Over the past few years, cold IPA has introduced many brewers and drinkers to the idea of a non-lager beer style fermented with lager yeast. However, this is a familiar move that brewers have been using ever since lager yeast strains and bottom-fermentation techniques first spread from Bavaria in the 19th century. Whether for reasons of practicality or flavor profile, many styles commonly brewed with ale yeast have also been brewed with lager yeast by breweries all over the world.
Lager brewing took the world by storm starting in the mid-1800s, as the popularity of the golden pilseners from Bohemia spread, and as German brewers emigrated to other countries in search of new opportunities. With them they brought lager yeast (Saccharomyces pastorianus), a genetic hybrid of ale yeast (Saccharomyces cerevisiae) and the more cold-tolerant Saccharomyces eubayanus. This genetic hybrid—lager yeast—evolved via adaptation over the centuries in Bavaria to ferment at cooler temperatures and produce crisp, clear beers. That was in stark contrast to the relatively murky, tart, and/or funky ales that were ubiquitous in other brewing regions.
An Old Trick, Style by Style
As lager brewing became more popular, ale and porter brewers reacted to the new competition with beers such as cream ales—essentially, pale lagers made with ale yeast. That brings us to an example of where things got mixed up: Once this style became established with consumers, some brewers began making them by blending beers made with ale and lager yeast. Others who were used to brewing lagers also wanted in on this trendy style—so they simply brewed it with lager yeast.
Porter was a popular style in most of the Anglosphere and trade-connected countries going all the way back to the 18th century. In many regions, including Eastern Europe and the United States, brewers who switched to lager yeast and bottom fermentation kept making their porters that way without much fanfare. Until Anchor resurrected English-style porter in the 1970s, most American porters were brewed this way. Arguably, they had more in common with the porters of the Baltic countries, Poland, and Russia—beers that we now know as Baltic porters—than with the top-fermented examples hanging on by a thread in their British homeland. That tradition of bottom-fermented porters lives on in beers such as Yuengling Dark Brewed Porter and many Baltic porters.
Nor has the stout family escaped lager yeast. Tropical stouts have adapted to bottom fermentation, with Jamaica’s Dragon Stout, Sri Lanka’s Lion Stout, and the Caribbean- and Nigerian-brewed examples of Guinness Foreign Extra Stout as some prominent examples.
Even traditional farmhouse beers have fallen under the sway of lager yeast—namely, French bière de garde. Some of those brewers use lager yeast, some use ale yeast, and good luck finding out who uses which without asking them personally.
Meanwhile, Dutch and Belgian bok beers developed the other way, taking a German lager style (bock) and using whichever yeast made the most sense. You know you’re getting a somewhat strong, malty, amber-red beer, but fermentation method varies with little indication offered to the drinker.
Steam beer is a quirky example of pragmatic brewers using the yeast they had within the constraints of their environment to make beers the market demanded. For whatever reason, this unique name stuck with brewers in the San Francisco Bay Area in the mid- to late 19th century, as they brewed with lager yeast at ambient temperatures in shallow, open-fermentation pans. The style nearly died out as refrigeration made colder fermentation possible, but the idea of steam beer lived on because of one Fritz Maytag, who bought the struggling Anchor Brewing in the late ’60s. Over the next few years, Maytag re-tooled the Steam recipe from a pale lager–like adjunct beer into something more closely resembling an English pale ale. The malt combo of two-row pale and crystal 40 would go on to set the baseline for American pale ales and IPAs well into the next century. Likewise, the selection of English Northern Brewer hops provided a bitterness that set Steam apart from the light lagers of the day, and that assertive profile would become the norm in the coming microbrewing movement.
Back to Cold IPA…
The basic approach of steam beer is essentially what’s driving the current cold IPA trend: Certain lager yeasts are perfectly happy getting up into the lower temperature range of ale fermentation—usually around 60–65°F (16–18°C)—and they still produce clean beers lacking the fruity esters apparent in most ale fermentations. They also still produce small amounts of sulfur dioxide, the antioxidant compound that gets some credit for the flavor stability of lagers. This all allows for crisp beers that have good shelf stability, can be produced within ale-like timeframes, and happen to be great for showcasing hop aromatics.
As a practical matter, this also means that lager breweries can expand their range into ale styles without bringing in a new yeast strain—and that ale brewers with expressive house yeasts can play around with more neutral fermentation profiles.
As a push-back to these developments, I’ve heard some bemoan the debasement of style definitions. “You can’t call it an ale if it’s brewed with lager yeast,” is a common retort.
So, what is it that makes a beer an ale or a lager? Given the historical context, this question strikes me as more philosophical than technical. My feeling is that the modern approach to defining beers based on the type of yeast used is too narrow of a view. However, the discussion will no doubt continue, and further exploration of the topic could surely fill many more pages.
As the beer world rediscovers the old ways of brewing non-lager styles with lager yeast, where will we go next? Plenty of breweries are already brewing (non-cold) hazy and West Coast IPAs with lager yeast, including our own Hopnosis IPA at Firestone Walker. Moving past the IPA space, tropical stouts, Baltic porters, and bières de garde have already shown us that malt-focused beers can be equally delicious using this method.
I, for one, welcome more experimentation in this area—and I can’t wait to see what my fellow brewers come up with next.