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Is Watery Yogurt Bad for You?


You bought yogurt from the grocery store, opened the container, and surprise, surprise… there’s this watery substance floating on top. You have no idea what it where and where it came from, but it’s already making you ask, “Is this yogurt really safe for me to eat?”

Fear not; watery yogurt is not that unusual. Here’s why it’s completely safe for you to eat — and why that watery substance got there in the first place.

If you see a watery substance on top of yogurt when you open the carton, there’s no reason to worry. The yogurt hasn’t gone bad. The liquids have simply separated themselves from the solids. Just mix it in with the spoon and give the yogurt a good stir. Or pour it out, then eat the yogurt as you’d normally do.

Watery yogurt is safe to eat. But why is there water on top of yogurt in the first place? That watery substance isn’t really water — and can actually be very nutritional. It’s whey, a natural protein found in dairy products. Whey will separate from the curds in yogurt over time, forming a runny and cloudy liquid that floats on top.

This is a completely natural process and happens to most yogurts, both store-bought and homemade. While every now and then I like to make my own yogurt or kefir at home, most of the time I eat Chobani Plain Greek Yogurt and Activia Creamy Plain Yogurt (they taste good and I can find them in pretty much all of the stores I shop at). And I’ve had this happen to all of them, no matter when the “best by” date was or how I stored them.

As I was writing this post, I opened and ate a container of watery yogurt

Read the ingredients on yogurt cartons in the grocery store, and you’ll see that some companies add pectin and other additives to their product. These additives stabilize the yogurt, which stops whey from separating from the curd. Honestly? I prefer my yogurt runny, but natural, over thick, but with additives, on any day.

How Yogurt Is Made

Yogurt is a fermented milk product. It can generally be made from the milk of any domestic animal. In America, yogurt is made mostly from cow’s milk. Milk from goats, water buffalo, yaks, and camels is also used to make yogurt around the world.

Yogurt is made by adding streptococcus thermophilus and lactobacillus bulgaricus bacteria to raw milk and allowing it to ferment. When added to milk and heated, these bacteria turn the sugars (lactose) in the milk into lactic acid. The lactic acid thickens the milk and gives it its tangy taste. Longer fermentation results in thicker and tangier yogurt.

Make Plain Yogurt at Home

I remember how my great grandmother used to make milk. She’d heat fresh milk and she’d keep stirring it, so that it wouldn’t boil over. Then, she’d let it rest at room temperature. Once the milk cooled down, she’d scoop out a cup and mix it with yogurt to make yogurt starter (also called thinned yogurt).

My great grandma would then whisk the starter with the milk, cover it with a wet towel, and let it rest overnight. The next day, it had turned into very thick and super tangy yogurt. She’d strain the whey, pour it into jars, and store it in the fridge.

You can do the same thing at home. Just go out, buy whole milk and plain yogurt from the store, and follow the recipe. As you make more and more batches of home yogurt, you can use your own previous batches as the starters.

The yogurt that you and I buy from the store are made in a process that’s not that different. It’s just done in the highly-controlled environment of a factory and at a scale that’s virtually impossible to replicate at home.

Where Yogurt Comes From

Humanity has been producing and eating yogurt for thousands of years.

Yogurt is thought to have been invented in Mesopotamia in 5,000 BC. Ancient Indian writings also speak about yogurt with honey as “the food of the gods.” Yogurt was also prevalent in the diets of ancient Greeks.

Until the 1900s, yogurt was a staple in the Russian Empire, especially Central Asia and Caucasus. Over time, it spread to Eastern Europe and today, it’s very popular in Turkey, Greence, and in the Balkans.

Why It’s Called Greek Yogurt

Santorini, Greece
The beautiful island of Santorini in Greece

Greeks didn’t invent yogurt, but Greek Americans made yogurt popular in the United States. This is why plain strained yogurt is known and marketed as Greek yogurt.

In 1964, two brothers started the first commercially branded yogurt in Greece called FAGE (or ФАГЕ in Greek). It had a tangy taste and was drained of most of its water content. This meant that Greeks didn’t have to drain the yogurt themselves to make tzatziki.

In 1998, Costas Mastoras, the owner of a grocery store for Greek Americans in the Astoria neighbourhood in New York, visited FAGE in Greece to buy feta cheese. He tried a sample of strained yogurt and loved its thickness. He ordered 120 six-ounce containers and had them flown to the US.

Story goes that the yogurt sold out so quickly, Mastoras decided to establish FAGE USA and sell it to grocery stores across the US. Clearly, he did a good job.

Yogurt vs. Greek (Strained) Yogurt

Essentially, Greek yogurt is strained yogurt. Greek yogurt is thicker than regular yogurt because the whey is strained from it. Manufacturers do this so that consumers who buy Greek yogurt can make tzatziki, a creamy sauce made with strained yogurt, cucumber, and garlic. It also has less sugars and more protein compared to regular yogurt.

I can write about the differences all I what, but the facts speak best for themselves. So I bought one 5.3-oz container of no-fat Greek yogurt and one 5.3-oz container of no-fat regular yogurt from the grocery store. When I read the labels, here’s what I found.

Greek YogurtRegular Yogurt
80 calories90 calories
0 grams total fat0 grams total fat
5 milligrams cholesterol5 milligrams cholesterol
15 grams protein9 grams protein
6 grams carbohydrates12 grams carbohydrates
Comparing the nutritional facts of Greek yogurt to regular yogurt

Where Is Yogurt Available?

You can find yogurt in the dairy and eggs department of most stores, including Walmart, Kroger, and Costco. Yogurt is also available next to milk and egg cartons on the fridge isles of most neighborhood grocery stores in large cities.

If you prefer to shop online, you can get store-bought yogurt delivered to you with Instacart or buy some on Amazon. As a whole, it shouldn’t be too difficult to find yogurt. Finding good yogurt is another story.

Always read the ingredients on the label before you buy. Good yogurt contains only cow’s milk and bacteria cultures (S. Thermophilus, L. Bulgaricus, L. Acidophilus, Bifidus and/or L. Casei); it shouldn’t have any pectin, artificial flavorings, or preservatives.

Can Yogurt Be Frozen?

If you stocked up on yogurt on a special sale, you can freeze it, so that it won’t go bad for a longer period of time than when kept in the fridge. Just store the yogurt containers straight in the freezer or, if you bought a single large one, scoop out the yogurt and transfer it to several mason jars.

To freeze yogurt, store it in a container in the freezer for at least 2 hours. Frozen yogurt will last up to 3 months. To thaw the yogurt, transfer it to the fridge and let it sit there overnight.

The caveat to freezing yogurt is that it gets grainy and watery once thawed. Not all folks like this taste and texture, so try it out with one container and decide for yourself.

Does Yogurt Go Bad?

Open yogurt spoils sooner than unopened yogurt. My two cents are to eat a container of yogurt as soon as you open it and freeze any leftovers for later use. Unopened yogurt generally lasts longer than its expiry date. As long as it doesn’t smell strange, you can eat yogurt 1-2 weeks past its expiry date.

Keep in mind that the yogurt will have probably turned runny and water, as the liquids will have separated from the by that time. Mix them in with a spoon and eat the yogurt as usual or just tilt the container in the kitchen sink to drain them out.

Still, always try to eat your food before the “Best By” and certainly before the “Expiry” date. Freezing food before these dates until you can actually use it is a great way to eliminate waste.

In Conclusion

Yes, watery yogurt is safe to eat. That substance you see on top of yogurt when you sometimes open a container is whey, a natural protein found in milk. Over time, whey will separate from the yogurt curds and form a runny and cloudy substance in the container.

There’s two ways you can go from here. Some people stir it in and eat their yogurt as they’d normally do. Others want to keep the thick and creamy texture of yogurt, so they drain the watery substance from it before eating. This is totally up to your taste and liking.


Jim is the former editor of Home Cook World. He is a career food writer who's been cooking and baking at home ever since he could see over the counter and put a chair by the stove.

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