Diastatic malt powder is only used when working with unmalted flour or when using high percentages of pre-ferments, such as biga and poolish. The powder is made from wheat that has been sprouted, dried, and finely ground. With this method, the wheat will contain lots and lots of enzymes. These enzymes break down the starch in the flour and turn them into simpler sugars. When adding diastatic malt to the dough, these extra sugars will caramelize during the baking and give your pizza a beautiful brown color!
Diastatic malt powder is beneficial when you bake your pizza at lower temps, such as in a home oven. Because of the low temperatures, the crust barely browns, so you may opt to add some diastatic malt to the dough. When baking at higher temperatures as is required for Neapolitan pizza, the usage of diastatic malt is not recommended. Because malt powder contributes to the browning of the pizza crust, the crust will burn when baking at excessive temperatures.
Use diastatic malt sparingly, as too much can lead to over-fermented dough, burnt crust, and an unpleasantly sour taste. Use the amount stated on the packaging — remember, less is more!
Depending on how you’re making dough, you add malt directly to flour or water. When mixing by machine, it’s best to add the malt directly to the flour so it can be distributed properly. When kneading a dough by hand, start by adding the water to a bowl, followed by the diastatic malt powder, yeast, and about 10% of the flour. Give this a mix before adding the salt. Continue to mix and knead the dough, adding some of the flour at intervals until you have obtained a smooth dough.
Always check the ingredient list: if “malted barley flour” or “enzymes” is listed in the ingredients statement, it is malted. Malted flour is common in the United States, whereas in Europe it is uncommon to find malted flour in shops. Tipo 00 flour, which is what Pieter uses for his pizza doughs, is traditionally unmalted.
Diastatic malt can be added to any unmalted flour. The baking aisle of a supermarket is a good place to start your search for diastatic malt powder; look near the flours and bread ingredients.
When you make a pre-ferment (consisting of flour, yeast, and water), the yeast will feed on almost all the sugars from the flour. If you were to use this pre-ferment in your dough, you will have a dough with very few sugars left. This would result in a pale pizza crust. By adding diastatic malt to the dough, you are basically adding extra “sugar,” which will caramelize and color your crust while it is baking.
If you prefer to cold ferment your dough for a few days, you may find that your pizza crust becomes a little pale. This is because the yeast has eaten most of the sugars. For that reason, you can add some diastatic malt powder to the dough, which will help with browning the crust.