Author Topic: Yoghurt - heating milk to 82C  (Read 310 times)

Offline Tomek

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Yoghurt - heating milk to 82C
« on: October 29, 2015, 06:15:14 AM »
Hi there,

I found a recipe for yogurt. It says to first heat the milk to 82C and then cool it to 46C degree and then add starter culture. Why milk is heated to 82C degree?. Can I simply heat to 46C and add starter culture. I use pasteurized milk.

Regards
Tomek

Offline Mermaid

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Re: Yoghurt - heating milk to 82C
« Reply #1 on: October 29, 2015, 07:59:46 AM »
Hi Tomek. I follow this same heating regimen for yogurt. I believe the high heat kills bacteria in the milk, and leaves a blank slate of sorts, so that when you add the culture those are the only cultures that will be in your yogurt (no natural starter culture remains).

I think if you added your culture without heating the milk you might not get a good set (it might be a little liquidy) OR it could over acidify and have whey off and be sour tasting. Just my guess.

I heat to 82 C for 30 min and then cool to 43C to add the culture. I let the culture sit for 10 min before pouring into containers.
Then I keep it warm at about 41C for 4 of 5 hours before cooling the air space to 2C.

Hope that helps!

Online awakephd

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Re: Yoghurt - heating milk to 82C
« Reply #2 on: October 29, 2015, 09:22:32 AM »
As I understand it, the high heat is less for pasteurization than it is for denaturation of the proteins. For making typical cheese, this would be the last thing you would want to do ... but for making yoghurt, it gives you a much thicker final product. Essentially, as I understand it, this way you get the proteins that you would get from whey ricotta along with the other proteins that you would get if you didn't denature the milk.

All I can say is that it really seems to work -- I heat my milk to 180°F (83°C) and hold it there for 30 minutes, then cool rapidly by putting the container in a sink with cold water around it to around 115°F (46°C), add the starter, and incubate overnight at around that temperature. (I use an inexpensive yogurt maker for the last step, so I am not sure exactly what temperature it holds.)

VERY IMPORTANT: In the morning, put the yoghurt in the refrigerator with as little disturbance as possible -- do not stir it at this point, or it will tend to separate badly. Don't ask me how I know this ... :)

If you want REALLY thick yoghurt, start with whole milk and/or add extra cream. The results are incredibly good! Note that because I use whole milk, I do not add any powdered milk -- I think that is mostly to try to add protein/thickness to a low- or no-fat yoghurt.
-- Andy

Offline Tomek

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Re: Yoghurt - heating milk to 82C
« Reply #3 on: October 29, 2015, 09:39:49 AM »
Thanks guys. All clear ;)

Offline Stinky

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Re: Yoghurt - heating milk to 82C
« Reply #4 on: October 29, 2015, 01:11:36 PM »
Awake is correct, as far as I know. Heating denatures proteins, and gives it a creamier texture, I believe, as something about the bonds and I can never remember. And the casein matrix. But yes.
It's probably a pathogen.

Offline Schnecken Slayer

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Re: Yoghurt - heating milk to 82C
« Reply #5 on: October 29, 2015, 11:58:04 PM »
It is also why they heat milk to 64C for making coffee, it changes the protein structure and flavour.
-Bill
One day I will add something here...

Online awakephd

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Re: Yoghurt - heating milk to 82C
« Reply #6 on: October 30, 2015, 09:14:17 AM »
Interesting -- I never thought about that with making coffee!
-- Andy