Beer is made through many ingredients and processes, all ending up with the delicious golden drink you know and love.
Yeast is a key one of these ingredients, but often gets ignored in place of other ones like hops or malt.
In fact, beer making has gone on for thousands of years, yet most of that time was without the magical help of yeast.
As scientists have examined and tested the brewing process over the centuries to make it more efficient, they’ve discovered better ways to do things – and yeast was one of them.
But what is it?
Well, we’re going to tell you about it today, breaking down what it is and what makes it so great.
Additionally, we’ll look at the different types of yeast, as well as the various ale strains you can get – and brew with!
This article will be particularly useful to those of you who want to get into homebrewing your own beers.
What Is Yeast?
Yeast is a microorganism, which is basically a really small, living thing.
It’s incredibly important because it is responsible for the fermentation that makes the final beer, turning it from the “wort” liquid into the delicious end product.
But how does it do this? The yeast metabolizes the sugars that have come from grains.
Metabolize essentially means using a chemical process to turn something into something else.
In the case of brewing, the something else that it makes is alcohol and carbon dioxide, which turn the wort liquid into beer.
Yeast’s influence isn’t just scientific, though, as important as it is. The microorganism also helps to give the beer its character and flavor.
Types Of Yeast
There are two main types of yeast that are used when brewing beer.
The fermentation power that yeast has is heavily influenced by temperature, and different types of yeast ferment at different ranges of temperature.
The two key types are Ale Yeast and Lager Yeast, and we’ll get to those in a minute.
These two variations are known as Domesticated Yeasts, which has its name because the microorganisms are bred specially for their beer-making characteristics.
It hasn’t always been how things were done, though, with the first case of domesticated yeasts being in the 16th century.
In fact, yeast domestication has been studied not just in beer, but cheese and wine too.
It all helps to build a better scientific picture for brewers. So, for almost 500 years we’ve been benefiting from these special types, which are…
Ale Yeast – A Top-Fermenting Yeast
Ale yeasts are one of the types of domesticated yeast. It’s a favorite for brewers because it ferments at a good temperature range of 10 to 25°C.
This is a favorable range for brewers because it’s quite typical for how we usually exist, and it can be kept through air conditioning or heating systems, depending on whether it needs to be hotter or colder.
In fact, a lot of the yeast strains ferment at 18 to 22°C.
The Ale type of yeast is also known as a “Top-Fermenting” variation. It has this name for very literal and simple reasons: when fermenting, ale yeasts rise up to the top of the fermenter device.
These types of yeast are used to brew a good variety of popular beers: ales (unsurprisingly), porters, stouts, and wheat beers, as well as altbier and köilsch (which are both German).
Lager Yeast – A Bottom-Fermenting Yeast
Lager yeasts are the other main type used for brewing, and operate in an opposite way to Ale yeasts.
Lager strains prefer colder temperatures for their fermenting, working best in a range as low as 7 to 15°C.
This has its differences, the chilly temperatures stop extra things being produced when brewing, such as chemical products or off-flavors (essentially tainted tastes).
This seems quite a benefit! Most of us wouldn’t work our best when that cold, we’d grab a sweater, but lager yeast does very well operating in such a cold climate.
It’s opposite to Ale yeasts in another way, too, known as a “Bottom-Fermenting” yeast instead.
Lager yeasts don’t rise up to the top of the fermenter when fermenting, rather sink down a bit and work their magic at a lower level.
These types of yeast are used to brew a different variety of popular beers: lagers (unsurprisingly again!), bocks, and pilsners, as well as märzen and dortmunders (both German, again!).
As we’ve mentioned, yeast brings character and flavor to beer during brewing, as well as being responsible for its transition from wort to beer.
Well, yeast has a great many other qualities to it, which a brewer may want to keep in mind when choosing what yeast type and strain to use for their production.
Below, we’ve broken down a few of its features.
A flavor profile is the combination of flavors that make up a food dish or drink. Each strain of yeast brings its own complex profile of flavors, each contributing a difference to the taste of the final product.
Depending on what you want the end brew to taste of, you’ll want to pick your strain carefully. Like something dry at the end, like a Brut IPA?
Choose a yeast strain to match. Want something malty, like an Oktoberfest beer? Use a Munich or Vienna yeast strain (keep reading for the different types!).
Different strains will bring out different flavors, like hoppiness or fruitiness, and you need to find the one right for you.
Don’t be put off by the weird word, this just refers to how the microorganism yeast cells group together, which makes a larger gang that is easier to chemically separate.
If the flocculation rate is high, the cells should come apart quicker and the beer should become clearer sooner.
Since brewing is a science, you need to get the details right.
Imagine if you were trying to make something in a science lab, with test tubes and measurements – you’d have to get them all right to get the correct outcome.
Beer is no different! Whatever strain you end up choosing, you need to make sure you ferment it at the correct temperature.
Too low or too hot and the strain may not ferment properly.
Another interesting term, this is a crucial aspect to successful brewing.
It’s essentially a measure of how much the yeast strain is going to ferment the sugars that are in the wort, turning it into the final beer.
Whichever strain you pick, you need to make sure that you’re applying the correct attenuation.
This tends to be split into suggested categories, with anything above 78% being the top end, the medium being between 72% and 77%, and the low end theory being anything less than 72%.
If you follow these suggestions, and research the best attenuation for your chosen strain, your beer should come out tasting correct.
But what type will you pick? We’ve assembled a list of the broad categories of strains, which all have various yeasts you can buy within them.
If you like the general characteristics, you can pick one of the many.
With a medium flocculation and attenuation, this is a sturdy type of yeast that should be easy to work with.
If the brewing is done correctly, it should give you a clean character, with a reliable flavor and appearance.
American Ale yeast can also endure low temperatures too, acting more like a lager yeast, but it’s probably wise to keep them higher.
Some examples of American Ale yeast would be Wyeast Denny’s Favorite 50 1450, which offers a malty and fruity final beer.
Another popular one is the Fermentis Safbrew T-58. It may sound like a type of Terminator, but it actually offers a spicy flavor in the end beverage.
Famous for their fruitiness, these yeast strains produce pleasant aromas such as allspice and peppercorns.
Its alcohol tolerance is medium to high, a grade measured by %ABV that will tell what strengths of alcohol your yeast strain cells will be able to ferment in.
An example of a Belgian Ale yeast is the East Coast yeast Trappist Ale ECY13, which gives a lovely dry and fruity taste.
Belgian Lambic / Sour Ale
These can be quite tart, but rewarding. If you can get past the sourness, you may want to brew a kriek or a faro ale.
An example of one of these more sour yeasts would be East Coast Yeast Brett Anomala ECY04, which gives a sharp and funky flavor.
These can bring a whole range of flavors. Some will give you something fruity, while a London yeast is likely to give you something lower and more wood-like.
Some examples of yeasts would be Coopers Pure Brewers’ Yeast (for a nice and round flavor), and Mangrove Jack British Ale yeast for something a touch spicier.
India Pale Ales
Hopping across the ocean, you may know these by their acronym: IPA.
There are so many different types of these. I know my friend and I used to enjoy a particularly strong and fruity one in the past.
These tend to get character from hops, or citrus and fruity flavors.
An example of a yeast strain would be the White Labs Whitbread Ale WLP017, which brings exactly one of those fruity flavors and has a low end attenuation.
As you now know, Yeast plays an incredibly important part when brewing beer. It couldn’t ferment without it!
But it also gives it many of the flavors and characteristics that make each beer stand out.
If you’re trying to homebrew your own, you now have an understanding of the many different types of yeast, as well as their various strains and characteristics!