Valerie's Yoghurt & Yoghurt Cheese

[Thermomixer]

I think those in Spain/Portugal have made it successfully ? 

Check out the recipes following on from this post.  Basically the same temp/speed

http://www.forumthermomix.com/index.php?topic=2302.msg24876#msg24876

[versaceyoyo]

thanks for reminding us about those - the shorter time would certainly be useful if it works.  i'm going to give it a go.

[~Lauren~]

Hi All,
I've been successfully making this yoghurt for a while using pasteurised milk but today I used RAW MILK and it failed Does anyone know how I can make it work with raw milk?
Meanwhile I'll whip up some pancakes
Hoping someone has some answers for me,
Thanks,
Lauren

[Thermomixer]

The RAW factor shouldn't be a problem - you heat it well past the temp needed to pasteurise it.  It may be a problem if you use the recipes which only go to 50 deg.

Maybe the milk had a lower protein content? 

[andiesenji]

I agree with Thermomixer.   

Once the milk is heated at least to 85° C., even skim milk should produce a suitable result. 

You do have to be sure and cool it down so the temp in the entire mass is no warmer than 45° C., otherwise the heat will destroy the culture you are mixing into the warm milk. 
It can be a little cooler but absolutely not below 30° C. or the culture won't have optimum conditions in which to grow. 

[meganjane]

I've finally cracked the yoghurt making! I was so disappointed with my initial efforts, but I just wouldn't give in!
I heat the milk to 90 degrees C, then cool to 37 degrees, but I check with my (clean) finger to make sure that it's tepid, because the TMX might say 37, but it's anywhere between 45 and 37.
I add the starter yoghurt and put the TMX on for 20 minutes, but don't do Time and Temperature. The bowl stays warm for all that time and still shows 37 degrees.
While it's doing this, I place my Le Creuset lidded casserole  in the oven and heat oven to 50 C and then turn it off.
Pour milk mixture into the casserole and place in the oven for the required 8 hours or overnight. Lovely thick yoghurt.

The cast iron of the Le Creuset holds the heat so well. You probably could do the same with the Thermoserver too.

[versaceyoyo]

I tried to make the yoghurt using the 50 degree method and FAILED.  It resulted in the slime that others speak of.  Perhaps because this came from a European cook book it might indicate that they like their yoghurt at a different consistency to us?  I'm sticking with Valerie's original method as it gives me a yoghurt consistency I like.  I used the failed yoghurt (which still tasted fine) to make frozen strawberry yoghurt which was beautiful.

[meganjane]

I tried to make the yoghurt using the 50 degree method and FAILED.  It resulted in the slime that others speak of.  Perhaps because this came from a European cook book it might indicate that they like their yoghurt at a different consistency to us?  I'm sticking with Valerie's original method as it gives me a yoghurt consistency I like.  I used the failed yoghurt (which still tasted fine) to make frozen strawberry yoghurt which was beautiful.

versaceyoyo, what's the 50 degree method? I've only used 80 or 90 degrees.

[Meagan]

MJ it is the yoghurt recipe in the my way of cooking book.

[meganjane]

Oh, righto. I don't have that book. I shouldn't imagine 50 degrees would be successful either.

[versaceyoyo]

MJ There are also some other recipes on this thread from Gralke using 50 degrees. 

[meganjane]

MJ There are also some other recipes on this thread from Gralke using 50 degrees. 

Had to search to find them. I didn't read them properly when I read this thread initially, as I wasn't interested in making sweet or flavoured yoghurt, just natural.
Anyway, I'm glad you found the right method for you.

[andiesenji]

As I mentioned in an earlier post, as did Thermomixer, there is a chemical change in the milk after the pre-heating to a specific temperature, that allows the yogurt culture to change the structure of the milk solids - the casein proteins, of which there are four types in cow's milk. 
Without this process the culture can't "invade" the cells efficiently and there is the possibility that an undesirable organism (that is less fussy about the structure of the milk proteins) can propagate and produce what you describe as a "slimy" end result.

Pasteurization does not kill ALL the bacteria in milk.  There are always some organisms that are not exactly pathogenic but are also undesirable.   Without the heating to a high enough temp to inactivate these organisms, you will give them an opportunity to take over and actually prevent the development of the desirable bacteria.

Following is a quote from the California Milk Board:
"Yogurt is formed by the growth of two bacterial organisms in milk; Streptococcus thermophilus and Lactobacillus bulgaricus which turn the milk sugars into lactic acid. These are two separate bacteria that are active at different times during processing. Some times you will also find yogurt that contains other ""Probiotic"" cultures such as Lactobacillus acidophilus, Bifidobacterium longum, and Bifidobacterium infantis which are bacterium normally found in your intestines. Together these bacteria aid in digestion and the synthesis of vitamins. Here are the required steps. Heat milk to between 180 and 200 °F. Heating the milk is done for a few reasons. First, to sterilize/pasteurize the milk so that the yogurt bacteria/culture has a hospitable place to grow in. It is not desirable to incubate contaminating bacteria that might be present in the unsterilized milk. Heating should be done even with pasteurized milk to help make a smooth thick yogurt. Heating the milk also helps stop the whey from separating out quite as much. You must then cool milk to 115 °F and add yogurt culture. (If the milk is too hot it will kill the yogurt bacteria.) Stir in yogurt culture gently until dissolved. Hold temperature at 105 to 110 °F for approximately 8-10 hours. This allows your ""good"" bacteria to grow. The methods listed in the post are suitable for this. Finally, you must refrigerate the processed yogurt for at least two hours. Refrigeration help slow the continued bacterial growth. If yogurt is not refrigerated it will become sour."

[versaceyoyo]

wow andiesenji, very comprehensive - thank you for the info!

[Thermomixer]

MJ There are also some other recipes on this thread from Gralke using 50 degrees. 

Recipes here:  http://www.forumthermomix.com/index.php?topic=2340.0  and here: http://www.forumthermomix.com/index.php?topic=2339.0

But, yes - the recipe is in the new My Way of Cooking too