The Ultimate Guide to Oat Flour

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My favourite of all the gluten-free flours finally receives its moment in the sun with its very own chapter in my Gluten-Free Flour Series. Ladies and gentlemen, I give you… Oat Flour.

Image of jumbo rolled oats and gluten-free oat flour on a wooden board

First a caveat on oat flour. Oats themselves are gluten-free but are often processed in mills with other grains so there is a lot of cross-contamination. If you are gluten intolerant or coeliac you must make sure it’s certified gluten-free on the label. It’s also the unfortunate fact that some coeliacs and people with a gluten intolerance just simply can’t tolerate oats at all whether they are processed in a gluten-free environment or not. So always check with whomever you are baking for that oat flour isn’t on their black list.

This Chocolate Raspberry Cake is a foolproof gluten-free buttermilk chocolate cake, sandwiched with a simple fresh raspberry swiss meringue buttercream.

Chocolate Raspberry Cake

The benefits of oat flour

Oat flour carries the same benefits as oats themselves which are delicious and nutritious. They are high in a fibre called beta-glucan which helps lower cholesterol, supports your immune system and contributes to fight hunger pangs. The soluble fibres are also considered to lower blood sugar by reducing glucose absorption meaning oats are especially beneficial for diabetics. Oats are also good for your skin which is why you see oatmeal added to lots of skincare products. They are high in protein compared to other grains and are a good source of magnesium too so assist in energy production.

However, this is all just bonus material as oats also taste terrific which is carried through into your bakes and also add texture from beautifully fluffy bakes to flaky pastry.

Gluten-Free Eccles Cakes

Gluten-Free Eccles Cakes

What is oat flour?

Oat flour is basically very finely ground oats. You can easily grind oats yourself to make oat flour but the finer the grind then the fluffier the cake which is why I buy commercial oat flour. However on the very regular occasions which I run out then there is a negligible difference in the homemade version. It’s also the much cheaper way to go.

Image of jumbo rolled oats and gluten-free oat flour on a wooden board

How to make oat flour?

Oat flour is simple to make as all you are required to do is bung a heap of jumbo rolled oats destined for your porridge into the food processor and turn it on. Within about 30 seconds you will have a beautiful oat flour. If you need a specific amount for a recipe then the ratio is 1.25:1 jumbo rolled oats to oat flour so to make 100g of oat flour then you will need 125g rolled oats.

Steamed Chocolate Sponge Pudding with Chocolate Custard {gluten-free}

Gluten-Free Steamed Chocolate Pudding with Chocolate Custard

Can you substitute wheat flour with oat flour?

Now, when I say oat flour is my favourite flour that is not because it is the most versatile. Nor does it provide a direct 1:1 substitution with wheat flour as it barely mimics any properties of plain wheat flour.

Plain wheat flour is so ubiquitous because it does so many jobs that you might need two or three alternative flours to complete. A lot of its work lies in holding things together, crisping or fluffing. Wheat flour also has a neutral taste so can sit well in any meal or bake without imparting any distinct flavour.

However, what makes alternative flours so much more interesting and more complicated to understand is their unique profiles. There isn’t a go-to gluten-free flour, each one brings its own characteristics and ‘role’ to your meal or bake.

It is possible though to create bakes using merely oat flour, although the results will not be as robust as using wheat flour. A delicious cake using just oat flour will need a lot of hand holding with its other ingredients, you will probably need more eggs than a regular recipe to help the cake to rise. However, it will produce a delicate elegant result. Using oat flour by itself can also be very successful in cookies and biscuits. However it’s best to not substitute wheat for oat flour in any old recipe but to seek out recipes which are specifically produced with just oat flour in mind.

Image of jumbo rolled oats and gluten-free oat flour on a wooden board

Why use oat flour?

There are many alternative flours out there so why might you choose to use oat flour in your gluten-free cakes and bakes?

The reason would be for the bags of personality that oat flour brings to the table. There is none of this neutrality that wheat flour carries. Instead oats are imbued with a deliciously toasted butterscotch flavour which is almost sweet and pairs so beautifully with so many flavours and gives a lovely background note to your bake. It’s distinctive but doesn’t overpower.

Oat flour is also higher in protein and fibre than many other alternative flours which means it gives a lovely soft texture to your bakes, it fits perfectly in a homemade gluten-free plain flour blend as it works so well with other alternative flours.

Gluten-Free Red Velvet Cake

Gluten-Free Red Velvet Cake

How do you use oat flour in baking?

There are lots of recipes which benefit from the inclusion of oat flour. In particularly cookies, making them beautifully chewy.

Oat flour also works well in crumbles or crisps due to its crumbly chewy nature.

Strawberry Gooseberry Crumble {gluten-free}

Strawberry Gooseberry Crumble

Oat flour can be put to excellent use in a gluten-free all purpose flour mix and I pair it a lot with white rice flour and tapioca flour which can be substituted for wheat flour in most recipes. The rice flour gives the bake a structural integrity but the soluble fibres of the oats gives the bake a softer quality and negates the grittier properties of white rice flour. The tapioca is an excellent binder and mimics some of the gluten properties of wheat.

This gluten-free Golden Beetroot Carrot Cake is the best carrot cake you will ever taste. Full of sweet earthy goodness thanks to using both golden beetroot and carrots; complex with pecans, sultanas and apples; perfectly complimented with a not too sweet cream cheese buttercream and adorned with the delightful crunch of a salted pecan praline and candied beetroot and carrots.

Golden Beetroot Carrot Cake

What flavours pair well with oat flour?

Take your pick, this is such a versatile flavour. Although its nutty toffee-like tones are an especially good match for chocolate, caramel, vanilla, nuts, spices, stone fruits, berries, bananas, apples, squash and coffee.

Where can you buy oat flour?

Oat flour can be picked up at most health food shops and if I run out that’s where I head to. However, like all alternative flours it can be expensive so I find the most economical way is to buy it online. I go through bags of the stuff as it’s the flour I use most regularly so I like to buy in bulk. My favourite brand is Bob’s Red Mill Gluten Free Whole Grain Oat Flour 400 g (Pack of 4) at a reasonable price. Even better if you go the subscribe and save option.

If you wanted to make your own oat flour…

I would be nowhere without my Magimix 4200XL Food Processor – Satin when I want to grind my own oat flour. I have easily had it over ten years and I use it nearly every day for all manner of kitchen jobs like whipping up dips, pestos, nut butters and flours and making my breadcrumbs. The Magixmix is an impressive piece of kit which even survived being dropped when we moved into our house (although it did have to have the motor replaced but that wasn’t too expensive). I put all the attachments in the dishwasher and they come out brilliantly clean but it also gives just great results. I love my Magimix and along with my Kitchenaid is the piece of equipment I use most often in my kitchen.

The links above are affiliate links so if you decide to buy anything using the links given then I will get a small commission from Amazon at no cost to you. To learn more about how the data processing works when using these Amazon affiliate links then please visit my privacy policy page.


Text saying Guide to Gluten-Free Flours: Oat Flour. In front of an image of some oats and oat flour


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  1. A question about this comment:
    “If you need a specific amount for a recipe then the ratio is 1.25:1 jumbo rolled oats to oat flour so to make 100g of oat flour then you will need 125g rolled oats.”
    125g of rolled oats, when milled into flour, would still weigh 125g, wouldn’t they?… Although milling would increase the volume.
    Or do you mean that if a recipe calls for 100g regular flour, you would need 125g oat flour to substitute?
    Thank you for your kind attention to my questions.

    • I recommend if you need a specific amount for a recipe then just start with the 1.25:1 ratio. You can weigh the oat flour again after it has been milled, but it tends to lose a bit of its weight in the grinding process – sticking to the processor blades etc. It’s always super accurate if you just weigh it again before adding to your recipe so you can be sure you’re adding the exact right quantity of oat flour.

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