Quick & Easy

Overnight oats: the ratio matters more than the recipe

Overnight oats are a ratio, not a recipe. Get the oats-to-liquid balance and the oat type right and you never need a recipe again.

By Updated 5 min read
A bowl of softened rolled oats, the base for overnight oats.
Photo: Bodhi Peace, via Wikimedia Commons (CC BY-SA 4.0).

Key takeaways

  • Use roughly equal volumes of rolled oats and liquid.
  • Rolled oats hydrate in cold liquid; steel-cut oats do not.
  • Four hours is enough time; overnight is convenience.
  • Salt matters more than the sweetener.
Prep time
5 min
Total time
5 min
Servings
1

Overnight oats get written up as a recipe, which is the wrong frame. It is a ratio with things added to it. Once you know the ratio, you stop needing recipes, and you stop producing the two failure modes that put people off: the bowl of wallpaper paste and the bowl of cold soup.

The ratio

One part rolled oats to one part liquid by volume, plus a spoonful of something thick. That is it.

In practice, for one person: 50 g of rolled oats (about half a cup), 120 ml of milk or a plant alternative, and a heaped tablespoon of yoghurt. Weigh it once, look at it in the jar, and after that you can do it by eye for the rest of your life.

The oats-to-liquid ratio, and what happens either side of itA scale of liquid per one part of rolled oats. Below about three quarters the oats cannot fully hydrate and stay chalky in the middle. One part liquid to one part oats is the target. Up to one and a quarter gives a looser result. Past one and a half the oats stop holding the liquid and the jar separates. Below, three oat types are compared: rolled oats work, instant oats break down into paste, and steel-cut oats will not soften without heat.Liquid, per one part rolled oats by volumechalky centreTHE RATIO50 g oats, 120 ml liquidlooser, still holdsseparates in the jar0.751.01.251.5Plus one heaped spoonful of something thick — yoghurt, skyr or a tablespoon of chia — to stop it pooling.Check the packet before you change anything elseROLLED OATSSteamed and flattened.Absorb overnight andstill hold their shape.Use theseINSTANT / QUICKCut finer, pre-cookedfurther. Absorb too fastand break down to paste.Cut liquid by a quarterSTEEL-CUTBarely processed. Willnot soften in a fridgeovernight.These need heatMost of the absorption is done in about four hours, so overnight is a convenience rather than a requirement.
Weigh it once and look at the jar; after that the ratio can be judged by eye. If a batch has ever come out gluey, the oat type is the first thing to check, not the quantities. Diagram by HRITU.

If you like it looser, go to one part oats to one and a quarter parts liquid. Past one and a half, the oats stop holding it and you get a separated jar. Below about three quarters, the oats cannot fully hydrate and the texture stays chalky in the middle.

Why the oat type decides everything

This is the single most common reason overnight oats disappoint, and it is almost never mentioned.

  • Rolled (old-fashioned) oats. The right choice. Steamed and flattened, so they absorb overnight and still hold their shape.
  • Instant or quick oats. Cut finer and pre-cooked further. They absorb far too fast and break down into paste. If this is what you have, cut the liquid by a quarter and eat them within a few hours.
  • Steel-cut oats. Barely processed. They will not soften in a fridge overnight, and you will be chewing raw grain. They need heat.

If your overnight oats have ever come out gluey, check the packet before you change anything else.

Why the thick spoonful matters

Yoghurt, skyr, or a tablespoon of chia does two jobs. It thickens the free liquid so the mixture holds together rather than pooling, and in the case of yoghurt the acidity gives the whole thing a lift that plain milk and oats does not have. Without it you tend to get a jar that tastes flat and looks separated by morning.

Chia is the strongest thickener of the three. One tablespoon in a jar this size is plenty; two and you are eating pudding.

Timing, and what actually happens overnight

The oats are absorbing water and the starch is hydrating. Most of that is done in about four hours, which is why overnight oats made at eleven at night and eaten at seven are no better than ones made at six in the morning and eaten at lunch. Overnight is a convenience, not a requirement.

They keep well for three days in the fridge. Past that the texture keeps softening and fresh fruit stirred through starts to weep.

What to add, and when

  • The night before: oats, liquid, yoghurt or chia, a pinch of salt, cinnamon, vanilla, cocoa, and any dried fruit that benefits from softening.
  • In the morning: fresh berries, banana, nuts, seeds and anything crunchy. Nuts added the night before go soft, and banana added the night before goes grey and overwhelms everything else.
  • Sweetener: add it the night before if you use honey or maple, because it needs stirring through properly and cold oats resist it.

The pinch of salt is not optional in the way it sounds. Unsalted oats taste washed out, and a small pinch is the difference between a jar you finish and one you leave.

Three combinations that work

  • Apple and cinnamon. Grated apple stirred in overnight, cinnamon, a spoonful of yoghurt, walnuts in the morning.
  • Cocoa and banana. A teaspoon of cocoa and a little maple overnight, sliced banana and a pinch of flaky salt on top in the morning.
  • Mango and cardamom. A crushed cardamom pod and yoghurt overnight, fresh mango in the morning. Best in season, when the fruit does the sweetening for you.

If you are making this tomorrow

For a hot breakfast in roughly the same amount of time, see the masala omelette.

Ingredients

  • Base
  • 50 g rolled oats
  • 120 ml milk or a plant milk
  • 2 tablespoons yoghurt
  • Pinch of salt
  • Optional
  • 1 tablespoon chia seeds
  • 1 teaspoon honey or maple syrup
  • Fruit, to serve

Instructions

  1. Stir the oats, milk, yoghurt and salt together in a jar.
  2. Add the chia seeds if using, and stir again after a minute so they do not clump.
  3. Cover and refrigerate for at least four hours.
  4. Stir before eating, loosen with a splash of milk if it has gone too thick, and add fruit at the last moment.

Recipe tips

  • The pinch of salt is not optional. Without it the whole thing tastes flat.
  • Add fruit in the morning rather than the night before; berries bleed and banana goes brown.
  • If it is too thick, that is a liquid problem, not a mistake.

Storage

  • Keeps two days covered in the fridge. Do not freeze.

Frequently asked questions

No. Oat, soy and almond milk all work at the same ratio. Soy thickens the most because of its protein content; almond is the thinnest and you may want to drop the liquid slightly. Coconut milk from a tin is much richer than the cartoned drink, so treat it as half liquid, half thickener.

Yes. Thirty to forty seconds in a microwave, stirred halfway. They will thicken further as they heat, so add a splash of extra milk first.

Oats are a good source of soluble fibre, and a jar like this with yoghurt and fruit is a reasonable breakfast. What determines the answer is the sweetener. Three tablespoons of maple syrup and a handful of chocolate turns it into dessert, which is fine, but it is dessert.

HRITU Editorial Desk is the byline for pieces produced in-house by the HRITU editorial team. We write about cooking, travel, science and everyday knowledge, and we explain the reasoning behind what we publish rather than just stating conclusions. Every article is checked against primary or reference sources before it goes out, dated on publication, and updated in the open when we learn something is wrong. Corrections and questions are welcome at info@hritu.com.

All articles Website

Join the discussion