Why yoghurt comes out different every time?
When I make yoghurt at home the result is different every time even though I follow exactly the same procedure:
- Bring a gallon of milk to 85°C
- Cool to 43°C
- Add yoghurt culture from the previous time
- Keep it at 43°C for 2-3 hours or until ready
- Cool it to refrigerator temperature
Milk is always of the same kind from the same store (Costco). I use thermometer and keep the temperature with 1°C precision.
Sometimes it is extremely creamy, soft, homogeneous, and almost sweet, and sometimes a lot of whey forms on top and it becomes very sour.
Obviously I like the the former outcome rather than latter one.
I can't figure out what is wrong, why it is different every time?
I also noticed that when I start with the store-purchased culture the first batch is likely good (creamy).
Best Answer
The explanation is easy, the correction isn't.
Bacterial growth is an exponential process, but with all the environmental variables, you get even more trouble than a simple exponential. Tiny changes in the initial conditions can result in completely different end states. What you are seeing in the "sour" state is either too much bacterial activity for your taste, or activity from the wrong kind of bacteria - thermophilic cultures produce a more sour yogurt than mesophilic ones.
Note that the low-sourness state is not obviously the preferable one, and your recipe may well have been geared towards producing the sour state.
The way to getting to the exact result every time is to be more consistent in the initial conditions. A laboratory works with much higher precision than what you describe, not only in temperature but also in selecting the culture type and the culture density and reinoculating with pure culture.
Your best chance here would be to try using lower temperatures and see if it gets better. If you can find a temperature in which you can get the creamy style yogurt consistently, great. If not, you might need to find other ways to ensure precision, such as using a commercial culture and not reusing your own.
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Why does my yoghurt separate?
It looks like water, but it isn't just water. That liquid that separates out from your yogurt is called whey. And it is completely normal for the whey to separate out from the \u201csolid\u201d yogurt. When yogurt is made (both regular yogurt and Greek yogurt), milk is mixed with special bacterial cultures.What happens if you ferment yogurt too long?
Also, the longer you let a yogurt culture, the more tart it will be. But if you let it ferment too long, the yogurt will begin to separate into curds (solids) and whey (liquid).Why is my homemade yogurt not setting?
The Takeaway. If your yogurt doesn't set up properly the first time, try treating the failed \u201cyogurt\u201d like milk, and starting over. (Reheat it, add new starter, and incubate again.) The texture may suffer some, but it can save you having to throw the whole thing away.What happens if you overheat milk when making yogurt?
Yogurt that lumps or leaks whey is often caused by culturing too hot or too long. To prevent lumpy yogurt hold the milk above 195\xb0F / 91\xb0C for ten minutes before cooling and culturing. Yogurt starter cultures containing Lactobacillus Casei generally result in thicker smooth yogurt.Yogurt Is More Unhealthy Than You Think
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