Science of bread

Saccharomyces rereusiae (Bakers Yeast) is a live single cell fungus. There are about 160 species of yeast, many of them live all around us.

At Darvell and Son, we use fresh bakers yeast to make our bread, however most people are familiar with its mass produced form; the beige granules that comes to life when it comes into contact with warm water. Once reactivated, yeast begins to feed on the sugars in the flour and release the carbon dioxide that makes bread rise. Yeast also adds many of the unique and distinctive flavours and aromas of bread.

Leavening agents would be nothing but bubbling brews without something to contain them. This is where flour comes in. There are many different types of flour, but the most commonly used in bread is wheat flour. This is because wheat flour contains two proteins, Glutenin and Gliadin, which when combined with water forms gluten. As a dough is kneaded, the gluten becomes more stressed and increasingly stretchy. This gum like substance fills with thousands of gas bubbles as the yeast works during rising, this is called gluten animation.

The other key ingredient into the mix is starch. This carbohydrate makes up about 70% of flour by weight, when starch granules are attacked by enzymes present in the flour, they release the sugars that the yeast feeds on. Starch also reinforces the gluten and absorbs water during baking, helping the gluten to contain the pockets of gas produced by the yeast.