Why does bread dough rise? How does yeast make dough rise?
Bread is a very common meal ingredient in most cultures. It's used to make sandwiches, breadcrumbs, stuffing, desserts and lots more.
If you've ever made a loaf of bread from scratch, chances are you've wondered how a small mound of dough can almost double in size within just a short amount of time, after being simply left out in the air.
You probably already know that an ingredient called yeast is what causes the dough to rise, making the finished product aerated, spongy and delicious.
However the question still remains - how does yeast make dough rise?
Read on to find out some things about the interaction between bread and yeast.
Be warned, some of this information you may not have wanted to know!
So, Why and How does Yeast make Dough Rise?
There are two types of yeast available for making bread:
- Fresh yeast - Only in a usable state for a short amount of time and needs to be refrigerated.
- Dry yeast - Stored in blocks and bags and longer lasting. Has yet to be activated.
Yeast is a type of fungus that comes life when left in warm bread dough. When active, the yeast begins to feed on the sugars in the dough. The yeast then releases gases caused by the process it uses to break down the sugars after eating them. The gases it release give the dough it's aerated and bubbly texture.
The gases are made of carbon dioxide as well as some ethanol alcohol.
Don't worry though. The yeast will die as soon as it is exposed to cold or heat (either refrigerator or oven). All that is left is the gassy pockets trapped inside the bread.
If you're wondering why bread continues to rise while in the oven, it's because the fungus works harder and faster as it feels the increasing heat. Soon however, it dies.
Why don't some Yeast Breads Rise?
Of course not all bread rises. There are several different ingredients that inhibit the eating habits and life of yeast. These include:
- Animal fat
How do I shorten or lengthen the Rising Time?
If you need to do some chores or are just in a hurry, there are ways to make sure that your freshly made dough rises when you want.
- A warm oven - will speed up the rising process.
- A cool refrigerator - will slow down the process. Cover dough with a damp towel.
Bread dough photo with thanks to grongar on Flickr