So I know you can't use UHT milk to make cheese, because of the way the proteins get denatured at that temperature. But can you use it to make yogurt?
I just tried making yogurt with UHT Lactose-free milk (my kids and I are lactose-intolerant and there are few yogurt options where I live). It worked for me, but as mentioned in a couple of the answers here, I added powdered milk. (1 cup milk + 2 tbsp milk powder + 1 tbsp plain yogurt with live culture)
To test whether I need to heat the milk or not, I experimented and did one jar with heated UHT milk, and one jar with room temperature UHT milk. The heated batch was definitely thicker and creamier, but I suspect it has to do with some moisture loss during the heating process itself. I measured 1 cup of the milk into the saucepan, and one cup straight into the jar. After heating, the volume of the milk was (expectedly) smaller, so that's one hint right there as to why it's thicker and creamier.
The other things I did which, I believe, helped with the successful outcome were: (1) to keep the jar immersed in water that was at 100F, instead of 115F (the usual recommended temp) and did so for 8 hours; (2) I took the extra step of straining the yogurt for 2 hours.
So yeah, I was able to make thick, creamy Greek-style yogurt with UHT milk.
I agree with Jackie - just add a little powdered milk. I've been using unheated UHT milk to make yoghurt for years, with fab results. I've also made cheese quite a few times with it. I've made yoghurt with pasteurized milk as well and the results were the same, just less convenient than UHT if you live in the boonies like me.
If you want to know how yoghurt and cheese are made, I suggest you get a book (yes, libraries still exist) and ignore the massive amount of 'evidence' on the internet.
And just 2 more points:
1) Greek yogurt is made by straining the whey from regular yoghurt. Even in Greece (I lived there).
2) making yoghurt is a bit of trial and error. never assume you don't like something after trying it only once. you'll need to tweak lots of things until you get it right (kind of like making the perfect loaf of bread).
yes you can, I do it all the time now. I have tried many different UHT types, the following are my experiences. I only used the full cream UHT type, I don't boil the milk, I just add some farmers union greek yoghurt to it and give it a shake, then start incubating.
Woolworthes UHT milk makes the thickest yoghurt.
Devondale UHT milk makes ok yoghurt.
foodland/coles UHT milk makes less thick yoghurt
Pauls UHT milk makes very runny yoghurt
I have been making yoghurt from full fat Devondale UHT for 4 years. The results are usually excellent, though I recommend allowing the cycle to run a bit longer for thicker results. I use an instant pot to boil and then ferment the milk for a bit more than 8 hours. I often start the process a little bit hot, as I can't be bothered to wait for the boiled milk to reach room temperature. I believe that the starter culture makes a big difference. I have used a cheap Chinese culture (probably targeted at making yoghurt drinks) and two Danisco professional cultures (Yo-Mix 495 LYO 250 DCU and 883 LYO 50 DCU). The 495 seems to be targeted at making Greek and does indeed produce a thicker, creamier, slightly less sour yoghurt. I normally reuse some of the existing yoghurt to make the next batch, so buying good culture is worth it. The ultimate thickness of the Greek yoghurt I make depends more on the straining process (I often leave it until all the weigh is separated as I like yoghurt cheese and the weigh is good in smoothies). I haven't tried making the yoghurt without boiling; this is something that I intend to try since it would reduce the process time by about 4 hours (I make 5L batches).
I have been making home-made yogurt for a month on an every-day basis.
I tried UHT once and it was extremely watery and flaky that I threw it away.
I have since sticked with fresh (skimmed/semi skimmed/whole) milk, which works perfectly.
I do notice that different brand of milk give a different texture too.
Puzzled, I searched on Google trying to find an answer why UHT milk can't be used, and found this. I do not have an answer myself but I thought it is helpful to share my own experience with making yogurt.
My mother used to make yogurt with UHT milk. But as Lorenzo said before, it doesn't have any bacteria. That's the reason why my mother used to add a little quantity of an existing yogurt in the mix of milk and sugar. Afterwards she put it in the yogurt-maker for a few hours and tada! you've got your homemade natural yogurt!
As Gapton says, the resultant yogurt is more watery (texture doesn't anything to do with greek yogurt for example), that is right, but I love it!! it is very natural, it's my childhood yogurt and I am still alive ;)
Hope this helps!
Btw, happy pancake day!!
I have made excellent thick yoghurt with uht semi skimmed milk, for every 3 cups milk add 1 cup of skimmed milk powder and a couple of tablespoons of live yoghurt from fridge. I use my easiyo to make (I started with one of the packet mixes and used the yoghurt made to supply the 2 tablespoons - then I use the next batch to start a new one) works brilliantly. I use cup cake flavouring and stevia sugar to sweeten. Not fat free but low, thick and delicious and full of good bacteria. Tip - freeze some berries (I chop up grapes, strawberries, raspberries, blueberries and banana and put in single portion bags). When fully frozen tip into bowl and add 3-4 large spoons yoghurt above, stir in. Leave for 2 mins and yoghurt hardens. Just like having chunky icecream - I have daily yum!
I have used UHT skim along with powdered skim in my yogurt for years. Heres why 1. it works 2. it saves sterilizing the milk, I'm a rational male 3. its actually a little cheaper 4. I've read concerns that heat treating whole milk causes oxidation to cholesterol which has health implications, so skim all but eliminated the cholesterol. This may be wrong