Why the Bag Matters More Than You Think

A good loaf is flour, water, salt and time — which means the flour is doing most of the work. Yet a wander down the baking aisle can be quietly confusing: strong, plain, extra strong, wholemeal, brown, seeded, self-raising. They are not interchangeable, and choosing the wrong bag explains a great many dense bricks and crumbly disappointments. The number worth hunting for is protein, because protein is what builds gluten, and gluten is the elastic scaffolding that traps the gas your yeast produces.

British plain flour usually sits around 9–10% protein. Strong bread flour runs from about 12% to 14%, sometimes higher. That gap sounds small. In a dough, it is the difference between a loaf that climbs the tin and one that slumps apologetically.

Strong Bread Flour: The Backbone of a Rise

This is the bag to reach for first. Strong flour is milled from hard wheat, and its high protein content forms a robust, extensible gluten network — the sort that can take a long knead, a slow overnight prove and a hot oven without collapsing. Tin loaves, bloomers, coburgs, pizza bases, bagels and brioche all depend on it.

You will know it is working when the dough turns from a shaggy mess to something smooth and slightly tacky, and stretches thin enough to let light through without tearing — the windowpane test. With strong flour, that usually takes eight to twelve minutes by hand. If your dough springs back into shape when poked, the gluten is developed and ready to prove.

Look out for bags labelled extra strong or very strong. These suit high-hydration sourdough and long, cold ferments, but they can be tight and chewy in an everyday white loaf, so add a little extra water and give them time to relax.

Plain Flour: More Capable Than You Might Expect

Plain flour is milled from softer wheat, and its gentler gluten makes for a softer, shorter crumb. It will make bread — soda bread, flatbreads, bannocks and quick yeasted loaves all work well — but expect a modest rise and a closer texture rather than a tall, airy sandwich loaf.

Check the label rather than assuming. Some plain flours hover near 11% protein and bake surprisingly well; others are deliberately soft and best kept for scones, shortcrust and cakes. If a recipe calls for strong flour and you only have plain to hand, handle the dough gently, knead less, and prove it in a tin rather than free-form, where it has some support.

Wholemeal and Wholegrain: Thirsty, Flavoursome, Slower

Wholemeal flour keeps the bran and wheatgerm, which brings nutty depth and a lovely rust colour — and a set of problems. Bran particles are sharp, and they slice through gluten strands as the dough develops, so a 100% wholemeal loaf behaves like a much weaker flour than its protein figure suggests.

• Add more water. Bran and germ absorb enthusiastically; begin with 5–10% more than a white recipe and keep a jug nearby.
• Give it a rest. A 30–60 minute autolyse — flour and water only — softens the bran and improves the crumb noticeably.
• Blend first. A 70/30 or 60/40 mix of strong white and wholemeal is a forgiving starting point.
• Prove patiently. Wholemeal doughs rise more slowly, so judge by look and feel rather than the clock.
• Store it well. The natural oils in the germ turn rancid within a few months, so keep the bag cool and airtight, or freeze it.

Other Bags Worth Knowing

Self-raising flour contains a chemical raising agent and is almost always made from soft wheat. It is not a substitute for strong flour in a yeasted dough — the two raising systems muddle each other rather than helping. Keep it for cakes and scones.

Rye flour is low in gluten and famously sticky. Use it as 20–30% of a blend for a dense, sour, wonderfully savoury loaf.

Spelt has gluten, but fragile gluten. Knead briefly, prove quickly, and treat the dough kindly.

Italian 00 is finely milled and lovely for pizza and pasta, though its protein varies by brand, so read the back of the bag before you commit.

Matching Flour to the Bake in Front of You

For an everyday white tin loaf, use strong white and nothing else. For a rustic round with real character, blend strong white with around 30% wholemeal. For soda bread or flatbreads, plain flour is perfectly at home. For sourdough, a strong or extra strong white base with a portion of wholemeal or rye gives both lift and flavour.

As a rule of thumb, keep two bags in the cupboard — a dependable strong white and a fresh wholemeal — and blend to taste. Weigh your flour rather than scooping with a cup, store it somewhere cool and dry, and if a bake comes out heavy, look at the flour before you blame your kneading. The right bag, chosen with a little thought, is half the loaf already.