Our guest this week is Sydney Porter, head brewer at Southern Yankee Beer Company in North Houston. We talk about the differences between ales and lagers and the origins of each, and taste some of her offerings. Look for Southern Yankee at the For The Love of Craft Beer Festival on May 18 at Thistle Draftshop in Spring, or swing by and check out the brewery for yourself.

Find Southern Yankee below

Ales vs. Lagers

A Story of Top vs. Bottom and Cold vs. Warm Fermentation

History, Mutations of Yeast

For the average beer drinker, the difference between an ale and a lager comes down to how the beer looks, smells, and tastes. Ales tend to be fruity-estery, while lagers are clean-tasting and frequently described as “crisp.” But to a brewer, the difference is more fundamental than that.

Simply put, lagers use an entirely different type of yeast during fermentation. All of the knock-on effects — from different flavors and aromas to decreased fermentation temperatures — arise from this difference.

So, the difference is in the strain of yeast. One ferments at a warm-ish temp (ales), and the other (lagers) at a cold temperature. This is also the same at the difference between “top-fermenting” (ale) vs. “bottom-fermenting” (lager). This simply explains where the yeast sediment settles. One at the bottom of a tank, the other at the top. While it’s not important to know this information, it is occasionally thrown about in conversation, so it’s one more piece of info to be armed with when entering a beer nerd convo.

All of this comes down to the difference between the wild and naturally occurring “ale yeast” or S. cerevisiae and the mutant that immerged that was eventually isolated and called S. pastorianus.

A cool thing mentioned in the article is that there is no “wild” version of lager yeast in Europe. It needs to be propagated by humans.

“Lagers are relatively new to the brewing scene. They first arose in Bavarian breweries in the late 15th or early 16th century, then eventually spread to the rest of Europe, and eventually to the rest of the world.”

This was a good note, and something I’ll talk about a little bit further in a second, but “All of those beers you think of as “national” brands — Heineken, Tsing Tao, Sapporo, Kingfisher, Budweiser to name just a few — those are all lagers. Lager yeast, Saccharomyces pastorianus, was first isolated and described in 1904 by the Danish mycologist Emil Christian Hansen while working at the Carlsberg brewery in Denmark.”

“But what of lager yeast? it became clear that S. pastorianus — lager yeast — is a hybrid of S. cerevisiae (ale yeast/wild yeast) and S. eubayanus (the Peruvian/Argentinian yeast) (this was later discovered to be the other yeast strain that created the new lager mutation instead of the ale yeast slowly adapting to its environment like first believed.

“But where did this new yeast really come from? The concept of slow mutation didn’t quite work because the strain made a relatively sudden appearance. It had been known that Cerevisiae was one parent strain of Pastorianus, but what was the other one? No one was really sure – until recently, that is. A study published in the journal Proceedings of the National Academy of Sciences of the United States of America on August 22, 2011 identifies the other parent strain of Pastorianus as Saccharomyces Eubayanus. Eubayanus is native to, of all places, the Patagonia region of Argentina.”


Basically, two sets of lager yeast chromosomes are from ale yeast, and two are from this wild Patagonian species. The Patagonian species is what gives lager yeast its interesting cold-tolerant and sulfite-metabolizing characteristics that manifest in the distinctive flavor and character of lager beer. Lager beer is fermented and then “lagered” (stored) in caves for a period of weeks or months at temperatures hovering in the 40s Fahrenheit. This low-and-slow fermentation means that lagers taste “clean” and lack the fruity esters characteristic of ales.

How did this Peruvian Yeast bond with a wild European One?

“The discovery of the New World and the establishment of trans-Atlantic trade happened at the same time. While nobody actually knows how S. eubayanus got to Europe — it could have hitched a ride on a fruit fly or a piece of wood — then eventually ended up in the cold-fermenting vats of Bavarian beers. There, S. eubayanus fused with S. cerevisiae to form a hybrid strain, which then evolved in the brewing environment by dropping some genes here and there — the cold and high-alcohol environment of a brewing vat made sure to kill off any unfit mutants — to the new brewing strain S. pastorianus: the modern lager yeast. Which then, via trade or early corporate espionage, traveled to breweries across continental Europe and beyond. And, like ale yeast, each time S. pastorianus arrived at a new brewery, it quickly adapted to its environment, forming the various lager strains available today.”


There have been studies of the history of the “Columbian Exchange,” whereby Europeans brought disease, religion, slavery, alcohol, and colonialism to the new world in exchange for treasure, tobacco, cocaine, maize, and potatoes, among other things. The timeline for S. eubaynus to hitch a ride back across the Atlantic in the mid-1500s to get friendly with Cerevasiae fits, and as with other exchanges, the Europeans got the better part of the bargain.”

Lagers were originally still fairly dark. It wasn’t until the mid-19th century that they got paler and became the lager we know today, though dark lagers do still exist.

About Yeast

Now we know how the yeasts came to be, let’s talk about what they do for the beer with a little more depth. Connecting the dots from the last episode, was fun for me as I researched this. We discussed esters and phenols in the IBU episode, and this is where we can see a connection in what chemical reactions produce what flavors, and where that all comes from… i.e. yeast and fermentation.

None of this is to say that there are only two yeasts. These are just the two parent strains. There are lots of yeast strains within these two parents used for beer.

“Em Sauter, an Advanced Cicerone and the founder of Pints & Panels, offers an easy analogy: She tells me to imagine yeast as pets. Say ale yeast is a dog and lager yeast is a cat. Sure, they both have two eyes, four legs, and fur, but they behave remarkably differently. And even within the cat category, you have plenty of variation—tabbies, black, Siamese, Persian, Maine Coon—that also have their own personalities.”

Kate Bernot

For the most part, ales have more yeast-derived aromas and flavors than lagers do. Ales might be spicy and fruity just from the yeast alone—without any spice or fruit added—while lagers are in general clean and neutral when it comes to the yeast’s influence. Where do ales’ yeast aromas and flavors come from? Esters and phenols, two by-products of fermentation. Esters typically give off fruity-floral notes: banana, pear, apple, rose. Imagine a hefeweizen and its beautiful banana aroma. Those are from the yeast esters. Phenols are a different type of compound, and they creates clove-like or peppery notes. Imagine a complex Belgian saison or tripel and its spicy aroma: Those are phenols. Ale yeasts produce both esters and phenols to some degree, which is why ales have a more noticeable yeast profile than lagers

“That’s not to say lager yeast doesn’t produce flavor compounds at all: It does. But brewers have learned that the yeast itself will clean up or reabsorb those flavors and aromas if left to rest for a period of time. (Lager means “storage” in German.)” The fermentation will produce esters and and diacetyl (buttery flavor), so in order to get rid of them, the beer is left to “rest” or ferment longer. And the yeast continues its feast and “cleans up” those excess chemical bi-products of the initial fermentation.

Lagers in the US and their importance

Lagers are the most well-known beers in the US, and while that’s changing thanks to craft beer, it’s with good reason.

The history of lager in the US is interesting. For a long time it was the primary style available and is ubiquitous in the “big beer” industry. There is good reason for this. Germans were one of the largest and most successful immigrant groups in the US, beginning many businesses and industries including brewing. Their success allowed them to build infrastructure and technology specifically designed for lager brewing and transportation. Economies of scale and all that later, and you have it being the most widely brewed and established “US beer.”

Bob Brewer

Lager is ostensibly harder to brew. It requires longer fermentation times, and more precise temperatures.

Ale is much easier to produce than lager in that it takes a lot less time. Time is money after all. Ale can also be quite forgiving in other ways since the traditionally stronger flavors and higher hop rates can mask otherwise heavy-handed brewing. Lager brewing takes a lighter touch, more time, and more attention to detail throughout the entire process, which can be difficult for smaller breweries that are set up to be ale-specific. While ales definitely have their place, lager is becoming an increasingly more important part of the craft lineup, positioned as a style that can attract a greater number of consumers, which allows smaller brewers to better compete with mega-breweries.

Episode 3 – Ales & Lagers at Southern Yankee Beer Company
Resources used in this episode
What is the Difference Between a Lager and and Ale?
Ask Kate About Beer: What’s the difference between ales and lagers?
Lager: The Most Popular Beer on the Planet
The History of Lager in America
Wikipedia: Ale
Wikipedia: History of Beer

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