Yeast: A Force Behind IPA 2.0

Today’s most creative craft brewers know how to select yeast strains that don’t just ferment maltose, but also dance alongside hops that are at once tropical, citrusy, earthy, piney, and floral.

Dave Carpenter Jun 2, 2017 - 9 min read

Yeast: A Force Behind IPA 2.0 Primary Image

Conan. Pacman. Chico. Denny’s Favorite. These are not, as the uninitiated might initially suspect, terms for the Mountain Time Zone’s most popular cannabis products. These are, in fact, names that have been lovingly bestowed upon distinct strains of Saccharomyces cerevisiae: good ol’ ale yeast.

Just as poodles and Great Danes reflect the selective pressures that breeders have placed upon Canis lupus familiaris, individual yeast strains express the cumulative effects of centuries of environmental adaptation and random mutation. Beer nerds sometimes describe certain styles as “yeast-driven,” meaning that yeast expression is a critical aspect of the finished product. English bitters, Hefeweizen, and most Belgian-inspired styles find themselves huddling beneath this umbrella.

Brewers of such styles will get into heated debates about the relative merits of yeasts from Westmalle or Chimay, Dupont or Thiriez, Weihenstephan or Schneider. Brewers of American India pale ale, however, have long specified a crescendo of exceptionally precise hops additions, only to close with a predictable denouement: “Ferment with American ale yeast.”

Admittedly, we know what that means (more on that in a minute), but American IPA ain’t what it used to be. Today’s most creative craft brewers know how to select yeast strains that don’t just ferment maltose, but also dance alongside hops that are at once tropical, citrusy, earthy, piney, and floral. The trick is knowing what you want and then experimenting until you get it.


And knowing what you want from your yeast is a major driving force behind IPA 2.0.

Châteaux de Chico

There are plenty of American-ale yeasts out there. But just as we use Q-Tip and Kleenex to identify cotton swabs and facial tissues of any brand, talking about “American-ale yeast” means only one thing: Chico.

Chico is probably the most widely used craft yeast strain on the West Coast, if not in the entire country. You know it as White Labs California Ale (WLP001), Wyeast American Ale (1056), or Safale US-05. “Chico” refers to the hometown of Sierra Nevada Brewing Company, from which the strain is said to have been sourced. Legend has it that Sierra Nevada, in turn, obtained it from Ballantine decades ago. Whence it arrived at Ballantine may forever remain locked in the vaults of brewing lore.

Whatever its roots (and inevitable mutations along the way), Chico is famously clean, meaning that fermentation by-products are relatively few. Thus, the West Coast IPA drinker experiences a more or less unadulterated expression of malt and hops. But despite Chico’s clean reputation, it can, in fact, throw impressive esters when it ferments above or below its preferred temperature range.


“These [West Coast] yeasts have a potential ester profile. If you play with fermentation temperature, you can really influence the character of the beer,” says Richard Norgrove of Bear Republic Brewing Company (Healdsburg, California). He’s partial to White Labs WLP051 California Ale V, which is somewhat more expressive than classic Chico yeast (“Hmm, where did that guy get that number?” asks the award-winning brewer of Racer 5 with a chuckle upon mentioning Cali V).

“If you ferment California Ale V at 66–68°F [19–20°C], say, it’s not going to throw tremendous esters. But raise it to 72–74°F [22–24°C], and that same yeast can throw bubblegum and Juicy Fruit character into the beer, giving a round sweetness that complements the hops profile.”

Norgrove knows a thing or two about integrating interesting flavors. While Racer 5 remains a classic interpretation of the West Coast IPA style, Bear Republic’s Apex imperial IPA is a chance to play. “We reserve the right to change Apex each year according to the hops that are available,” he tells me. Right now, his favorite hops is a new cultivar known only as Experimental Hop 06277. He has nicknamed it Stitch for its ability to seamlessly weave in and out of Apex’s hops profile and keep beer drinkers guessing. And it seems to work well with the brewery’s house yeast strain.

Because Bear Republic’s beers are bottle conditioned, the interaction between yeast character and hops profile changes with time. “Everyone at Bear Republic has a favorite way to drink Racer 5,” he says. For Norgrove, that’s three to four months after production. “The hops no longer dominate, and you start to get some esterification. It becomes almost more English in style.”


Hmmm! A West Coast IPA that tastes English?

English Accents

Erik Jensen of Green Flash Brewing Company in San Diego thinks a key differentiator for East and West Coast brewers of IPA may be the lineage of their preferred yeast strains. Green Flash’s proximity to White Labs affords him the opportunity to taste a number of the yeast bank’s experiments, which often include splitting a single batch of wort and fermenting it with multiple yeast strains. Each resulting beer gets tested for a number of key metrics, including International Bittering Units (IBUs).

“A beer that hits 50 IBUs with a California-ale strain might only come up as 35 IBUs when fermented using a British-ale strain, even though the original wort is the same,” says Jensen.

It seems that the house strains that have developed at East Coast breweries may enjoy a more direct lineage to classic British strains than those on the West Coast. The Alchemist’s well-known Conan strain, for example, was begat from one of brewing legend Greg Noonan’s preferred yeasts at the Vermont Pub and Brewery. In all likelihood, Noonan’s strain had its origins in the United Kingdom, but as with Chico, Conan’s actual family tree may very well be lost to the ages.


Whatever the case may be, it’s undeniable that many of the best IPAs from the East Coast exhibit a qualitatively different bitterness and hops presence than their West Coast counterparts. Neither is innately better or worse than the other. Rather, they represent two different approaches to the same overarching style (see “Gather No Moss—Inside The Alchemist’s Heady Topper” for more insight into the yeast-hops interaction).

Sixty miles south of The Alchemist, Dan Foley of Foley Brothers Brewing (Brandon, Vermont) admits to using not just one yeast strain but a blend. “The yeast strain absolutely has a big impact,” he says. “We pitch a ton of yeast with lots of oxygen so that our IPAs ferment out in just three or four days.”

Foley believes in getting his IPAs from grain to glass as quickly as possible. That means fast fermentation and quick conditioning. The Foley brothers like to ferment their IPAs in the high sixties Fahrenheit (about 20°C) and then raise the temperature to the low seventies (about 22°C) near the end of fermentation to assure full attenuation. “Our dry-hop regimen is also fast,” Foley observes. “We’ll do a single dry hop for standard IPA and a double addition for double IPA.”

Foley also advises brewers to keg their beer if at all possible. “We started out by bottle conditioning, and the warm carbonation period seemed to age the beer and degrade the hops profile.” Kegging lets him keep the beer cold, which is crucial for preserving delicate hops flavors and aromas.

East Coast and West Coast brewers are both fanatical about freshness, which means that in the end, we all win, no matter the yeast strain.

A Yeast for the Senses

There’s no right or wrong way to brew IPA, as long as consumers continue to enjoy the products that today’s brewers are so carefully crafting. Yeast selection certainly makes a difference, but even the perfect strain won’t deliver if it’s treated poorly. But given the right combination of oxygen, pitch rates, fermentation temperature, and, yes, yeast strain, the dedicated IPA brewer can turn out a work of art. And that’s something we can all get behind, no matter where we live.

From sanitation and inoculation to propagation and fermentation, Craft Beer & Brewing Magazine®’s Yeast Lab DVD has everything you need to build a healthy population of yeast and make the best beer possible. Get your copy today!