourness and texture changes.

Management: prevention includes careful monitoring of temperature, sugar availability, and fermentation timing; quick cooling to halt fermentation; adjusting pH; selecting appropriate strains; in bottling, ensuring complete but controlled primary fermentation and proper conditioning.