Yeast is a single-celled microorganism that belongs to the fungi family. Scientifically, they are called Saccharomyces cerevisiae, which stands for sugar-eating fungus. Like all other microorganisms, they are minute, and can only be observed under a microscope. Each cell is shaped like an egg. One gram of yeast consists of approximately twenty billion yeast cells.
They are widely available spread across different forms and types of vegetation. For thousands of years, yeast has been used as an industrial microorganism. They digest food to obtain energy and grow. They have a sweet-tooth for sugar and are attracted to feeding upon the various forms of sugar available in nature. Let’s take berries as an example here. When they are over-ripe and fall onto the ground, yeast latches themselves onto these berries, and feeds on them, leading to the fermentation of the berries, turning them alcoholic. It should also give you a fair idea of how beers are fermented
One of the most common applications of yeast is in the preparation of bread. When yeast is added to the bread, it ferments the sugar present in the flour to release carbon dioxide. Since the dough is elastic and does not have a lot of pores, it does not allow the gas to escape, and thus holds it in. The accumulation of carbon dioxide over some time inflates the dough which in coordination with the fermentation, makes it softer as well. However, there are a few other applications of yeast as well:
Biofuels - Yeast ferments sugar into ethanol, which is often used as a substitute for diesel in vehicles, and thus used in the production of biofuels.
Probiotics - Vegetarians often use probiotic drinks consisting of yeast as a substitute to compensate for the low vitamins and proteins in their diet.
Drinks - Both alcoholic and non-alcoholic drinks use yeast for various purposes. In the case of non-alcoholic drinks, the yeast is added for flavoring. However, the fermentation is stopped before the rink turns alcoholic. If fermented for longer durations, they react with the sugars and turn the drink alcoholic.
Varieties
There are broadly two types of yeast available:
Brewer’s yeast - This is a wet yeast used for making beer and other alcoholic beverages. It is a rich source of chromium and vitamin B. It also aids in digestion. Additionally, it also helps the body fight certain infections, by producing enzymes in the body.
Baker’s yeast - As the name suggests, this is used for bakery products. It is further broken down into active dry yeast, deactivated yeast, compressed yeast, instant yeast.
Preservation
In most cases, the yeast is packed in small square blocks for home-usage. It is generally refrigerated but can be frozen, and used for up to two years. Yeast is one of the most widely used microorganisms for the production of food and beverages. According to reports, the growth of yeast production has been estimated to grow at a rate of CAGR 9.6%, from USD 3.9 billion in 2020 to 6.1 billion in 2025. It has been targeted for research institutions, raw material suppliers and manufacturers, government bodies, and End-users such as the food and beverage industry.
