The Science of Yeast
What is Yeast?
Yeasts are micro-organisms, these are a type of fungi but
are different from mushrooms and mould as they are
single cell organisms. Yeast grow as single cells that divide
by budding.
Can you see the scars can be seen on the surface of the
yeast cell where buds have broken off?
Yeast Science
Growing yeast love to eat sugar and starches, like the ones
in bread flour. When they eat these starches, some of the
proteins in the flour, called glutens, swell up.
Yeast eating starch make a gas called carbon dioxide that form
lots of tiny bubbles in the bread dough. The tiny bubbles pop during
baking, but leave tiny holes where they were.
You can see these holes in the bread you eat.
Yeast is also used to make the alcohol in beer and wine. The carbon
dioxide bubbles make the beer fizz.
We use yeast to make bioenergy in a process called fermentation; this
process converts the sugars which we extracted from inside the straw
into carbon dioxide and ethanol. As each sugar molecule enters the
yeast, it is broken down and the yeast converts the sugars into ethanol
(which is fuel) and carbon dioxide. This takes places in a piece of
equipment called a fermenter.
Did you know?
The ancient Egyptians discovered
yeast and we have learned from their
writings and artwork that they have
been making bread for over 4,000
years.
This is what yeast cells look like under a microscope