Naturally gluten-free grains and starches, and the oats question

Published 2026-10-21, updated 2026-10-21

Cooking gluten-free does not have to mean buying a long list of specialist products. Many everyday grains, seeds and starches contain no gluten at all, and they are also plant-based, so they fit a vegan kitchen too. The trouble is that a few grains look harmless but are close relatives of wheat, and that even a naturally gluten-free grain can pick up gluten between the field and your pan. This guide sorts grains and starches into groups, explains the oats question, and shows where each one fits in cooking.

What gluten is and where it comes from

Gluten is the name for a group of proteins found in wheat, barley and rye. When wheat flour is mixed with water, these proteins form the stretchy network that lets bread rise and gives pasta its chew. Because the proteins come from three specific cereals, the practical rule for a gluten-free cook is simple: wheat, barley, rye and anything derived from them are out, and most other grains and starches are naturally fine.

Wheat has many names, which is where people get caught out. Spelt, khorasan wheat (sold as Kamut), emmer, einkorn, farro and durum are all types of wheat. Semolina, couscous, bulgur, freekeh and seitan are all made from wheat. Triticale is a cross between wheat and rye. None of these is gluten-free, whatever the packaging suggests about being an ancient or wholesome grain.

Grains, seeds and starches that are naturally gluten-free

The items in this table do not contain gluten in their natural form. Some are true cereal grains, some are seeds that are cooked like grains, and some are starches or flours made from roots and pulses.

Naturally gluten-free grains, seeds and starches
Ingredient	What it is	Where it fits in cooking
Rice (white, brown, wild blends, glutinous)	Cereal grain. Glutinous or sticky rice is gluten-free despite the name.	Side dishes, pilaf, risotto, rice noodles, puddings, and rice flour in baking blends.
Maize (corn)	Cereal grain. Cornmeal, polenta, masa and cornstarch all come from it.	Polenta, tortillas made only from masa, cornbread, and cornstarch as a thickener.
Millet	Small cereal grain.	Porridge, pilaf, and a mild base for patties. Cooks soft and fluffy.
Sorghum	Cereal grain.	Cooked whole like rice, popped like corn, or milled into flour for baking.
Teff	Very small cereal grain.	Porridge, and the flour traditionally used for injera. Check that any injera you buy is made from teff only, as some are blended with wheat.
Buckwheat	Seed of a plant unrelated to wheat, despite the name.	Groats as porridge or pilaf, flour for pancakes. Check that soba noodles are 100 percent buckwheat, as many contain wheat flour.
Quinoa	Seed.	Rinse before cooking. Salads, bowls, stuffings, and as a rice alternative.
Amaranth	Seed.	Porridge, or added in small amounts to baking.
Cassava, tapioca, arrowroot	Starches from roots.	Thickening sauces and fillings, and adding chew to gluten-free breads and bakes.
Potato starch and potato flour	Starch or flour from potatoes. They are not interchangeable.	Starch lightens bakes and thickens; flour is heavier and absorbs more liquid.
Chickpea and other pulse flours	Ground dried pulses.	Flatbreads, fritters, egg-free batters and binders, and flavourful additions to flour blends.
Nut and seed flours	Ground almonds, other nuts and seeds.	Baking and coating. Not suitable for anyone with a nut or seed allergy.

The gluten-free flour blends guide on this site shows how several of these are combined into an all-purpose mix for baking.

Grains that contain gluten

These are the ones to avoid completely when cooking gluten-free:

Wheat in all its forms: plain and wholemeal flour, bread flour, durum, semolina, spelt, khorasan wheat, farro, emmer, einkorn.
Wheat-based products: couscous, bulgur, freekeh, most pasta, seitan, and vital wheat gluten.
Barley, including pearl barley, barley flakes and barley malt.
Rye, including rye flour, rye bread and crispbreads.
Triticale, the wheat and rye cross.
Oats, unless they are specially produced and labelled gluten-free. The next section explains why.

Wheat starch deserves a mention. It is sometimes used in products sold as gluten-free, but only in specially processed forms that meet a labelling rule. Never assume a starch is safe because it is a starch; if a recipe or product says wheat starch, look for a clear gluten-free label or leave it out.

The oats question

Oats are a special case, and it helps to separate two different issues.

The first is contamination. Oats themselves do not contain the gluten proteins of wheat, barley and rye. But oats are often grown in rotation with those crops, harvested with the same machinery, and milled in the same facilities, so ordinary oats frequently contain stray grains of wheat or barley. That is why standard rolled oats, oat flour and many oat milks are not considered gluten-free. Some producers grow and process oats in a way that keeps other grains out and test the result, and these are sold with a gluten-free label. If you are avoiding gluten, choose oats that carry that label, rather than oats that merely say wholegrain or pure.

The second issue is the oat protein itself. Oats contain a protein called avenin, which is similar to gluten proteins. Most people with coeliac disease tolerate gluten-free oats, but a minority react to avenin as well. This means that labelled gluten-free oats are not automatically right for everyone with coeliac disease. If you have been diagnosed, or suspect you have coeliac disease, ask your doctor or dietitian whether and when to include oats, and do not start eating them on your own while you are being tested or recovering.

For a vegan cook, oats are useful for porridge, cookies, crumbles, burgers and as a binder, so it is worth knowing which type you are buying. In the kitchen, treat oat products as a category to check on the label every time, including oat milk, oat flour and granola.

Contamination in other grains and flours

The oat issue is the best known, but the same logic applies to other naturally gluten-free ingredients. Grains, flours and pulses that are scooped from bulk bins, or milled and packed on lines that also handle wheat, can pick up gluten. Lentils and rice can have stray wheat or barley grains mixed in from the field. Buckwheat and millet flours can be milled in facilities that also handle wheat.

Three habits reduce the risk. Buy packaged rather than loose products, and prefer ones that carry a gluten-free label if you need to avoid gluten strictly. Read the allergen statement for wording like may contain wheat. Sort and rinse dry lentils, rice and similar ingredients before cooking, which helps remove stray debris but is not a guarantee. Anyone with coeliac disease should ask their dietitian how careful to be about unlabelled ingredients.

Cooking tips for the naturally gluten-free grains

Rinse quinoa under running water before cooking to wash off its natural bitter coating.
Toast buckwheat groats and millet briefly in a dry pan before adding liquid for a nuttier flavour and a less mushy result.
Cook whole grains in plenty of liquid and check the packet for the ratio and time, since varieties differ.
Cooked and cooled rice, millet or polenta can be fried, pressed into patties or sliced for pan-frying; they firm up as they cool.
In baking, do not swap one gluten-free flour for another one to one. Different flours absorb different amounts of liquid, which is why blends are normally weighed.

A vegan, gluten-free meal can be built from a grain, a pulse and vegetables, for example rice with lentils, polenta with beans, or millet with roasted vegetables. For ideas on proteins, see the vegan protein swaps guide.

What this guide is based on

Which grains, seeds and starches contain gluten (wheat and its varieties, barley, rye, triticale) and which are naturally free of it is general food knowledge published widely by coeliac organisations and food authorities.
The two oat issues (cross-contamination in growing and milling, and avenin sensitivity in a minority of people with coeliac disease) are general knowledge; we make no claim about any individual's tolerance.
Cooking tips such as rinsing quinoa and toasting groats are general cooking knowledge. None of this comes from our own testing.
This guide is general information, not medical advice. People with coeliac disease or a wheat allergy should follow their doctor, dietitian and national coeliac organisation, and read the label on every product.