What happens to yeast when they are exposed to low temperatures?

When yeast is exposed to low temperatures, they enter a dormant state. Yeast cells are living organisms that, like most living things, have an optimal temperature range for their metabolic activities. When temperatures drop below this range, yeast significantly reduce their metabolic activities, leading to a decrease in fermentation and cell division. In this dormant state, they do not die but essentially "pause" their activity until conditions become more favorable, such as when temperatures rise again. This characteristic is important in brewing and fermentation processes, as it allows for control over yeast activity and timing in production.

While yeast can endure low temperatures, they do not become hyperactive; instead, their activity diminishes. Similarly, low temperatures do not kill the yeast but slow down its function, and fermentation speed does not increase under these conditions. Understanding yeast behavior at various temperatures is crucial for achieving desired results in brewing and fermentation.