Fungi and Food

You’ve probably heard of yeast before and know that we use it to make bread, wine and beer.

But did you know that yeast is a kind of fungus?

Humans have been using yeast to make bread for about 5,000 years. There is evidence of its use in Egyptian hieroglyphics depicting bakeries and breweries. Yeast colonies have also been found in containers that were used to store alcoholic beverages over 4,000 years ago in Israel.

We have used yeast for centuries but couldn’t see them until after the microscope was invented in 1680. Even then we didn’t realise they were alive or that they were responsible for fermentation.

This didn’t stop us from commercialising them though. Yeast was sold in the Netherlands from as early as 1780, with manufacturing moving from a cream/liquid form to solid blocks to the granulated yeast we use today.

Yeast was first described as a fungus in 1837 but the process of fermentation by yeasts was not understood until 1857. In 1888 we worked out that we could culture yeasts, which allowed us to isolate single species and then develop different strains. Today, there are over 1,500 species and over 8,000 strains of yeast all with different properties producing different flavour profiles in their products. There have also been around 600 different compounds identified that can affect flavour and aroma - some yeasts can even produce flavours such as banana, cherries or maple syrup!

Yeasts are special little fungus; they are single celled organisms which look more like bacteria than a typical fungus. They reproduce by ‘budding’ where a small bud, also called a bleb, is formed and grows and eventually splits off from the ‘mother’. Yeast can also grow really fast. A single cell can grow a visible colony of up to a million cells within 48hrs.

In addition to beer, wine and bread, we also use yeasts for non-alcoholic beverages like Kombucha and root beer, as nutritional supplements and probiotics, and for our national spread – Vegemite!

At the NSW DPI Plant Pathology & Mycology Herbarium, our mycologists have been preserving specimens of fungi since the 1960s. While the herbarium focuses on plant pathogens, it also holds extensive collections of non-pathogenic and beneficial fungi, including yeasts. The herbarium also offers preservation of cultures as a commercial service and has been working with local agribusinesses to assist with preservation and vouchering of their yeast strains.