Do overnight oats go bad

In this brief guide, we will address the query, “do overnight oats go bad?” We will also discuss what is the shelf life of overnight oats and how you need to store them.

Do overnight oats go bad?

Yes, overnight oats go bad. The longest time that overnight oats have lasted is for up to 5 days, so it makes sense that this dish is used for meal prep. 

You can also choose a storage method that allows you to enjoy overnight oats taste for a longer period.

It also depends on what ingredients you use to enrich your overnight oats, you can choose from milk, yogurt, or the fruit of your choice. All of these goods should be consumed within a few days, or they will expire.

If you want to know more about overnight oats and what makes them a good option for breakfast, just keep reading! 

What are overnight oats and how can they be prepared?

Overnight oats are the favorite breakfast for many people who are always in a hurry as they only take 5 minutes to be prepared. Also, they can be served with yogurt, milk, or fruit so you can create interesting food combinations.

The good thing about overnight oats is that they do not involve any cooking. All you need to do is to mix the ingredients and leave them to marinate overnight. That is the reason for their name.

You can also add some other seeds, like chia or flaxseed to make it a healthier option. In just one meal you will obtain protein, fat, carbohydrates, fiber, and an amazing taste that will only take you 5 minutes!

What do you need to prepare overnight oats?

Overnight oats are easy to prepare and will take zero time, also, you do not need that many ingredients. If you are looking for a more complex taste, you can add some other options of proteins, seeds, fruits, or sweeteners.

The most common ingredients to prepare overnight oats are

  • Oats (of course!). You can use rolled or instant oats to prepare this breakfast, they will provide the best texture to the meal.
  • Milk. You can also use water to prepare overnight oats, but milk is more popular and adds a richer texture. In recent years, plant-based milk is the favorite to prepare this meal.
  • Chia or flax seeds. To provide you with more nutrients, you can add some other seeds. Chia seeds will give the pudding texture that many people love.
  • Greek yogurt. This can work as an additional source of protein, and can add a creamy flavor that will drive you crazy!
  • Vanilla extract. Just a few drops of this ingredient will help you boost all of the flavors that compound overnight oats.
  • Sweetener. You can choose to sweeten your oats or leave them plain. To do so, you can use honey or maple syrup, trust me, this will change your whole oats experience!
  • Extras. The good thing about overnight oats is that you can add your favorite ingredients, like fruits, nuts, seeds, cereals, and spices. It’s up to you!

To prepare them, you first need to place oats and chia seeds in the glass. Then, you need to add the milk and sweetener of your choice. Mix until everything is incorporated and cover it. All you need to do now is to leave it in the store overnight and you are good to go!

How long do overnight oats last?

Overnight oats can last for up to 5 days when stored in the fridge, this is what makes it an excellent option for meal prep. You can also choose the freezer to preserve your oats for a longer period.

The only thing you need to avoid is to store overnight oats at room temperature as this can cause quick spoilage. 

Can you leave overnight oats unrefrigerated?

Overnight oats are prepared with different perishable ingredients, which is why it is not recommended to leave them unrefrigerated. When unrefrigerated, microorganisms will reproduce quickly which can lead to rapid spoilage.

So, all you need to do is to guarantee overnight oats are not unrefrigerated for longer than 4 hours, besides the texture will not be the same as fresh.

How can you tell when overnight oats have gone bad?

If you prepare your overnight oats at the beginning of the week, you must check them constantly for any sign of spoilage. You can know when spoilage has occurred thanks to these signs

  • Pungent smell.
  • Mold growth.
  • Color changes.
  • Funky taste.

Make sure you check your oats before consuming them, this will save you from foodborne illness and a horrific flavor! You can get further guidance on this subject in this link.


In this brief guide, we have addressed the query, “do overnight oats go bad?” We have also discussed other queries related to the subject at hand. 

Hope you found this blog useful. If you have any questions, please let us know.


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.