As an experienced sommelier and brewer, I can tell you that freezing yeast is generally not recommended. While freezing yeast won't necessarily kill it, it can potentially damage the cells and affect their viability. However, there is a method called freeze-drying that can be used to preserve yeast, but it requires specialized equipment and knowledge.
Freezing yeast can cause the water inside the cells to form ice crystals, which can rupture the cell walls and membranes. This can lead to a loss of cell viability and ultimately affect the yeast's ability to ferment properly. Additionally, freezing yeast can also lead to changes in the yeast's metabolism and overall performance.
On the other hand, freeze-drying is a process that involves removing moisture from the yeast while it is frozen. This method can preserve the yeast for long periods without affecting its viability. Freeze-dried yeast can be stored at room temperature and rehydrated when needed for brewing. However, freeze-drying requires specialized equipment and is not something that can be easily done at home.
Personally, I have used freeze-dried yeast in my brewing experiments, and I find it to be a convenient and reliable option. The yeast remains dormant until rehydrated, and it exhibits good fermentation performance. It's important to note that not all yeast strains are available in freeze-dried form, so it's essential to check with your yeast supplier to see if they offer this option.
If you find yourself in a situation where you need to preserve fresh yeast and don't have access to freeze-drying equipment, the best alternative is to store it in a sealed container in the refrigerator. The ideal temperature range for yeast storage is between 36-42°F (2-6°C). This temperature range helps to slow down yeast activity and prolong its viability.
To summarize, while freezing yeast can potentially damage the cells and affect their viability, freeze-drying is a viable method for preserving yeast long-term. If freeze-drying is not an option, storing yeast in a sealed container in the refrigerator is the best alternative. Regardless of the method used, it's important to check the yeast's viability and vitality before using it for brewing to ensure optimal fermentation performance.
