Part 2-Yeast

Moving to the subject of yeast.

Yeast, a single cell organism, is used to turn the various sugars in malted grain/wort into alcohol. The importance of yeast research is illustrated by also looking at the wine industry.  As an example, in 2019 a university in Spain claimed to have developed a yeast strain that could impart the same taste and aroma as aging wine in an oak barrel. This points out the flexibilities yeast brings to the table relative to fermenting. Imagine a microscopic cell has this much influence on making alcohol, CO2, the myriad flavor and aroma options and mouthfeel in beer.

“Yeast can also take credit for the classification of the beer styles. Brew masters pick a yeast according to the recipe or the style of beer they want to make. Yeast is identified as either an ale yeast or a lager yeast,” according to Beer Cartel blog.

Yeast is a complex ingredient in beer. There are hundreds of yeast strains used in beer and each one offers its own personality and characteristics. Some are specifically suited to consume select sugars in the wort and some have stronger endurance to perform that task.

Today there are many manufacturers of pure brewer’s yeast strains. It is important to realize yeast also occurs naturally in the environment and wild yeast in not necessarily good in brewing. For this reason, early brewers had real problems controlling consistency of the performance of their yeast.  Yeast is added after the wort boils (with the hops) and after the wort has cooled (temps are dictated by style). Yeast is so important that some brewers are very secretive about the yeast variety they use.

Yeast bought for home brewing is often sold by the number of cells in a vial or package. For example, a small bag of a pure yeast strain will contain 100 million cells and that would generally be enough for 5 gallons of a finished beer. Retail cost is about $10.00.

Dr. Linda Bisson has spent much of her life doing research on yeast. Dr. Bisson say there are thousands of yeast strains and many strains are naturally occurring in the wild. Mentioned previously, the big contributor to mouthfeel is the way specific yeasts react with specific sugars in the wort- specifically dextrin sugars.

People have asked if bread or wine yeast can be used in beer fermentation. The short answer is no, at least not practically. However, a more educated answer is from Mr. Denny Conn, “You can use any kind of yeast to ferment a beer, but the problem lies in the results. Wine/champagne yeast ferments different group of sugars. (The subject of sugars is a complex subject when it comes to yeasts consuming the sugars in wort.) Wine yeast does not ferment malt triose, one of the main sugars in beer wort. The result is that you’re left with beer that doesn’t quite taste like beer.”

“Hops tend to get all the glamor and attention these days, I strongly believe that the real stars of the show—what makes beer fascinating, delicious, and perhaps even nutritious, is yeast,” says Joseph Lavoie-Beer Craftr (sic).  Lavoie explains that before Louis Pasteur’s work in yeast research in the mid 1800’s, brewers knew they had to use the leftover sediment from the previous brew to make the next batch, they just did not know it was yeast that made beer concoction come to life.

According to “Beer Magazine”, different strains of yeast behave differently, so that makes it possible to divide the world of beer according to the yeast. Sixty or more defined beer styles can all be sorted by their yeast into two broad families: the ale family of yeasts and the lager family-top fermenting (cooler temps) and bottom fermenters (warmer fermenting temps) respectively.

To illustrate just how complex the selection of yeast has become, I went to a large manufacturer of brewer’s yeast and counted their yeast offerings for making a few popular styles.  Here is what I found: American Ale-32 varieties; British Ales-45; Belgian Sour Ales-26 and IPA-36.

Here is a sample profile they offer to help in selecting a yeast.


  • Type:Liquid
  • Flocculation:Low/Med
  • Attenuation:73-77%
  • Temperature:60-72°F, 15-22°C
  • Flavor:Exceptionally clean, crisp flavor characteristics with low fruitiness and mild ester production. A very versatile yeast for styles that desire dominant malt and hop character. This strain makes a wonderful “House” strain. Mild citrus notes develop with cooler 60-66°F (15-19ºC) fermentations. Normally requires filtration for bright beers.

 Because wort sugars are ready-made for yeast, one of the complexities of brewing is understanding the myriad types of sugars and their chemical structure. Wort is what gives yeast a foundation to bring beer into its own. The subject of the relationship of sugars and yeast is extraordinarily complex.

Noted earlier, yeast also contributes to beer’s flavors and aromas. It also can aid in making beer clear through the process of flocculation. In flocculation yeast cells form together and settle/drop out leaving beer clearer. Further, yeast can highlight the maltiness and aroma profiles while adding to fruitiness that hops imparts. Yeast will also impact sweetness or dry sensation and mouthfeel in the finish.  Mouthfeel is a huge sensory queue in appreciating a fine beer.

Because yeast and hops do similar things relative to flavor and aroma it is important to understand how each variety of hops and yeasts will impact a style. If you really want to fully enjoy the experience in consuming a fine beer it is helpful to at least understand some of the science.

In the 1880’s a scientist isolated a pure strain of yeast that was suitable for lager brewing, as opposed to ales. This is an example why research is always moving ahead in yeast development.  Even the miners of the California Gold Rush era recognized the special characteristics of a bread made by a bakery in San Francisco. The Boudin family made a special sourdough bread using a special yeast the family discovered.

Beer is unique unto itself because craft beer can and is being produced for regional and national markets. The beers we enjoy today with new flavors and aromas are due to the creativity in beer making  processes and ingredients. New styles have brought beer into new social settings.  Think about seeing beer as a center piece at food pairings, even fine dining establishments, and celebratory gatherings.

Mr. Koch of the Boston Beer Company has made a beer that he says will stand up to any champagne. “Champagne taste with a beer budget? Thankfully, these days, you don’t have to shell out hundreds of dollars to sip that sweet sparkling wine – in fact, you can have the same champagne taste and mouthfeel in your favorite type of beer,” says Kaitlyn McInnis-Editor, Ask Men.

“Thanks to the rise in craft beer, more and more breweries are experimenting with funkier ingredients and brewing methods, including using champagne yeast in their brews! This out-of-the box brewing results in the same umami-packed taste you love in champagne but for a fraction of the cost,” says McInnis.

 Different Beers, Different Strokes for All the Folks!