My girlfriend and I make a large batch of yogurt every week, and have done so for more than a year now - we just eat a ton of the stuff. THis leaves a lot of leftover whey which we used to just throw out. This past week I took my first swing at making mozzarella, and noticed that the recipe suggested not throwing out the whey, but rather using it to make ricotta by boiling it. I ended up throwing out the whey from the mozzarella anyways because it was a tiny batch, and we had to make yogurt anyway.

So, we made the yogurt, and my girlfriend saved they whey for me. I've been simmering it for a few minutes now, and it doesn't appear to be working. Nothing is curdling. I'm wondering if its a function of not having anything acidic in it? I tried adding a quarter teaspoon of citric acid, but still nothing is curdling. At this point I'm curious to play with it, so I may try simmering it all the way down into gjetost.

So really i guess my question is, outside of being less acidic, is whey from making yogurt different from whey from cheese making?

Also as a note, we use 1% milk.

4 Answers 4


Yogurt whey cannot be used to make ricotta.

With most cheeses, including mozzarella, the milk isn't boiled. The casein proteins are bound up with some of the lactose and almost all the fat to make the curd. The whey for such cheeses contains the rest of the lactose, tons of vitamin B, and almost all the albumin.

The albumin proteins are water soluble when they haven't been denatured. They also denature at a higher temperature than the casein does. Therefore, they almost all wash out of the curd with the whey. Bringing mozzarella whey to a (almost) boil denatures the albumin which precipitates out and can be strained to make ricotta.

When making yogurt the milk is heated to 190 or higher and then cooled. This is precisely to denature the albumin. The extra protein gives the yogurt a lot more structure.

However it means that there is no protein left in the whey- mostly lactose, lactic acid, and vitamin B.

  • That makes a ton of sense! I have successfully made yogurt by only bringing the temperature up to 120 degrees, not all the way to a high temperature and then lowering. In that case, I wonder if I could have different results. I'll have to take a look - thank you for the idea! I am going to play with this, I simply have too much whey on hand all the time to not try and do something more with it, you know?
    – Matthew
    Jan 27, 2012 at 18:41
  • @Matthew- If you do make yogurt, only bringing it to 120F, then your yogurt will be a bit more fragile- you can then make ricotta but you may need to add a little lemon juice to make the whey acidic enough- depending on how long you fermented your yogurt. Jan 27, 2012 at 18:45

The 1% milk is why it's not working for you. There's not enough fat in the whey to make cheese.

Aside from that, you should follow a recipe. The Home Cheesemaking book has a recipe for whey ricotta. Among other things, you don't simmer the whey; you only heat it to 180F.

  • Plenty of cheeses can be made successfully with skim milk. Mozzarella and ricotta are some of the easiest. They miss out on a lot of flavor of course. Jan 27, 2012 at 15:01
  • A number of recipes I've found call for the whey to be brought to 200 degrees, and that's the recipe my grandmother used as well. I brought it up to a simmer because nothing was precipitating out, and at that point I figured I didn't have anything to lose :)
    – Matthew
    Jan 27, 2012 at 18:42

I make ricotta out of yogurt whey all the time. I use some skim milk, usually add some half and half or heavy cream to make it more like whole milk. Add the whey (up to three cups), a dash of lemon juice and bring up to about 200 degrees. Let it sit undisturbed for about 15 minutes, covered, and drain the curds which will develop. You'll love the ricotta!

  • I suspect you're making cheese mostly out of skim milk and half-and-half, since that has so much more protein and fat than the whey.
    – Max
    Jan 9, 2020 at 19:44

You can make ricotta with yogurt whey you use it instead of the lemon juice. Add 1 quart whey to 1/2 gallon of 2percent milk bring to 180 and watch it curdle. Strain through fine sieve or cheesecloth.

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