Gluten-free: the pantry, the rules, and what actually swaps

Gluten is two proteins that, once wet and worked, link into an elastic net. That net is what traps gas in bread, what makes pasta chewy instead of crumbly, and what lets a dough be stretched instead of tearing. Take it out and you have not removed a flavour — you have removed a structure. Everything that follows is about replacing a structure.

This is why swapping flour one-for-one usually fails. It is not that the substitute tastes wrong. It is that nothing is holding the thing together.

What each flour is actually doing

Rice flour is the body: cheap, neutral, and the bulk of most blends. On its own it is gritty and sandy, which is the single most recognisable fault in bad gluten-free baking. Buy it finely milled, and let batters rest so the grains hydrate.

Starches — tapioca, potato, corn are the chew and the stretch. Tapioca in particular gives that slight pull that makes bread feel like bread. Too much and you get gummy; none at all and you get sand held together by hope.

Sorghum, millet, oat, buckwheat are the flavour and the softness. A blend that is only rice and starch tastes of nothing. These are what stop it tasting like a substitute.

Xanthan gum is the net. A quarter teaspoon per cup of flour for cakes, half for bread. It is doing the job gluten did, and it is the ingredient people leave out and then wonder why the loaf collapsed. Too much and it goes slimy and heavy — this is one where more is emphatically not better.

The rules that actually hold

Hydrate more, and rest. Gluten-free flours drink more water and take longer to do it. A batter that looks right immediately is usually too thick once the rice flour has caught up. Twenty minutes of rest fixes more gluten-free baking than any other single change.

Do not be afraid of a wet dough. Gluten-free bread dough should look like thick batter, not like a kneadable ball. There is no gluten to develop, so there is nothing to gain from a stiff dough and everything to lose.

Weigh things. Flour blends vary enormously in density, and cup measures of rice flour and tapioca starch are not interchangeable by volume even when the recipe pretends they are.

Do not knead. There is nothing to develop. Mix until combined and stop.

The four that hide

These are the ones that catch people who have been doing this for years.

- Soy sauce is made with wheat. Tamari usually is not — check the bottle, because "usually" is doing real work in that sentence. - Oats are naturally fine and almost always cross-contaminated in milling. Certified oats exist and cost more for exactly that reason. - Stock, bouillon and gravy granules are thickened with wheat flour more often than not. - Beer, and anything deglazed with it. Also malt vinegar, and anything called "malt".

And one more that is not an ingredient: shared equipment. A toaster, a fryer, a flour-dusted board. If it matters medically, it matters here more than any label does.