Sugar in Bread: For the nerds
Adam Robinson
This is about yeast. It’s not all about yeast but sometimes you have to care for your fungi.
Yeast feeds on simple sugars. We don’t add sugar to our breads, but carbohydrate is a complex sugar and, as such, inaccessible to yeast. But some of the starch, in the milling process, is broken into simple sugars. Additionally, when hydrated during the dough making, enzymes are activated that break down the complex carbohydrate sugars into simple sugars. The most common of these enzymes is amylase, which produces mostly maltose and glucose.
This is why grain, mostly in the form of barley, is malted for beer brewing. To malt grain, it is soaked and kept damp until it starts to sprout. The amylase is activated and turns the starch into simple sugars where it becomes accessible to the fast growing new plant. The brewers want to stop this growing process but retain the active amylase. This is done by drying out the sprouted grain at a low temperature. The result of this is added to the brewer’s mash where the active enzymes rapidly convert the carbohydrate into accessible sugars and the yeasts runs riot producing alcohol and CO2.
I don’t know if any of you have masticated a mouthful of rice or bread for an extended period. It starts to taste distinctly sweet. This is because our saliva contains amylase and is the start of our internal digestive process. It is also why beer is often made with the help of some chewed grain or a good spit into the porridge.
How does this help with bread?
We use stone ground flour that has no additives or ‘improvers’. Most industrial flour will contain additives and enzymatic improvers. Our flour can also change according to the season or the mill’s feedstock. Occasionally the flour can be short of free simple sugars for one reason or another. In addition to this, to encourage bacterial fermentation, our doughs are all slow and long fermented so there is a distinct possibility that they can become exhausted. That is all the accessible food for the yeast has been used. To overcome this we sometimes use something called diastatic malt flour. Diastatic meaning that the malted (sprouted) grain has been dried at a low temperature to preserve the amylase enzymes. As opposed to non-diastatic where the flour (or syrup) is used for flavouring. This malted flour can come from any seed but usually it is barley.
The obvious next step to using diastatic malt flour is to produce our own. We are in the habit of adding sprouted rye seeds to our 100% rye (on Wednesdays) and our sprouting house-milled sourdough (on Mondays). So sprouting seeds has already been part of our weekly schedule. To make our own diastatic malt flour, we have been sprouting wheat seeds and drying them out at a suitably low temperature, essentially below 40°C and then grinding the dried berries into flour in our little mill.
If you’re keen to try it in your home baking, we can sell you some of our diastatic malt flour, but you only need to add a teaspoonful of the flour to your dough. Any more and the bread can get gummy; too much carbohydrate can get converted to simple sugar before baking.
As a bonus, the increased simple sugars in the dough help produce a golden brown crust.
