Probiotics in consequent batch - Customer Question.
Q: Hello - I purchased your Bulgarian yogurt probiotic starter. I make each yogurt batch from a bit of the previous batch. I only use fresh milk, dry milk and the starter to make a litre in my electric yogurt maker, so each batch is relatively pure. I am now making a fifth generation yogurt from the original batch that was started with the sachet. My question is: are there still strong probiotics in the fifth generation batch? or are they weakened or diluted from re-culturing? Thank you, very pleased with your product.
A:Hello ***************
Thank you for your email.
The amount of the active bacteria will reflect on the quality of the yoghurt as the following formula is valid - Less amount of bacteria = low-quality yoghurt. If you manage to re-culture 5 batches and quality is fine - this mainly mean that you can keep going up to the point that yoghurt quality becomes poor.
In fact, the quality of bacteria is higher in re-cultured batches, as they can feed on milk and lactose- so the food is enough.
A number of bacteria in the sachets is intentionally low and they are just a few billion because there is no enough food for more in the sachets and they would die quickly with no food. Once you manage to make the first batch the number of bacteria increases greatly and you can see this as the recultivation become an easy and quick process.
Please note also that at some point the yoghurt will become too sour.
This will notify you that a number of bacteria is very hight and soon the food provided in the milk will not be enough. You can manage this when reducing the incubation time. So if you reculture for 6 hours now reduce to 5 for the next batch and then to 4… to 3 hours until the yoghurts become too sour or separate.
Should I boil the milk?
Q: I will like to know why we need to boil the milk first, I was doing research on it and they didn’t say that the whole milk has to be boiled first.
Can you clarify for me, please?
Thanks,
A:The starter contains bacteria which need to trigger fermentation with milk. The bacteria will do this successfully in case that the milk provides all nutrients which bacteria need. There is another factor here. All milk contains bacteria(mostly considered as bad ( it can harm the body) or neutral(it cannot harm the human body and health).
However, when you make kefir you need to consider if those bad or neutral for the human bacteria can harm the kefir bacteria.
In most cases, the milk in the store is processed and a number of the bacteria dangerous for the humans are removed, but in any milk, there are still bacteria which are neutral and cannot affect the humans but can affect the kefir bacteria which can result in the quality of the kefir.
They also can gradually contaminate the ready kefir reduce the benefits and ability to re-culture.
This is not valid for all brands. But as the quality of the milk varies throughout the year it is difficult to say what milk is good for the bacteria and what is bad.
Please always check the milk you choose for preservatives. The good milk does not contain any. Second always boil this milk as the number of competitive bacteria might be too hight which can compromise the culture and the kefir at the end.
The majority of the people and those who create content about yogurt and kefir actually boil the milk, however, they skipped the explanations as boiling is accepted as a default condition.
Every time when you work with bio culture you need to make your best and kept them away for competitive bacteria which are everywhere.
There is another reason to heat the milk besides killing off any pathogens that might out compete the starter bacteria. It has two additional benefits. First, it serves to reduce the water content in the milk. Secondly, the elevated temperature also causes the proteins to unfold. The benefits of less water and denatured proteins is a smoother custard like texture in the final product. When I lived in the Middle East back in the 1960’s the milk was heated in long shallow pans until the volume was reduced by half. I don’t try to reduce the volume that much, I heat the milk to just before it boils, to about ~90°C for about 20 minutes. If I want thicker yogurt, I just strain out some of the whey. Or to really splurge, I will use Half&Half or even double or triple cream. If you can find a local source for grass-fed organic whole milk, trust me. It’s worth the cost.
Hi George,
You can store it in the fridge for a few days as in this way the cultures don’t multiply anymore rapidly.
The best way is to follow the tips in the instructions received on your email and to freeze a few spoons in the ice cube trays and keep them in the freezer.
Once you are ready for a new batch, unfreeze them at room temperature and mix with milk, then as usual