A crucial component of beer was created seemingly out of thin air.

Craft beer drinkers are by nature ‘yeast prospectors’; they are always on the lookout for that new or unique flavour in a beer that comes from yeast. Many people have no idea how yeast contributes to the creation of flavour, appearance, and aroma. To a large extent, the yeast contributes to the distinct flavours and aromas that characterise each craft beer. No yeast, no beer, as the saying goes. Wild Yeast, on the other hand, has always been present in nature. This in no way diminishes the significance of barley and hops.

Craft beer’s uniqueness can be summed up in a single word: innovation. Craft brewers aren’t afraid to experiment. The use of ‘prospected’ wild/natural yeasts has helped some brewers carve out a market niche. In this case, these are yeast strains that were found in nature. And are yeast strains collected/harvested from trees, plants, fruits, and other natural sources?

Using wild yeast carries some risk, since a brewer has no control over the final flavour of the beer after fermentation is complete. Yeast exploration and innovation, however, comes with its own set of risks. Researchers, on the other hand, continue to look for new commercially viable yeast in wild yeast. A lot of it boils down to flavour and yeast performance.
First, I’ll mention that beer was first brewed 10,000 years ago using wild yeast. Brewers today have revived this lost art, focusing solely on beer made with wild yeast strains. It all started with a trip around the state of Minnesota to gather wild yeast strains from fruit bushes and trees as well as wildflowers. Naturally fermented beers such as saison, farmhouse, and sour beers use wild yeast to impart their distinctive characteristics.

It’s cool to have something that is both truly local and proprietary, says James Howat, co-founder of the Denver brewery Black Project Spontaneous & Wild Ales. The co-founder of Green Room Brewing, Eric Lumen, says, “Yeast is really a way for a brewery to distinguish themselves.” In spite of the fact that every brewery has access to essentially the same raw materials, wild yeast can impart a distinct flavour to a product.

Wild yeast has been used in new inventions. Lallemand, an innovative yeast manufacturer, announced in June 2020 the development of a new yeast. Wildbrew Philly Sour with a technical designation of GY7b is the name of this new patented yeast. A student of Dr. Matthew Farber, Director of Brewing Sciences at the University of the Sciences of Philadelphia, discovered the strain growing on a Dog Wood tree in a nearby cemetery. A project turned up this particular strain of yeast. In total, there are over 500 different types of beer yeast. The Soft School website claims that there are thousands of different types of emoji.

In the sour beer category, this new yeast has a number of advantages. Despite the fact that this organism is invisible to the naked eye, the discovery has enormous commercial potential.

Now, Philly Sour is being marketed to homebrewers around the world. Because lactic acid is produced by the yeast, there is no longer any need for brewers to introduce bacteria into their sour beer production lines, thus avoiding contamination concerns. Dr. Farber adds, “It’s also delicious.”

The history of sour beer goes back more than a thousand years, but it has only recently become popular. There are, in fact, some brewers who specialise in sour beers.

It has long been known that a single living cell, which is as old as time itself, produces beer. “Beer has been made as a fermented beverage for more than 5,000 years.” That mystery of fermentation was finally solved in the late 1860s after a French scientist named Louis Pasteur isolated yeast cells,” says Eric Abbott, a technical advisor for Lallemand yeast manufacturing. “Before Pasteur’s discovery, brewers accepted that wort somehow started growing a foamy substance that made a delicious beverage. In order to meet the needs of brewers, we are now selling yeast that is tailored to their specific flavour and compatibility requirements.”

So, what exactly is yeast, and why should craft beer drinkers care about it? First and foremost, beer is nothing more than sugar water without yeast. Yeast is a single-celled, living organism that may be small in size, but is nonetheless an organism. It thrives in humid, warm environments with plenty of oxygen and food. The starches in malted grains that are heated in water to release the sugars are the primary source of food for yeast. The myriad sugars in the wort (the product of boiling the malt mixture) react with various yeast strains to produce alcohol and carbon dioxide. Select yeast strains consume the sugars, producing alcohol and carbon dioxide (CO2) while bringing out the best in the hops and malts.

However, how small is a yeast cell in comparison to other organisms, such as bacteria? Homebrewers and larger brewers may need between 5 and 10 grammes of yeast in order to make a batch or test a new recipe. About 150 billion ale yeast cells, or 300 billion lager yeast cells, would be in a 5-gallon pouch of dry yeast. Dry yeast in a 5-gram pouch contains 150 billion cells.