Why Are My Overnight Oats Slimy? (Get The Ratios Right)

I recently made overnight oats for the first time (yes, late to the party) – but found the cold, slimy texture off-putting. The result didn’t live up to the hype. Seeing how popular the breakfast dish has become, I looked to improve my overnight oats as surely this wasn’t all it.

After a bit of side-by-side testing, I managed to improve the texture and this is what I found out:

It’s normal for overnight oats to become slightly slimy due to the starches in the oats releasing in liquid over time. You can avoid an overly slimy texture by using a ratio of 1:1 milk and oats to make it thicker. Adding other toppings like fruit and nuts also benefits the texture.

I think the key for me was to make the oats thick enough so they didn’t “drip” off the spoon. Too much milk mixes with starches from the oats to make a gluey slime, and this was the texture that I didn’t like. When it is more solid, the oats mix in more and that texture becomes unnoticeable.

How I Overcame Slimy Overnight Oats

After my first bad attempt, I decided to try some different tests out to find a texture that I liked. Admittedly, I don’t think I really followed a recipe the first time, and just added some milk and oats, eyeballing the quantities. That clearly wasn’t the way to go as the ratios are quite important.

So here were some different recipes I tried in some food storage containers. The ratios were by volume, so 1 cup of milk for 1 cup of oats.

Milk And Oats 1:1 Ratio.

This was a classic ratio I found online which was said to make thicker, spoonable overnight oats. I thought the slimy texture from last time might have been made worst from being too watery. The result: this was much better as expected. It resembled a porridge that was thicker and heartier. The slimy texture was hardly noticeable and seemed to taste better too.

Milk And Oats 2:1 Ratio.

I wanted to add this recipe in so I could test against the 1:1 ratio and see which I preferred. I was guessing that I preferred thicker overnight oats, but couldn’t be sure, so wanted to make a thinner one to compare. The result: I couldn’t stand this – the texture like slimy glue or snot. The milk with the starch obviously makes a paste-like texture that I don’t get along with.

Yogurt, Milk, And Oats 1:1:1 Ratio.

I had seen this in a few recipes and it looked like a good idea. The yogurt might disrupt the texture and make it more creamy. It certainly looked a lot different after mixing – much creamier, and whiter. The result: this was an OK texture, but the yogurt was a bit overpowering. The tartness of the yogurt took center stage, so perhaps needed less. Yogurt as a topping might be better.

Rinsing Oats First And Then A 1:1 Ratio.

I hadn’t seen this anywhere online, but I thought about how some rice gets too gooey unless you rinse it first. This is because of the starch on the outside that thickens up as it cooks. It looked pretty weird when I rinsed it in a sieve. The result: this was the worse. Obvious to see why no one does it. The oats lost their creaminess but still went slimy. I would say they had the worse texture of them all.


The 1:1 ratio was very nice, and I enjoyed the oats both by themself and topped with some apple and pecans. I’ll be using this again and I’m glad I found a recipe that worked. If you don’t like overnight oats then give this a try – 1 cup of milk with 1 cup of oats and a pinch of salt.

Since writing this article I’ve tried other types of milk in my overnight oats and wrote about the 9 best milk to use for overnight oats here.

If You Still Don’t Like The Texture Of Soaked Oats…

While researching this post, I found a Reddit thread that was discussing overnight oats. It turns out that lots of people just don’t like the texture of uncooked oats in cold milk. I can get that – there are lots of dishes that you just don’t eat cold, and porridge is toeing the line. Less milk is definitely better, but there are some more things that you can do.

Here are a few things to try if you still don’t like the texture of cold overnight oats.

Add Cruchy Bits

Adding some crunchy toppings can transform a dish of overnight oats. It makes you focus less on the texture of the oats, and instead, it makes a more rounded mouthful.

Try nuts like almonds or pecans, seeds such as sunflower, or crunchy apple pieces.

Add Other Toppings

When putting together a bowl of oats, you can follow a simple formula:

  • A fruit (bananna, blueberry, strawberry, apple)
  • A nut or seed (almond, pecan, chia, coconut)
  • A sweetener – (honey, maple syrup, sugar)
  • A flavoring – (cocoa, cinnamon, peanut butter)

Make sure to add any soft fruit or nuts just before serving. Fruits turn to mush, and nuts go soft if left in the oats for too long.

Topping Combination Ideas

  • Apple, pecan nuts and maple syrup
  • Banana, blueberries and honey
  • Nutella and banana

Eat Them Room Temperature Or Microwaved

The cold oats can be quite refreshing on a summer’s day when a hot bowl of porridge is not what you were after. But if you don’t like it cold, you can leave a single portion on the counter for 20-30 minutes and they quickly come to room temperature.

There is no reason you can’t heat them up in the microwave, which is very quick seeing as they are already soft. All you need is 30-60 seconds in the microwave depending on the size of the portion – enough to heat them through properly. Remember, you don’t need to cook them, so they don’t require as much time heating.

What Oats Are Best For Overnight Oats?

Rolled oats are the best all-rounded due to being a medium coarseness. Quick oats are too fine, and steel-cut oats tend to be too thick and chewy. Rolled oats absorb liquid well and become soft overnight.

I think it’s always worthwhile to spend a bit more money on good oats. The cheaper ones tend to have tough bits, be irregular in sizes, or just don’t taste as good. Considering they are already very cheap, I think it’s a good investment.

Wondering if you can use instant oats for overnight oats? – I wrote an article on how to do that.

Should Overnight Oats Be Refrigerated?

Overnight oats should be refrigerated due to the inclusion of fresh milk which can go sour in warm environments. You can leave your oats at room temperature if soaking for a few hours, but the fridge is best for overnight.

You should treat overnight oats like fresh milk as that is the sensitive ingredient in the recipe. Milk can go sour quickly if left in a hot room but can last hours left outside in a cool space. Use your judgment and always use the fridge for extended periods.

How Long Do Overnight Oats Last?

Overnight oats last about four days in the fridge. They are best after one day and then slowly become softer over time until they are almost liquid like a smoothie.

The great thing is that you can make a big batch on the weekend, and have breakfast sorted for most of the next week. You can either use one large food container or divide it into individual jars with a lid.

Can I Eat Overnight Oats After 1 Hour?

You can eat overnight oats after any amount of soaking time and will see some softening of the oats after 1 hour. They are better with at least a few hours of soaking in liquid before eating – and best overnight.

I still enjoy eating oats freshly mixed with milk and a handful of raisins – that is the most simple muesli. I use good quality rolled oats that aren’t too coarse, so don’t require any cooking or soaking to become palatable.

Depending on the coarseness of your oats, 1 hour might be too little to make much difference in texture. At least try about 4 hours, or just mix up the night before and leave in the fridge overnight.


Hopefully, you now have better knowledge to avoid slimy overnight oats. Give them another go if you were like me and didn’t enjoy them the first time. Some key takeaways from this article:

  • Use a 1:1 ratio of milk and oats for better texture
  • Rest at room temperature before eating
  • Top with fruit, nuts and syrup to improve the overall breakfast bowl

Have any questions? Ask me in the comment section below and I’ll get back to you.

Tom Hambly

Tom Hambly is the founder of Boss The Kitchen. With a background in cooking and building websites, he enjoys running this site to help other cooks improve. About Tom Hambly.

2 thoughts on “Why Are My Overnight Oats Slimy? (Get The Ratios Right)

  1. Hello Tom,

    Thanks for this review. I dont like mushy oats and fear I wont like this either. However, you mentioned theres an oat thats softer in texture that you can eat right away with milk.which brand is that please?



    1. Hi Priscilla – any rolled oats work great rather than the jumbo/thick oats – I use Quaker Oats.


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