USEFUL INFORMATION

Science of bread making

If you've ever wondered what it is that gives bread its light, palatable texture; or, how it is that bread comes to rise - then read on for a basic guide to the science of bread making.

Bread rises as the gas (Carbon Dioxide or CO2) produced from the fermenting yeast becomes trapped in the dough. As more gas is released it needs more space and hence the dough is pushed upwards and outwards. In other words it rises. When bread is finally baked, the heat kills off the yeast, stops fermentation and the production of gas and the starch in the flour sets maintaining the risen structure and airy texture of the bread.

For your dough to stretch effectively, it needs to have an elastic texture. The essential ingredient that gives this texture is the flour. Strong bread making flours contain high levels of gluten which is essential to make an elastic dough. This is why only strong bread flours can be used for bread making.

So what about the gas? We know this is produced by fermentation, but what does that mean? Active yeast, when it is mixed into a dough with warm liquid, is given all the basic life support it needs - food, moisture and warmth. Immediately feeding on the sugar in the mix or even on the starch in the flour the yeast multiplies.As it does this Carbon Dioxide and alcohol are produced, and while the alcohol evaporates, the carbon dioxide makes the bread rise. This process is called fermentation.

The important thing about this whole process is to remember that yeast needs its life support system to work. Without optimum warmth, food and moisture it will not grow and the bread will not rise. Extremes of temperature will damage yeast - very cold conditions will make it inactive and very hot conditions will destroy it. The best temperature for yeast to reproduce is 25-28°C and in a moist environment.

Once bread dough has been mixed and kneaded it can be refrigerated for up to five days, providing there are no perishable ingredients in the mixture. If your dough contains perishable ingredients it can be stored in the freezer for up to three months, but once thawed should not be kept at room temperature for any longer than two hours.