
Whey is the natural by product of straining dairy. It’s what you get if you make cheese or Greek yogurt. So what can you do with leftover whey? Well, don’t just pour it down the drain! There’s loads of different ways to use up whey.
All About Leftover Whey
Whey is essentially water, lactose and whey proteins. The flavour and sourness varies depending on the type of cheese/yogurt you made.
- Sour whey comes from cheese made using citric acid or vinegar. It has a high acidity, high lactose and will not continue to ferment as it ages.
- Sweet whey is made from cultured dairy. It will taste sweet for the first 3 hours after draining. After that it will become more acidic as the lactose is consumed by the lactobacteria. Storing sweet whey in the fridge will help slow the acidification, but only for a short time. Sweet whey is probiotic and lower in lactose.
Here are some of my favourite ways to use up extra whey.
1. Hot chocolate
Fresh sweet whey from cheesemaking is actually very sweet. I like to drink it straight or turn it into something yummy like hot chocolate, chai tea latte or ovaltine. Fresh whey is really only sweet for the first few hours, so take a break from cleaning the kitchen and enjoy a hot beverage while your cheese finishes draining.
2. Culturing

Sweet whey is full of lactobacteria. It is perfect for fermenting all sorts of things. Most grains, legumes, nuts and vegetables can use sweet whey as a starter. This won’t work for acid whey because it doesn’t have the bacterial culture.
3. Soups and Stews

One of the best ways to use up leftover whey is as a base for soup. Replace the broth or water in a recipe with whey at a 1:1 ratio. It adds a richness and tanginess that really brings out the flavours of the other ingredients.
Here are a few recipes that were designed to use up leftover whey:
- Creamy whey and vegetable soup
- Traditional whey minestrone
- Indian paneer and whey soup
- Iranian whey and walnut soup
4. Baking

Leftover whey is perfect for any recipe that calls for buttermilk. It’s not as thick as buttermilk, but it certainly works to balance the acids in the batter.
Here are a few baked goods that are perfect for whey:
You can also use whey instead of water in any quick-rise yeasted bread recipe. It will add a delicious sourdough-like flavour to the bread.
5. Smoothies and popsicles
This is probably the easiest way to use up some extra whey! Turning your whey into smoothies or creamsicles.
6. Cheese Sauce
My kids love macaroni and cheese, and replacing the milk with whey results in a slightly tangier cheese sauce. It works for both packaged mac n’ cheese (affiliate link) and homemade cheese sauce.
7. Treats!

Whey can be used instead of water for all sorts of things from jello to berry sauce. Or check out my recipe for a lemon and whey meringue pie.
8. Whey Cheeses

There are a number of cheeses that can be made from fresh sweet whey. However, unless you are making enormous amounts of whey, you will never have enough to make gjetost. Alternatively whey ricotta can be made from only a few cups of sweet whey.
9. Uses around the house
If you’ve used whey for all sorts of edible things, and you still have tons of it sitting around, you could use it to:
- Water your acid loving plants (in particular, rhododendrons and blue berries)
- Presoak beans and grains to soften them before cooking
- Feed it to your dogs / pigs / chickens
- Whey bubble bath: Add a gallon of whey when you fill your tub and it will bubble up! The probiotics in sweet whey is great for your skin.

I have no access to sweet whey, but all the sour whey I could possibly want. Is there ANYTHING??? I can do with it? This whey, both cow and goat milk, is a byproduct of the fresh cheeses made in a local creamery. They all use starter bacteria, they all use rennet, but the whey is not considered sweet. Thanks in advance for any advice or help!
~Allen
I imagine that you’re getting it 24 hours or so after the cheesemaking process, which is why it is quite sour (it acidifies over time.) However, if they aren’t curdling it with acid, then it will still be good for most of these recipes. Try one of the soups adding just 1 cup of whey at a time to see how much you can use before it becomes too sour. It is also perfect for baking. The only thing you can’t do with cultured sour whey is make a sweet whey cheese.
Hi! How long will whey keep in the fridge?
Whey is only sweet if it is the first 3 hours after fermenting. However, acid whey from cultured cheese or yogurt should last 2 weeks in the fridge because of the bacterial culture. If you made cheese with acid (lemon juice, vinegar, citric acid) then I would use the whey within 1 week.
Will it remain sweet if I immediately freeze the whey from making Greek yogurt? That way I am collecting enough to use.
Unfortunately, whey from Greek yogurt is always an acid whey since the yogurt has already cultured for more than 3 hours (and acidified). So you won’t be able to use it to make ricotta. However, you can freeze it for smoothies, soups and other uses. Enjoy!
Per Wikipedia, Whey is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacture of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types of hard cheese, like cheddar or Swiss cheese. Acid whey (also known as sour whey) is a byproduct brought out during the making of acid types of dairy products, such as cottage cheese or strained yogurt.
You mentioned above that: Sweet whey is made from cultured dairy. This statement conflicts with what Wikipedia is saying. Can you please clarify. Thanks.
Hi, The difference between sweet whey and acid whey has been really hard to get across to readers. Mostly because a lot of people want to use their whey from Greek yogurt as sweet whey (when it isn’t.) 🙂
Hard cheeses are also cultured, but what makes the whey sweet is that it is only a few hours old (including the culturing time.) Even whey from hard cheese becomes acidic over time, as the bacterial culture continues to eat up sugars and acidify the whey. Thus sweet whey will turn into acidic whey within less than 24 hours. I think Wikipedia is just giving an easy overview of the topic. Cheers!
Can I use the whey from Greek Yogurt as a starter for sourdough bread?
Sorry… yogurt is just bacteria… sourdough bread needs a yeast-based culture. However you could use it for a quick soda bread: https://www.fermentingforfoodies.com/traditional-irish-soda-bread/
This what I have understood but I might be wrong. Cheese made with culture or without culture will have sweet whey as a byproduct if you curdle it with rennet. If you use some form of live culture it will in time convert to sour whey. If you only use live culture to curdle the milk you only produce sour whey. When using rennet the milk quickly curdles leaving insufficient time for the live culture to effect the balance of lactose in the why. Did I miss anything? Thanks
Yes, time is key to sweet versus sour whey. I get a lot of questions from people who make Greek yogurt and think that because they are using the whey right after draining that it is sweet. But whey from yogurt can never be sweet. 🙂
Hi
I got whey when I meant to make butter milk by taking about a half cup of my previous batch, and maybe left it too long. It separated. So I strained it like you would for cheese. I ended up with a ricotto/cream cheese type cheese. And noticed that after I had refrigerated the whey it had a slightly slimy consistency to it. Is this normal? and ok to consume?
Hum, slightly slimy is unusual. Sometimes cultured whey can be thick due to the bacteria (or yeast from milk kefir). Milk that has gone off usually smells bad. So if it doesn’t smell bad, then you could give it a little taste, and if it doesn’t taste bad, it’s probably fine. Most likely just thick from the bacterial culture in your buttermilk. Good luck!