Just like certain movies stay in theaters for months (we’re smiling as we look at you, Wicked) and others debut for a week then make their speedy departure, foods have a wide variety of lifespans. Some types of leftovers last for just 3 days before being past their prime, while these pantry staples are good for more than a year (including salt, which maintains its quality for 3+ years). 

As we were making our latest meal prep batch of overnight oats, we realized that we had been working our way through the same large container of grains for several months. Which got us wondering, “does oatmeal go bad?”

What Does the Expiration Date Mean on Oatmeal? 

Oats and most grains last much longer than the perishables you keep in the fridge, confirms Sarena Shasteen, culinary content specialist and marketing community engagement strategist at Bob’s Red Mill in Portland Oregon. But if you check on the package, you’ll almost always see that oatmeal does have an expiration date. 

“The expiration date is a general ‘best by’ date and, if stored properly, oatmeal can often last much longer than the date on the container,” says Sarah Brekke, M.S., Better Homes & Gardens Test Kitchen brand manager.

The date listed on your container of bag of oats indicates when quality might start to decline. Shasteen recommends aiming to polish off your package before this date if possible, however, there’s not an inherent safety risk in stretching this, the experts agree.

Does Oatmeal Go Bad?

But just because this is a “best by” date doesn’t mean that grains can’t spoil. Oatmeal can go bad. The three most common causes for spoilage: temperature fluctuations, moisture, and rancid oil.

“Even if your oatmeal is kept in a package, temperature changes can produce condensation, causing the contents inside to rot or mold. And if oats are exposed to moisture, they can develop mold. This can be seen as green or black spots, and it’s a clear sign that the oats are no longer safe to eat,” Shasteen tells BHG.

Rolled oats are steamed and toasted as part of their normal processing, which makes them more stable. Unprocessed oats, such as steel-cut, contain some oils that can go rancid over time—similar to other grains like whole-wheat flour our nut flours

In addition to declining quality after passing the “best by” date, there’s an increased risk for oats to be exposed to potential spoil-inducing elements like moisture or airborne yeasts that can lead to mold. Little bugs can also find their way in if the oats aren’t in a fully sealed vessel. This means it’s important to store your oats with care—and to use them as swiftly as you can. (We’re dishing up several awesome recipes with oats below to help make this goal easy to accomplish.)

How Long Do Oats Last?

There’s no need to sprint through your stock, though. When stored correctly, oats have a fairly long shelf life of about 1 year after opening. If left unopened for a fair amount of time, oats may last up to 2 years, Shasteen says.

How to Store Oatmeal to Max Out Its Fresh Shelf Life

That promise begs the question: How do you store oats to keep them fresh for as long as possible?

Keep oats in an airtight container with a tight lid in a cool, dark place, such as a dark cabinet or pantry. If your oats are sold in a bag with a resealable top, that works too. 

You can also transfer oats to a zip-top bag and freeze them for up to 1 year.

Speaking of the freezer, you can also freeze prepared oats. Shasteen walks us through exactly how to do so:

• Prepare your steel-cut, rolled oats, or instant oatmeal as desired, and allow it to cool to room temperature. 
• Scoop individual servings into the wells of a silicone muffin pan. 
• Freeze for 4 hours, or until the oatmeal is completely frozen. 
• Remove the oat cups from the pan, transfer to a zip-top freezer bag, and label with the name and date. Enjoy within 3 months.
• When you’re ready to enjoy, place the frozen oatmeal in a microwave-safe bowl with a splash of milk or water. Heat in 30-second intervals, stirring in between, until warm. Or warm in a saucepan over low heat, stirring occasionally, and adding liquid as needed.

How to Tell if Your Oats Are Past Their Prime

“The best way to tell if oats have gone bad is by using your senses,” Shasteen says.

If you notice any of these signs, discard your oats and get invest in a fresh batch, Brekke and Shasteen agree:

• Discoloration
• Green or black spots or other signs of mold
• Clumps
• Rancid, musty, or “off” odors
• Little bugs

The Best Oatmeal Recipes to Add to Your Menu

A cozy bowl of sweet or savory oats is never a bad idea. We also love tossing a handful of oats into smoothies to add heft, and frequently fold a small scoop into pancake batter to amp up the nutrition. (In case you missed it, oats offer gut-friendly and heart-healthy soluble fiber, a fair amount of protein, as well as energy-supporting iron and magnesium.) 

But these are far from the only ways to employ oats. To help you fly through your oats long before they have the chance to go bad, we’ve rounded up some of our greatest hits: