A loaf that will not brown has run out of sugar

Treat the sections below as a sequence. With pale crusts on bread, getting the early decisions right makes the later ones much easier.

What browning actually needs

The colour on a crust comes from reactions between sugars and proteins, which require heat and a surface dry enough to exceed boiling temperature. Those sugars come partly from the recipe and partly from flour enzymes breaking starch down during fermentation. Yeast consumes sugars as it works, so a dough that has fermented for a very long time has less left over.

The crust surface has to dry before it can climb past the temperature at which browning begins. Any of those three conditions failing gives you a pale loaf, and the diagnosis is a matter of working out which.

The overfermented pale loaf

A dough taken far past its peak has had its available sugars consumed, leaving nothing at the surface to colour. Such loaves are usually pale, flat and slightly sour, and they often have a coarse, weak crumb as well. The fix is a shorter bulk fermentation or a cooler dough rather than anything to do with the oven.

The dough tells you first: reducing the yeast and keeping the same schedule achieves the same thing if the timings suit you better. A loaf that was pale and also spread sideways is almost certainly this case rather than an oven problem.

The steam that stayed too long

Steam early in the bake keeps the surface flexible so the loaf can expand, which is exactly what you want at first. Left in place for the whole bake, that same moisture prevents the surface drying and therefore prevents browning.

Removing the lid or venting the oven partway through is what allows the crust to dry and colour. A loaf baked in a covered pot for its entire time comes out pale and slightly soft for this reason. The correction is simply to uncover it for the later part of the bake rather than to raise the temperature.

Oven temperature and time

An oven running cooler than its dial claims produces a bake that is dry inside and pale outside. A separate thermometer settles this question in one bake, and the offset is often larger than expected. Fan ovens dry the surface faster and generally brown well, so a pale loaf in a fan oven points elsewhere.

In the tin, extending the bake without raising the temperature dries the crumb before it colours the crust.

A short blast of higher heat at the end colours a pale loaf without overbaking the interior.

Flour and recipe factors

Flours differ in enzyme activity, and one with low activity produces fewer sugars during fermentation. This is why some bakers add a small amount of malted flour, which supplies the enzymes the flour lacks.

Doughs containing milk, sugar or egg brown far more readily, which is why enriched loaves rarely have this problem. A lean dough of flour, water, salt and yeast is the hardest case, since it has the least to work with. Brushing the surface with water rather than a wash gives crispness but adds nothing that helps it colour.

Weigh rather than scoop wherever a recipe leaves you the choice.

Working out which cause you have

Pale and flat with a sour smell means overfermentation, and the answer is earlier in the process. Pale and soft with a slightly wrinkled surface means steam was present too long. Pale, dry and hard means an oven that is cooler than it claims or a bake extended too far.

Pale with an otherwise perfect crumb and rise usually means a low enzyme flour or a very lean recipe. Changing one of these per bake is the only way to be certain which one was responsible.

The takeaway

Work out whether the sugars were eaten, the surface stayed wet, or the oven never got hot enough.

Temperature and time are the same argument held at opposite ends.