Yes, raw milk naturally sours! Here's why and what you need to know.

Raw milk. Such a simple old fashioned food. But, as a society over the past few generations, we've lost so much common sense knowledge about it. One big example is ---

Raw milk sours! It's a natural thing and impossible to stop in the fridge. 

This blog post will dive into all things sour... as it relates to raw milk. Keep reading to learn more.

Why Raw Milk Sours

The short answer is --- it's fermenting and turning into cheese! The living microbiology in raw milk is digesting the lactose (milk sugar) and making lactic acid. This is what makes raw milk naturally get more and more sour over time.

When I say "living microbiology", I'm specifically talking about lactic acid bacteria. Those are the ones that eat lactose. There are many kinds in raw milk, including Lactobacillus, Streptococcus thermophilus, Enterococcus, and Lactococcus. 

These lactic acid bacteria are probiotic! This is why raw milk is known for improving gut health. It's like a completely natural probiotic pill.

It's important to note that raw milk has all of the living microbiology intact. That includes microorganisms that aren't in the cow but around the cow. Yeasts and fungal spores come from the air. And potentially harmful bacteria can come from manure. This is why we keep our barn, cows, and equipment meticulously clean!

These outside-of-the-cow microorganisms do NOT eat lactose. So the fact that the milk sours does NOT indicate danger. It's a palatability issue, not a safety issue.

Instead, souring milk simply becomes more and more probiotic. The more sour the milk, the higher the amounts of lactic acid bacteria. The busier those bacteria were fermenting, eating the lactose, and creating lactic acid, the more their colonies grew.

What Affects The Souring Process

How fast raw milk sours depends on (1) how clean the milking process was (after all, lactic acid bacteria can grow on equipment); (2) how fast the milk was cooled down; and (3) how it's stored.

The first two are 100% our responsibility. The third point we share. It's our job to keep your milk cold until you get it. Then it's your responsibility to properly store it at home.

Once you get your raw milk, how fast it sours depends on temp and time. The higher the temp, the faster the fermentation. The longer it sits, the more it ferments. 

Storage Tips

COUNTER: If you want to purposefully sour your milk, the counter is the way to go. When fresh raw milk is kept on the counter, it will start to sour overnight and will become unpalatable within a few days.

If you want your raw milk to sour very quickly, then leave it at a higher temp. Remember that all the wonderful properties of raw begin to break down when heated above 110F... and that includes the lactic acid bacteria! So never store raw milk you want to sour over 110F.

FRIDGE: When kept in the fridge, raw milk typically starts to develop a sour flavor in 7-14 days. It will likely become too sour to palate in about 10-21 days. 

There's no way to stop the fermentation, but there is a way to optimize it.

The ideal storage temp for raw milk is 33-38F. The average fridge is usually 35-40F, so using a thermometer will help you figure out if your fridge is the perfect temp. Also keep in mind that different parts of your fridge may be different temps. The lowest, farthest back part of your fridge is usually the coldest and therefore likely the best spot for your milk.

FREEZER: Yes, you can freeze raw milk for up to 6 months! Once thawed, it may become clumpy. Simply shake to recombine. 

Freezing raw milk pauses fermentation. The living microbiology will (mostly) come back to life when thawed, and then your milk will continue to ferment and get sour. 

Keep in mind that the longer raw milk is frozen, the more probiotic loss. Because of this, I don't recommend freezing for more than 6 months.

*An important note it that some people can detect a undesirable flavor difference in previously frozen milk. So, if you haven't done it before, I recommend freezing a small amount first. Test it and see how you like it. You definitely don't want to waste any milk!

How To Use Sour Milk

Whether for your human or furry family, sour milk is 100% fine to consume. It's not a safety issue but a palatability issue. 

CHOCOLATE MILK: This is a way to mask the sourness. Heat 1 cup water, 1 cup cocoa powder, and 1/2 tsp sea salt in a pot on the stove. Once smooth, stir in 1 cup maple syrup. Now you have chocolate syrup to flavor your sour milk with! I usually use about 1 cup of chocolate syrup to a gallon of milk.

RICOTTA CHEESE: This is my favorite way to use up sour milk. Heat 1/2 gallon of sour milk and 1/2 tsp of sea salt in a pot on the stove until steaming (around 185F). Lower the heat and add 3 Tbsp of lemon juice (or vinegar). Stir for about 2 minutes. You'll notice the curds separating from the whey. Turn the heat off and let it sit for 20 minutes. Then, pour into a cheesecloth-lined colander set inside a large bowl. For a creamier cheese, let sit 3-5 minutes. For a firmer cheese, let sit up to 20 minutes. Enjoy immediately or store in the fridge for up to 3 days.

COOKING AND BAKING: Guess what? For any recipe that calls for buttermilk, you can sub with sour milk! Think sour milk pancakes, marinating chicken, or homemade ranch dressing.

Have You Tried Triple E's Raw Milk?

How long does yours last? How do you store it? What do you do with sour milk?