Grain Chain Episode 7: Yeast and Gluten!

George has popped into the school lab to look at how yeast helps bread rise!

Every ingredient in dough affects how bread rises and cooks, so it’s important to understand all about them. Can you remember all the ingredients?

Flour, water, yeast, vegetable fat, and salt!

They are the basic elements but there’s more going on than you might think. Let’s get in closer with the microscope to see the yeast at work!

It’s like loads of tiny smooth balls… Yeast is a micro-organism, one of the tiniest forms of life – it’s part of the fungi family in fact. There are all sorts of yeasts and they’re everywhere – on our bodies – even IN our bodies and all around us in the air too.

Strange right? You’re breathing something that helps to make bread!

If yeast is placed in warm, damp surroundings with starchy or sweet matter, it’ll start to multiply.

All this activity produces alcohol and a gas called carbon dioxide – and it’s this gas that adds the air to the dough, creating bubbles that makes it grow in size.

The yeast used by bakers is called Saccharymosa cereviserae. Sounds a bit like a magic spell doesn’t it!

In fact, I think yeast IS pretty magical! It’s made in labs and can be in a liquid or dried form.

Bakers mostly use the dried stuff. It’s like a powder, which makes it really easy to move around and store – which helps when you’re making 12 MILLION loaves every day.

The important bit is that yeast is a living thing and if the liquid it’s mixed with is too cool, the yeast won’t multiply. And if it’s too hot – the yeast will be killed.

Don’t worry, it isn’t alive in THAT way! Another clever bit of science you find in bread is the important protein found in flour, known as gluten. It’s incredibly stringy stuff.

It may seem a bit weird but gluten helps make the dough soft as well as strong. Soft – so that the dough can expand when the yeast bubbles form, and strong – so that these gas bubbles don’t burst!

Without gluten, your bread wouldn’t be fluffy and the holes would be smaller – more like what you’d get in a slice of cake.

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