Yogurt gurus - why heat milk?

[homeycow]

I make yogurt by the gallon because all the critters around here get a daily dose of it (dog, pig, cats, chickens, guineas, goose). I have been making it for years. But I have always wondered something. If I am using pasteurized milk, why do I need to heat it? Isn't pasteurized milk already heated to a very high temp? So why am I doing it again? I would love to be able to skip the heat, then cool step.

(Just FYI, here's how I make it. I pour milk into quart canning jars and heat to at least 180 degrees in the microwave. Then I cool to about 112, add my starter, put lids on the jars, put on a heating pad set on low and cover with a towel for about 8 hours. This is how I was taught and have never had a failure that I can remember.)

Thanks to anyone who can enlighten me!

 

[ranchhand]

In an effort to find out the answers, I am shamelessly bumping this thread.

I have just recently gotten interested in making yogurt and need to learn more.

Miss Prissy has a good primer in the Recipes, etc. section and I am studying it as I go.

 

[BettyR]

I thought the same thing so I tried it once with a small batch and it turned out terrible. It didn't set up at all and my yogurt is usually very thick and it tasted nasty. I tossed it out. I will never try that again.

 

[seymore0626]

I think the heating changes the proteins.

I use raw milk that has bee skimmed;

heat to 186 and hold for 30 minutes
cool to 112
add starter and whisk well
turn the oven on to 175
wrap the jar in a towel
turn the oven off (oven is on just long enough to wrap the jar)

I leave it until it sets up usually about six hours.

It makes perfect, thick, custard style yogurt every time, and we do several batches/week. I made two gallons last Friday!!!

 

[bigmike&nan]

Heating the milk kills any "non-yoghurt" bacteria. No wonder that one persons yoghurt tasted nasty...

http://hubpages.com/hub/How_to_make_your_own_yogurt_-_An_illustrated_guide

 

[featherz]

I never heat the milk other than the 100 degrees or whatever used for incubating my yogurt. Then again, I use dry milk and probably less chance of bacteria that way.

 

[Catstar68]

I sterilize the jars and utensils.
Heat the milk to 185-195 degrees and hold for 10 minutes
cool it to 120 and add the starter.
Pour into jars, cover with lids and tighten
put jars in little igloo cooler and pour 120 degree water in to the bottom of the lids. let sit overnight.
I recently tried using greek yoghurt for the starter and it turned out great. I use 2/3 cup or regular greek yoghurt from the supermarket mixed in a cup of the 130 degree milk.
If I use 2% I usually add some powdered milk, about 2/3 - 1 cup per gallon.

 

[homeycow]

Quote:
Ooooh, BettyR, thanks for being the guinea pig on that experiment! Every time I make it, I think I should try a bit of it without heating, then I just end up doing it the way I know will work. I guess I've just been too chicken

 

[homeycow]

I just realized I don't know how to quote different people's comments all in one post...so my apologies for making one post after the other.

Seymore0626, I suspect you are right about the proteins. I wish I could get raw milk. We used to drink raw goat milk and it was delicious. I always felt good giving it to my granddaughter.

Featherz, back in my low fat days, I made my yogurt with non-fat powdered milk and never heated it. I admit that was easier, but nowdays, I like fat!

I see everyone makes their yogurt a little bit different. I guess that goes to show us that it is not an exact art. Thanks to all who responded.