The yogurt and milk kefir are diary drinks/food made through milk fermentation and triggered by the lactobacterial cultures only- for yogurt, and lactobacterial cultures plus yeast for kefir.
The lacto bacteria, and yeast for kefir, consumes the lactose in the milk and the side product generated during this process, called lactic acid is the one that thickens the fat globules in the milk and delivers flavour to the yogurt and milk kefir.
When making yogurt with a freeze-dried starter you need to awake the bacteria in the starter, as they are hibernating. For this, you need to make the first batch of yogurt. It will take longer than usual, but at the end it will be milder in taste and creamy.
When we make the second batch, a few spoons from the first batch are enough. Also, the time for incubation is shorter, between 3-6 hours, and the yogurt will be slightly tarter and thicker compared to the first batch.
The consequent batches will be even sourer in taste if the incubation time is longer than few hours. So, how to control the taste?
1. Always clean and sanitise the containers and utensils before use. Simply pour boiling water over and inside them or soak them in boiling water for a while.
2. Always boil the milk before using it. This will sanitise the milk, evaporate the water in the milk, and will break down some of the enzymes in the milk, which will speed up the fermentation.
3. If you wish a sourer yogurt, please allow a longer incubation. For a less sour yogurt, remove immediately after it sets.
The sourness is delivered by the increased number of lacto bacteria and level of lactic acid. The bacterial colony increases due to a longer incubation and/or higher temperature, as well as mixing with other non-yogurt bacteria present in the environment.
You can control the sharpness by simply controlling the temperature and incubation time.
If your yogurt maker does not allow you to control the temperature, then reduce the incubation time to its minimum and put the yogurt in the fridge immediately after it is set.
If you like yogurt or kefir with a sourer taste, increase the incubation temperature a bit or slightly increase the incubation time.
Please keep an eye on it to avoid over incubation and separation.
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