Which Oats for Overnight Oats, and How Long to Soak?
Use porridge oats: in the UK they are rolled oats, the standard oat for overnight oats. Soak them in the fridge overnight, about 8 hours; Flahavan's gives 2 hours as the shortest soak.
Porridge oats are what we use in the OATOLOGY kitchen, and what our lid was weighed with.
Can you use porridge oats for overnight oats?
Yes. In the UK, porridge oats are rolled oats, and rolled oats are the standard oat for overnight oats. Mornflake, a UK oat miller, says porridge oats are milled and rolled into flat-shaped flakes, and Flahavan's lists its Progress Oatlets as Rolled Oats.
In the OATOLOGY kitchen we use porridge oats, and our lid was weighed with them: milk to the line (150ml), then one slightly heaped lid of oats (about 50g) and 1 tbsp chia seeds, as in our basic overnight oats recipe.
Our porridge oats of choice are Flahavan's Irish Porridge Oats, from a brand we rate.
Which oats are best for overnight oats?
Porridge or rolled oats are the standard. Jumbo and quick oats work too, with small changes, and we do not recommend steel-cut oats. Here is each kind as UK packs name it.
| On the pack | What it is | For overnight oats |
|---|---|---|
| Porridge oats or rolled oats | Oats rolled into flat flakes. | Yes, the standard. Sets thick and creamy by morning. |
| Jumbo oats, or jumbo porridge oats | Larger, thicker flakes. | Yes. Stays chewier. Give it the full 8 hours. |
| Quick, superfast or instant oats | Smaller, thinner flakes, made to cook fast. | Yes, with a little less milk. Absorbs faster and sets softer. |
| Steel-cut oats, pinhead oats or coarse oatmeal | Cut or ground into small pieces, not rolled into flakes. | Not recommended. Stays hard on an overnight soak. |
Need it gluten free? Use oats labelled gluten free, and check every other label.
How long do overnight oats need to soak?
Overnight, about 8 hours, in the fridge. That is how we make ours: a full night gives the oats time to take up the milk, and by morning the jar has set thick and creamy.
Short of time? Flahavan's gives 2 hours in the fridge as the shortest soak for its overnight oats.
Jumbo oats want the full night. Their bigger flakes absorb more slowly and stay chewier, so give them the full 8 hours.
Whatever the oat, soak it in the fridge at 5°C or below, never on the worktop. How long a finished jar keeps is a separate clock: our guide to how long overnight oats last goes day by day.
Do overnight oats need to be cooked?
No. Overnight oats soften in the fridge without any cooking. The millers we checked steam their oats as they make them: Mornflake says oats have to be stabilised by gentle steam during milling, and Flahavan's says it rolls, kilns and steams its oats.
The NHS publishes an overnight oats recipe that soaks porridge oats in the fridge overnight, with no cooking.
The rule that matters is the fridge. Milky food should sit at room temperature for no more than about 2 hours, so seal the jar and chill it straight away. Left out on the side overnight? Bin it.
Steel-cut or pinhead oats are a different case: they are cut, not rolled, and we do not recommend them for a no-cook jar, so follow the cooking instructions on the pack.
Do different oats need different amounts of milk?
Only quick or instant oats take a little less. Porridge, rolled and jumbo oats all take milk to the line (150ml) for about 50g of oats, plus 1 tbsp chia, and jumbo oats can take an extra 10ml for a softer set. Our overnight oats ratio guide has the amounts, plus water and batches, and our overnight oats calories guide has the numbers for each milk.
The lid on our overnight oats jar was weighed with porridge oats. It measures by volume, so a lidful of jumbo or quick oats can weigh more or less. If you switch, weigh a lidful once on kitchen scales and aim for about 50g.
Milk to the line, then one slightly heaped lid of porridge oats and 1 tbsp chia. Stir right to the bottom, seal, and give it a night in the fridge.
Your questions
What is the UK equivalent of rolled oats?
Porridge oats. A recipe that asks for rolled or old-fashioned oats wants the same flakes UK shops sell as porridge oats: Mornflake says traditional rolled oats are also known as old-fashioned oats.
Can you use steel-cut oats for overnight oats?
We do not recommend them for a no-cook jar. Steel-cut oats, also sold as pinhead oats, are cut into pieces rather than rolled, and they stay hard on an overnight soak.
Do overnight oats need to be covered?
Yes. Cover or seal them before they go in the fridge, as the NHS recipe does. A loosely covered bowl works for one night, but the top dries out, so we seal ours.
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