John Kimmich, the mastermind behind The Alchemist brewery and Heady Topper double IPA has little interest in joining discussions about hypothetical differences between IPAs or Double IPAs brewed on the East Coast and the West Coast. “I’ve got to say, I think that [East vs. West] is outdated at this point.” However, the “best IPA” debate does provide context for something more relevant—the effect that yeast selection has on hops aroma and flavor, particularly when it comes to the new “impact” or “flavor” hops.
Kimmich acquired the Alchemist house yeast strain, known as “Conan” as well as VPB1188, when he worked at Vermont Pub and Brewery. Over time it evolved into his own, just as Vermont Pub and Brewery founder Greg Noonan made it his own after acquiring it from English sources. Kimmich particularly likes the apricot and tropical fruit aromas that this strain produces, a combination of the esters that result after yeast creates alcohol and the hops-derived aroma compounds that evolve during the fermentation process (called biotransformations by brewing scientists).