Boiling of the milk when making yogurt and kefir at home
Many people hesitate to boil the milk for different reasons, however, what are benefits of boiling when you make yogurt and kefir at home?
The boiling of the milk kills competitive bacteria in the milk—this guarantees that there is no number of competitive bacteria present. Most of the milk nowadays is pasteurized in advance before reaching the shelves in the shop as the focus is on removing the bacteria harmful to people, but small numbers of bacteria still exist after the process. They are not harmful to people but they might get into competition for food with the yogurt and kefir bacteria in the starter. This will increase the time for incubation and also will compromise the starter in the long run, which consequently will reduce the number of recultivations.
Boiling of the milk evaporates the water in the milk. All processed (shop bought) milks contain water. After fermentation you will notice some whey left. This whey actually is the water in the milk and the best way to remove this in advance is to boil the milk for 15-20 min.
The boiling also breaks down some enzymes in the milk and thickens the solids. This additionally supports the thickening of the milk during fermentation and practically helps the lactobacteria in doing the job, further reducing the incubation time.
There are two main ways to boil the milk
On the stove—this is actually the way people try to avoid. It takes time and needs constant attention as the milk can burn or overflow, especially if trying to maintain a long boiling process.
In the microwave on full power for 15-20 min.—This way is one of the easiest. You need a flat container sized at least double the amount of milk to avoid overflow and nothing else.
Many people also wonder if they should boil ultra-pasteurised milks. The answer is simple: not every time, but if you made a yogurt and there are excessive amounts of whey, please do it for the next batch.
For the specific instructions and step by step tutorials, please refer to our website, blog, forum, watch the other YouTube videos, or download the Yogurt App.