GUIDE TO DIP HOPPING

DIP HOPPING
ORIGINAL & EXPANDED ARTICLE AT BYO MAGAZINE

In 2012 Kirin, the Japanese brewing conglomerate, began talking about “dip hopping,” a technique that its brewers had developed that boosts pleasant hop aromas while suppressing or removing unpleasant off-flavors, like myrcene, and aromas that are derived from fermentation.

The method was used in a number of the brewery’s beers, including the Grand Kirin beers, but received little attention in the larger beer world, especially as a younger generation of brewers were largely focused on giving a never-ending bear hug to the double dry-hopped method.

Van Havig and Ben Love of Gigantic Brewing in Portland, Oregon were visiting key accounts in Tokyo when they stopped by Spring Valley, the craft brewery owned and operated by Kirin. While tasting through some beers, they both were stopped dead in their tracks by “496,” a pale ale that revealed a wonderful hop character. Havig recalls a conversation with a brewer at Spring Valley and asked about the hops used. The answer surprised, delighted, and confused him.

“I said there was no way the hop was Apollo,” recalled Havig. He asked how the flavors were possible through Apollo, and the brewer responded: "Dip hopping".

If the second half of the last decade was dominated by brewers embracing double dry hopping (DDH), there remains the possibility that the future of extracting desired hop flavor in a relatively straightforward way, could be dip hopping.

After being introduced to dip hopping, the brewers of Gigantic slowly started sharing their newfound information with other brewers. Around the same time, the John I. Haas company ran a blurb in its February 2019 newsletter summing up dip hopping this way: “Dip hopping means the addition of hop after wort cooling before (the) start of fermentation.” They note that with this hopping technology Spring Valley “found the following results: 1) Hop enzymes do not contribute to main fermentation, 2) myrcene levels in finished beers are very low, which was found favorable in this case, 3) the production of 2M3MB an onion type of flavor (derived from iso-alpha acid) is suppressed due to a lower H2S content in the beer.”

In 2018, brewers from Kirin presented their findings at an American Society of Brewing Chemists conference that further dove into the science:

“2-Mercapto-3-methyl-1-butanol (2M3MB) imparts an onion-like off-flavor to beer. In a previous study, we purified the precursor of 2M3MB from hops and identified it as 2,3-epoxy-3-methyl-butanal (EMB),” the brewers of Asahi wrote. “We found that during the hot aeration of wort, which has long been considered as the cause of the onion-like off-flavor, the amount of EMB in wort increases with the oxidation of iso-alpha-acids.”

When it comes to dip hopping, just think of it as a different type of steeping or an infusion of hops and wort prior to yeast fermentation or prior to yeast being in the beer.

While the Spring Valley brewers wouldn’t fully reveal their process to Havig and Love at the time, over drinks at Spring Valley, Havig was able to ask a series of questions that gave him the framework for the dip hopping process that has now been passed along to other breweries that have experimented with it in their own ways.

Havig says the current methodology at Gigantic is to use about a half a barrel of hot liquor for every 11 pounds of hops. They sanitize a fermenter, add the hops “and then we’ll just pump the water in there at around 170 °F (77 °C) and let it sit for an hour and then we just knock out on top of it at totally normal temperatures; whatever is normal for whatever we’re brewing.”

So far Gigantic has used this process mostly with ales but did a collaboration lager with Magic Rock in the United Kingdom using the process. Kirin/Spring Valley created dip hopping, but conversations with breweries lead back to Gigantic for introducing it to the United States.

Niko Tonks, of Fair State Brewing Cooperative in Minneapolis says his brewery first made a dip hopped beer as a collaboration with Three Floyds of Munster, Indiana. Jerrod Johnson, of Fair State had worked at Surly with Todd Haug, who is now at Three Floyds. Before that, however Johnson worked with Havig.

See how this works?

Tonks said the beer they made was a success, wonderfully aromatic, a throwback to West Coast IPA, but without some of the pungent onion and garlic aromas. Different from Gigantic’s approach where water is used with the dip hops in the fermenter, Fair State brewers pulled about 10% of the wort from the boil, chilled it down to 170 °F (77 °C), and transferred it to the fermenter to create a hop tea. By the end of the boil the rest of the cooled wort was added about an hour later. While the reported results for Fair State have been positive, the technique is not one that the brewery could do with any regularity.

“Especially not on a large scale because the big downside is just that it renders the yeast from that beer unusable. We’re essentially fermenting on a whole bunch of hop pellets and so it’s just a big morass of goo at the bottom of the tank. When you’re done you can’t really crop it and so for that reason it’s a difficult technique to actually mainstream into your production,” he says.

Hops are loaded into the fermenter prior to running wort or water on top of them to create a hop tea. An hour later, the remaining wort is chilled and added to the fermenter and yeast is pitched as usual.
Though for brewers that are used to DDH ales and pitching a new yeast every brew day — as many homebrewers do — this process might be easier, he notes. Tonks says his brewery is interested in doing more of these beers, but for now, they are best suited for special occasions, like collaborations, given their production schedule.