Yeast is made up of just one cell, and is part of the group called fungi, which contains molds. As Fungi they are part of the other fungi family that we all recognize including mushrooms that we eat, molds that help mature blue cheese, also the yeast used for baking to leaven bread and even the process of making medicines like antibiotics.
Although there are many different types of yeast the one we would all be most familiar with is the yeast used in baking and brewing, this type is called Saccharomyces cerevisiae, saccharo” meaning sugar and “myces” meaning fungus. This particular type of yeast is very strong and helps fermentation which is the process in which to make bread dough rise.
The main ingredient to make yeast grow is sugar and from this they produce alcohol and carbon dioxide. This reaction with the sugar is very important in food production. In beer yeast is a very important ingredient to the alcohol fermentation and the carbon dioxide for the brim. When baking bread the fermentable sugars present in the dough are converted into carbon dioxide and alcohol but during the baking process the alcohol evaporates. The carbon Dioxide gas cannot be released which as a result the dough rises.
In the industry the yeast is grown in a very controlled environment with in big tanks containing sugary water with the presence of oxygen. When there is enough yeast the liquid is pumped out and dried.
Yeast can also be found in nature, mainly in fruits that have fallen off trees. This is because the fruits are rotten and through the activity of mould and the natural sugars in the fruit this reaction forms alcohol and carbon dioxide. There have been articles written about drunk animals that have eaten these fallen and rotten fruits.
The yeast used in the food industry is reproduced by a process called budding. This is a process where within each cell wall a new bud grows, this bud eventually breaks away to form its own cell, each cell approximately reproduces 12 – 15 times. To get an idea of how small these cells are, they are comparable to the size of human red blood cells and 30 billion yeast cells make up just one gram of bakers yeast.
The budding procedure means that they can be seen through a microscope and they appear in 8 shaped forms. Mazurek Optical Services can use their biological microscopes in order to see these tiny yeast cells.
