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EVER since the time of ancient Egypt, people have used sprouted cereal grains – malt – to make beer. For bakers, malt is also a secret ingredient that helps bread rise perfectly and develop an attractive brown crust.

Cereal grains are packed with starch, a complex carbohydrate made up of long, branching chains of glucose molecules. It is a source of stored energy for the embryonic plant to grow. But in order for cells to make use of that energy, the starch has to be broken down into small sugars consisting of one or two glucose molecules.

In the 19th century, chemists discovered that malted barley contains a chemical with the power to convert starch into glucose. This was the first enzyme to be discovered, and they named it diastase; today, we call it amylase. When seeds germinate, they produce these amylase enzymes to break down starch.

Yeast also needs simple sugars, which it ferments to produce alcohol. It has its own amylase enzymes for breaking down starch, but beer brewers rely on malt because it provides much more amylase, and therefore more food for the yeast.

Malt is useful to bakers for the same reason: amylase enzymes provide a ready source of food for the yeast that leavens bread. This is particularly helpful if you have a long proofing stage – for example, if you are fermenting pizza dough in the fridge for several days.

The extra sugars in the dough help develop a nice brown colour on the outside of buns or bagels. You can buy diastatic malt powder from baking suppliers. They may also sell a non-diastatic version, but this doesn’t contain active enzymes – it is just for flavour.

Or, you can buy whole barley grains and make your own malt. First, soak them in cold water overnight. In the morning, skim off any floating detritus, then drain the grains and spread them out on a tray. That evening, repeat this process: soak overnight, drain and spread out. By now, you may see rootlets growing out of the grains (pictured). Spray them with water and turn occasionally to expose them to air.

In barley, the acrospire (a plant’s shoot), starts growing inside the kernel. Once a day, cut a single grain lengthwise to check its growth. When the acrospire is nearly as long as the grain’s kernel, dry the grains to stop them growing. Place them in a warm spot – near a radiator, say – but not too warm, as the enzymes will be destroyed above 50°C (122°F).

Once they are completely dry, grind the grains with a mortar and pestle or spice mill to make diastatic malt powder. Try adding a small amount – about 1 per cent of the weight of the flour – the next time you make bread.

If you are a home brewer, you might try roasting your malt and adding it to flavour beer. Brewers use base malt, containing active enzymes, and roasted malt.

Sam Wong is assistant news editor and self-appointed chief gourmand at ¿ìè¶ÌÊÓƵ. Follow him @samwong1

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