10 Ways to Repurpose Sour Milk (2024)

There may be no use crying over spilled milk, but we can certainly get irritated when it sours! There are few things as frustrating as when food spoils. We all work really hard for our sustenance, especially if we’re tending and milking our own livestock. Fortunately, there’s no need to fret: there are plenty of ways to use sour milk so nothing goes to waste.

What is Sour Milk?

If you’ve ever smelled or tasted milk that has gone sour, you’ll remember the experience. Fresh milk has a clean, crisp, sweet flavor to it, especially when you drink it cold straight from the fridge. In contrast, sour milk tastes like you’ve mixed vinegar into it. This stuff smells like a gym sock and will coat your mouth in gag-worthy blech if you make the mistake of trying it.

The reason milk goes sour is that the lactobacillus bacteria inside it has “bloomed.” Basically, this means that it has reproduced rather enthusiastically. Normally these bacteria are kept in check with either pasteurization or refrigeration. If your fresh milk was left on the counter too long, especially in warmer weather, the higher temperatures made the bacteria go all “ooh la la.”

This strand of bacteria feeds on the lactose in dairy for energy, which it uses up when it breeds. The by-product from its activity is lactic acid, which gives sour milk its tart (sour) flavor. This is the same lactic acid created by cabbage when it ferments into sauerkraut or kimchi.

If the lactic acid is allowed to flourish, it turns the milk protein casein into curds. Hence “curdled” milk. And what are curds? Cheese!

Sour milk by itself is not appetizing, but they are generally safe to use. Below are some of the key things you can do with your sour milk, other than pouring it down the sink.

1. Bake with It!

Many recipes, particularly bread, various pancakes, and waffles, specifically call for “soured milk” or sometimes buttermilk. This generally involves adding a spoonful of lemon juice or vinegar to ferment the milk a little bit. Apparently, this creates a type of fermentation that helps to leaven the other ingredients and increases shelf life. Isn’t that cool?

If you wake up to a container of sour milk, consider a surprise pancake or waffle meal. Not only will you put all that dairy goodness to excellent use, few family members will complain about a stack of waffles for breakfast.
Or dinner.

You can also use that sour milk to create sourdough bread and biscuits.

2. Make Some Cheese

Cheese is basically milk that’s gone “off.” As a result, using sour milk to make cheese accelerates the process a little bit. Cottage cheese, ricotta, and cream cheese are the easiest to make, though you can make a variety of different kinds, depending on which ingredients you have on hand.

If you haven’t tried homemade cheesemaking yet, consider this a perfect opportunity to try doing so. It’s a lot easier than you think, and you already have one of the key ingredients. A basic cottage cheese is probably the easiest, and the most versatile. You can eat it as is, use it in lasagna, or compress it into paneer.

3. Add it to Sauce, Soup, Casseroles, etc.

If you like creamy savory dishes, use that soured milk in some of your favorite recipes. For example, scalloped potatoes get an extra kick from it, and sour milk also works well in recipes like clam chowder, broccoli soup, and various casseroles.

The best way to use this kind of milk to thicken dishes like these is in a roux. Mix equal parts butter and flour together in a small saucepan on medium heat, whisking regularly to make a paste. Then lower the heat and add the sour milk in bit by bit, whisking the entire time. You should end up with a sort of thick cream.

Use a spatula to add this to soup, or to mix directly into your pasta or casserole.

4. Make Salad Dressing

Do you enjoy creamy, slightly tangy salad dressings like Caesar or Ranch? Guess what’s perfect as a base for these beauties? Pulse the sour milk with a bit of sour cream or yogurt, a spoonful of mayonnaise, and seasonings such as fresh parsley, chives, dill, salt, pepper, and garlic powder in a blender.

Adjust the ratios depending on whether you’re aiming for a thinner dressing, or a thick dipping sauce. Season to taste, and enjoy!

5. Use Sour Milk to Marinate Chicken

Have you ever eaten chicken that was marinated in buttermilk? It’s astonishingly tender and juicy. This is because the milk acids in buttermilk tenderize the flesh, and allow it to retain moisture more easily. The acidity in sour milk creates the same effect.

To use it in for chicken, prep the meat in a bowl and pour the sour milk over it. Make sure to coat it well, then cover the bowl and refrigerate it for a good 12 hours, at least.

6. Soak Grains in It

Some holistic nutritionists advise that people soak grains in cultured or fermented dairy. This helps to break down the fibrous coatings on those grains, which are full of inflammatory “anti-nutrients.” These include lectins (which are harmful to people with autoimmune conditions), enzyme inhibitors, and phytic acid.

By soaking grains in sour milk or kefir, the grains are a bit pre-digested. This makes it far easier for the human body to break them down and absorb their beneficial nutrients.

If you’d like to try this out, soak your grains for at least eight hours before cooking them or using them to bake with. This allows the phytic acid time to break down.

7. Polish Your Silverware

Do you have silver items that have gotten tarnished? Good news! The same mild acid that will tenderize your chicken will clean the tarnish off real silverware. Just put the items in a shallow pan and cover everything with the sour milk. Cover it with some plastic wrap, and let it sit on the counter for about an hour.

Then wash it in soapy water, rinse it, and rub it dry with a clean cloth. It should be wonderfully shiny and sparkly! Just make sure to toss out the milk it soaked in so nobody gets ill.

8. Add it to Your Next Bath

Have you ever taken a milk bath before? It can help soften and smooth your skin, and may also offer some anti-inflammatory benefits. For example, milk baths can alleviate the discomfort and itching associated with chicken pox, poison ivy, and sunburns.

Just pour the milk into your next bath, and soak in it for a good 15 minutes for maximum benefit. Just avoid using sugar scrubs in combination with the milk, as you may end up with less-than-comfortable skin (or internal) conditions.

9. Give Your Livestock a Treat

Pigs and hens can both benefit from a bit of sour milk added to their feed now and then. Since dairy is so high in protein and calcium, it’ll act like a supplement for your chickens. Sour milk is particularly high in riboflavin—as is yogurt—which results in better egg development. It’ll also plump the hens up a bit more, which is great if you’re raising meat birds.

10. Feed Your Plants

Many plants really benefit from milk and other dairy products. As an example, I had a lot of trouble with my pumpkins a couple of years ago, as they suffered terribly from blossom end rot. This is caused by calcium deficiencies during the flowering period. As a result, fed them watered-down milk the next time I grew them. This resulted in very healthy, happy pumpkins (and a lot of pie and soup for my family).

Water down the sour milk at a 1:2 ratio of milk to water. Then offer this drink to your fruiting plants at the soil level. Your Cucurbitaceae plants (such as pumpkins, squashes, melons, and cukes) will appreciate the extra nutrients, as will various Solanaceace (nightshade) species like tomatoes and eggplants.

Remember: Sour Milk is Not the Same as Curdled Milk

As a final note, when we talk about sour milk here, we’re just talking about milk that has a slightly sour taste, but is still otherwise okay. If it has a greenish hue and is curdled and clumpy, it’s really not good to use anymore. Not even as animal feed.

If your milk has gone so bad that it makes you gag just to look at it, just add it to your compost pile. You might wince at the idea that this seems wasteful, but it’ll add its nutrients to the soil being created there.