What phenomenon can occur due to a lack of nutrients in yeast during fermentation?

Autolysis is a phenomenon that occurs when yeast cells die and begin to break down, typically due to nutrient depletion during fermentation. Yeast cells require essential nutrients, such as nitrogen, vitamins, and minerals, to remain healthy and active throughout the fermentation process. When these nutrients are not sufficiently available, the yeast can struggle to maintain its viability, leading to cell death.

As yeast undergoes autolysis, they release enzymes that can break down cellular components, including proteins and other compounds. This can contribute to changes in the beer's flavor and aroma, potentially leading to off-flavors if the autolysis is significant. Therefore, autolysis is directly linked to nutrient deficiency in yeast and serves as a critical consideration during fermentation to ensure healthy and complete yeast activity.

The other options relate to different fermentation phenomena that occur under specific conditions, but they do not directly relate to the consequences of nutrient deficiencies in yeast. Flocculation refers to the clumping of yeast cells during fermentation, diacetyl production is a flavor compound that can result from yeast activity and improper handling, while carbon dioxide accumulation is a normal byproduct of fermentation facilitated by healthy yeast. None of these specifically denote the breakdown of yeast due to nutrient lack, making autolysis the