How Long Can Soy Milk Sit Out? [Plus Great Health Benefits of Soy Milk]

Some people prefer drinking soy milk to traditional cow’s milk for many reasons.

You may have walked through the grocery store and noticed that some soy milk is kept in the refrigerated section, while other cartons are kept out on the shelf sitting out at room temperature. Now you’re wondering, “How long can soy milk sit out?”

Soy milk, like other dairy alternatives, should not be left out at room temperature for extended periods. Generally, it’s safe for up to 2 hours; beyond this, bacterial growth increases, especially in temperatures above 40°F. In warmer conditions, over 90°F, the safe period decreases to just one hour. To maintain its freshness and prevent spoilage, soy milk should be refrigerated and consumed within 7-10 days of opening.

What Is UHT Processing?

Because of UHT processing, consumers can purchase shelf-stable dairy milk, almond milk, coconut milk, and other milk alternatives kept at room temperature.

The experts heat the milk to 135˚C, which is 275 degrees Fahrenheit. The milk only stays at this temperature for a few seconds.

Then they cool it quickly and put it into sterile cartons made of six layers of paperboard.

It’s a fascinating process, but the specifics aren’t necessary. Now when you want to go on that camping trip, and the cooler space is limited, you can keep shelf-stable milk in a cool dark place and cool it off when you’re ready for a drink. 

How Long Can Soy Milk Sit Out At Room Temperature?

The Danger Zone we mentioned earlier, which the USDA sets, refers to letting soy milk opened or previously refrigerated.

If you opened a single container and left it sitting on the breakfast table for longer than 2-hours, you should throw it away. 

Unopened shelf-stable soy milk can sit out for 3 to 4 weeks from the date on the carton.

That stamp is not an expiration date, but a date added to the carton after the UHT processing, so the consumer will know when it begins to go bad.  

Once you open that container, you have to put it in the fridge. Otherwise, you risk it moving into that 2-hour time zone that will bring it to dangerous temperatures.

How Long Can A Glass Of Soy Milk Sit Out?

A glass of soy milk is the same as an opened carton. It’s out at room temperature and not sealed in a safe container, so 2-hours should be a limited time.

You should drink it within that window to avoid any dangerous foodborne illnesses. If you can’t finish your glass and the 2-hour window approaches, put it back in the fridge. 

If you are doing homework and see that your glass of soy milk has been sitting out well past the 2-hour window, dump it down the drain and pour yourself another glass.

Before you let the second glass sit out, be sure you will drink it in that 2-hours. Otherwise, pour yourself a glass of water while you study or work, and save the soy milk for when you can drink it. 

How Long Can Soy Milk Sit Out Before It Goes Bad?

Once your soy milk starts to hit that 2-hour time limit set by the USDA, it begins to go bad. So 2-hours is how long soy milk can sit out before going bad.

It may not smell bad or look spoiled, but that doesn’t mean bacteria hasn’t already started to multiply. Some pathogens that cause food poisoning are not detectible by sight or smell. 

The 2-hour rule only applies to soy milk that has been opened or previously refrigerated.


Unopened shelf-stable soy milk can be kept out at room temperature for 3 to 4 weeks after the date on the container. If it moves past that point, you should get rid of it. 

When in doubt, throw it out. Otherwise, you can get sick, and food poisoning is nothing to joke about.

Some bacteria will leave you sick for the day, while others might leave you laid up for weeks or in the hospital.

While wasting food is a shame, your health is far more critical when it comes to leaving food out at room temperature. 

Can Soy Milk Sit Out Overnight?

The only soy milk that can sit out overnight is the brands sold stored at room temperature.

There is a little seal at the opening of those cartons designed to keep fresh soy milk from going bad. Once you’ve broken that seal, you cannot leave the container out for longer than two hours. 

If you’ve purchased the brand of soy milk stored in the refrigerated section of the grocery store, you cannot leave it out overnight and should get it back into the fridge by that 2-hour recommended window. 

Does Soy Milk Go Bad At Room Temperature?

It depends on the container and if the seal has been cracked. Soy milk packaged in shelf-safe cartons will go rancid at room temperature, but only if it’s past four weeks from the container’s date. 

Soy Milk

No matter the container, soy milk that has been opened will start to go wrong if left at room temperature in 2-hours.

This is when your soy milk will enter the Danger Zone, which is between 40˚F and 140˚F.

Is Soy Milk OK If Left Out Overnight?

This also depends on the packaging and whether or not that soy milk has been opened.

Shelf-stable cartons are designed to keep all milk products, including soy milk, safe to drink even if they are left out at room temp.

The refrigerated variety has a shorter shelf-life when compared with the shelf-stable options. 

Soy milk of the refrigerated variety will last one week from the expiry date on the unopened carton.

Once opened, you have about a week (7 days) to drink it or risk bacterial growth that can cause foodborne illnesses. Some bacteria multiply in temperatures lower than 40˚F. 

Old soy milk can make someone sick with symptoms like abdominal pain and dehydration. Use common sense when it comes to what you put into your body. If it’s old, get rid of it. 

Sometimes food can go bad before the date on the carton indicates, so once that date has passed, you should give it a sight and smell test.

If the white color has turned or it gives off an odd odor, throw it away. The date is always a good indicator of its shelf-life, but it never hurts to be safe.  

How Long Can A Soy Latte Sit Out?

The longest you want to let your soy latte sit out is 2-hours. Just because the soy milk goes through temperature changes, bacterial growth is always a risk once your food or drink has sat out past that 2-hour limit.

Bad soy milk will likely lay you up for a week with a myriad of symptoms that resemble the flu. 

Soy Milk

If your soy latte has been sitting out for an extended period that reaches over that 2-hour recommendation, throw it away and order another.

Non-dairy milk is just as likely to host harmful bacterial as other dairy products.

Why Does Some Soy Milk Need To Be Refrigerated?

Soy milk kept shelf-stable can sit out at room temperature for longer than 2 hours because it’s stored in a soy milk container after going through UHT processing, which we explain above.

When subjected to these types of heat sources, it sustains their food quality and life. 

Can I Make My Soy Milk? 

Yes. And it’s much simpler than you might think. All you do is take some soybeans and soak them in water overnight.

Drain them in the morning and blend them with water until smooth. Use a cheesecloth to strain the milk from the pulp.

Put the milk into a pan and add water. When it comes to a boil, stir it and make sure to skim the foam from the top. 

Let it cook for twenty minutes and then cool. If you like, you can add a vanilla bean while cooking to add flavor. The best place to store homemade soy milk is in the refrigerator for 3-5 days in a sealed container.

There are likely different ways to make soy milk at home, but this seems to be a standard way that’s simple in any kitchen. 

When you make food at home, you know it’s good quality, essential for our health as the printed date on soy milk containers.

Speaking of, make sure to date your creation, so you remember when you placed it in the fridge. You can create different types of soy milk like chocolate or almond if you prefer a variety. 

Is Soy Milk Good For You?

According to the Cleveland Clinic, soy is a “lean plant protein” that would be a great addition to someone’s diet, including soy milk.

The latest dietary guidelines for Americans recommends incorporating soy products into your diet. 

Doctors once warned breast cancer survivors that soy milk is risky, but it seems that was old news. According to the Mayo Clinic, a “moderate amount of soy foods” won’t increase a person’s chances of getting breast cancer. 

If you’re a cancer survivor of any kind, we recommend speaking to your oncologist before making any significant dietary changes in your life. 

Here are some of the benefits of drinking soy milk. 

  • There is a lower risk for dementia and Alzheimer’s disease due to the Omega-3 fatty acids. 
  • It is full of potassium, which can lower blood pressure and cholesterol levels. 
  • It’s fortified with added nutrients. 
  • Soy milk has isoflavones that help reduce the symptoms of menopause. (Isoflavones could also affect menopausal women negatively and reduce thyroid function. One must have enough iodine in their system to avoid this. We suggest consulting your doctor if you’re menopausal and considering soy milk.)
  • It is a fantastic source of vitamins, A and B and has ample calcium retinol, folate, and choline supplies. 

What If I’m Allergic To Soy?

By all means, if you are allergic to soy, do not drink soy milk. You can choose almond or coconut milk as other great alternatives.

Final Verdict

The biggest lesson we’ve learned from this article is that the way they store soy milk at the grocery store is an excellent indicator of how you should store it at home.

Some cartons of soy milk are in the cooler section, while others are kept on store shelves.

We’ve also learned that it’s a bad idea to drink opened soy milk that has been left out at room temperature for a long period, more than 2-hours to be precise. 

Pay attention to the dates printed on the carton and always err on the side of caution. Your stomach and the guts of those you love will thank you for the extra effort. 

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