How To Tell When Different Milks Have Gone Bad

Visit the "dairy" section of your local grocer these days, and you'll discover a plethora of milk options, and we do mean plethora. There are lots of choices when it comes to shelf-stable milks too. Consumers have their pick between various strains of cow's milk, goat's milk, cashew milk, macadamia nut milk, almond milk, coconut milk, rice milk, or soy milk — just to name a few. While soy and rice milks have been around for a while, other plant based milks, like the ones from nuts, peas, and oats, have really grown in popularity the past decade. Of course, there are still some cow milk diehards out there, and some parents keep cow's milk around to feed growing children too.

No matter the type of milk, how do you know for certain if it's no longer drinkable? We've compiled a list of the surefire signs your milk (whether it's skim, whole, or hemp) needs to be poured down the drain.

Pea milk might have visible mold or unpleasant smell when it's no longer drinkable

Yes, before you read any further, trust us, pea milk is actually a thing, and yes, like dairy milk, it can get rancid. Ripple Foods sorta has the market cornered on pea milk, so we consider it the expert on the ol' ins and outs of pea protein-based products. The brains behind Ripple claim that pure pea protein (the kind that makes up the signature "Ripptein" that's in their plant based milks) is flavorless. By extension, you can expect it to smell pretty neutral. If you smell something a little funky or "off," you'll know that it's probably time to throw the milk away.

If you don't believe us or Ripple, Lively commenters in a Reddit thread agree, there shouldn't be an odor to pea milk and, while this should probably go without saying, there shouldn't be "obvious mold" on the surface. So if the pea milk isn't moldy or smelly, it's probably still good to go.

If almond milk is starting to clump, it's probably time to toss it

Almond milk has gotten really popular the last few years thanks to so many folks avoiding dairy. Prior to almond milk's popularity, soy milk was often a cow's milk alternative, but for people with soy allergies, that's not a great option either. But despite its ability to last longer than traditional cow's milk, it's important to note that almond milk isn't indestructible. How do you know when it's on its last leg? The clump factor is key. Carolyn Flood of NotMilk says (via Epicurious), "From a fresh product, it's very clear to tell when it's not good anymore. It definitely has a different smell and really starts to clump up."

Also something to keep in mind: Homemade almond milk (the kind you might whip up with a high-powered blender) will likely go bad sooner than the store-bought stuff since it lacks preservatives.

The actual carton of soy milk will start to show signs of spoilage

Soy milk has been a popular dairy alternative for many years. Just because it doesn't come from cows doesn't necessarily mean it can stay fresh for a super long time. Once opened, it usually only remains fresh in the refrigerator for a week, possibly up to 10 days. You can actually tell soy milk is going south by examining the actual milk carton. The carton will "bloat" or expand because the bacteria emanating from the milk is releasing gas. So if that carton feels a little bigger, definitely give it a sniff before pouring. It will be sour-smelling if it's no longer good, and if it's accidentally left out overnight outside of the fridge, definitely toss it.

Incidentally, the same goes for flax milk. If the container it's in looks puffier, the flax milk has likely gone bad and is no longer safe to drink. Don't take it from us, take it from the vegans at Vegans First who know their non-animal-based milks inside and out.

Skim milk will taste bitter when it's no longer fresh

The verdict is actually still out on whether skim milk spoils faster than whole or two percent milk. Can certain "fat-loving microbes" not form as swiftly in skim milk? Do whole milk's free fatty acids act as preservatives? There are lots of factors that affect the rate of spoilage for either type of milk, but experts do recommend always storing milk in the interior of the fridge as opposed to on the door where it's more often going to be exposed to warmer temperatures because of the constant opening and closing.

So while there is debate on the longevity of these different cow-based milks, one thing is for sure: Skim milk is gonna taste bitter if you take a slug and it's past its expiration date. Always trust your nose, of course, so if the smell is off, you know not to take a sip. If it smells fine but doesn't taste like the mildly sweet, run-of-the-mill skim milk you know it's supposed to taste like, give it the boot.

Rancid rice milk will not smell so sweet

Rice milk sales have been on the rise in the United States steadily since 1999. Since rice milk is essentially just water blended with milled rice, it breaks down from starchy carbs to sugar, and in turn, it has a sweeter taste to it than some of the other traditional dairy milk alternatives. Soy or almond milk, for example, are not as sweet-tasting as rice milk.

Before it's opened, shelf-stable rice milk's rate of spoilage can depend on how you store it. If the rice milk is exposed to a lot of light or heat, it can go bad faster, but in general, it can last about a month after the date on the package. Once opened, rice milk, according to active plant-based bloggers over at The Flaming Vegan, usually lasts seven to 10 days but will have an "off" odor if it's no longer fresh and safe to drink. 

Hemp milk gets chunky when it's rotten

Hemp milk is a popular plant-based cow's milk alternative because it's often described as both creamy and nutty. And contrary to popular belief, even though it's from the same plant that grows marijuana, you are not gonna get stoned by consuming hemp milk in any quantity. You will, however, get in some of your daily omega-3 fatty acids by drinking a daily dose of hemp milk.

Just the word "chunky" alone should make your second guess your milk's freshness status, but since hemp milk isn't exactly a common, everyday household item, we can see how this one might be harder to decipher. The plant milk enthusiasts blogging at The Flaming Vegan confirm that if your hemp milk is starting to chunk up, it is time to get rid of it. Like all milk, hemp milk should be smooth and completely liquified. If any part of it as formed a sizable solid, it's time to buy or make a fresh batch.

Whole milk sours once it's past its prime

Since it is like the OG milk (besides, you know, human breast milk), you'd think the average adult would know by now how to determine whether whole milk has lost its luster, but if the predictive text in the Google search bar is any indicator, people still need reassurance from the Internet on this one. 

How do you know for sure for sure if your whole milk is definitely no longer safe to consume? If whole milk — which might or might not spoil faster than its less fattening counterpart skim milk — has gone bad, it will both smell and taste very sour. Keeping milk stored in the back of the fridge (definitely not in the door, which is constantly exposed to warmer air) and making sure the lid is tightly sealed will help it stay preserved longer. The sniff test is never a bad idea if you've got a nose or two you can trust in the household.

If the texture of oat milk is more akin to yogurt than milk, it might not be safe to drink

Oat milk is really having a moment right now. It's gotten so popular the last couple years, there have actually been shortages. The oat milk connoisseurs at Oatly, a Swedish company that arguably put oat milk on the map, sell both shelf-stable and chilled oat milk. The people at Oatly claim it should stay fresh in your fridge for up to seven days after you initially open it. 

A little on the more cautious side, the plant lovers at Vegans First claim oat milk lasts four to seven days once opened. They suggest that you evaluate the consistency of the oat milk about four days after opening it and keeping it refrigerated. If the milk starts to seem more like yogurt than milk, well, it's probably not great milk anymore.

Coconut milk has a darker color when it's spoiled

Coconut milk has grown immensely in popularity the past few years. You can buy it from a can on the shelf or a box in the "dairy" section, and while it is higher in fat, it still has a number of health benefits too. 

Coconut milk longevity can depend on what form you buy it in. The canned milk can last a few years prior to opening. Once opened, whether from a can or a carton, coconut milk does have an expiration date. Canned coconut milk lasts for about a week after opening, while the carton coconut milk can stay fresh up to 10 days. Like a lot of milk-type beverages, coconut milk can start to curdle when it's bad. It might also appear to be darker in color, so if it appears to have changed in hue, take note: It could be ready for the trash.

If you can't easily pour the buttermilk, it's likely hit its expiration

Buttermilk is basically fermented milk, often used in cooking or baking. Buttermilk pancakes or biscuits, anyone? Like regular cow's milk (and all the other milks out there), it does have a shelf life. 

In general, it tends to last in your fridge for about two weeks. If you buy some to make pancakes, forget it's there, then have another recipe that calls for buttermilk on deck, how do you know if you need to go buy a new container? If it still smells okay but it's past the sell-by or expiration date, there is always the sniff test. But since buttermilk smells a little sour to begin with (it is fermented, after all), that can be hard to trust. That's why it's suggested that your try to pour a little. If it's somewhat difficult to pour, then it's probably time to toss it and replace it with a fresh carton.