Get The Scoop On Dip Hopping

Perhaps the most interesting things about dip hopping are the amount of data about the technique along with its relatively low-profile presence in the weird world of brewing hype. Before jumping into process details, let’s check out a timeline of how this method got started and introduced to US craft brewers.In 2012, brewers from Japan’s Kirin Brewing began talking about a technique that boosts pleasant hop aromas while suppressing off-flavors. During a trip to Japan in 2014, Van Havig and Ben Love of Gigantic Brewing in Portland, Oregon visit Kirin’s Spring Valley Brewery and are struck by Spring Valley’s 496 IPL. Upon their return to Oregon, Havig and Love begin spreading the word about Spring Valley’s new method to US brewers. In 2018, Kirin presents a poster about dip hopping at the ASBC/MBAA Brewing Summit in San Diego. And last year, John Holl wrote an article about dip hopping for BYO. Seven years is a pretty long incubation period for a cool brewing technique!

Here is the skinny about the what, why, and how.

What? Hops are added to the fermenter before fermentation begins.

Why? Kirin does not explain their original idea, but it likely fell into the “why not” category. The interesting thing, which was probably old-fashioned luck, is that hop pellets accelerate fermentation and produce a different hop aroma than dry hopping later in the process.

How? The Kirin method describes slurry being pumped in line with wort during the fermenter fill.
The original Kirin method requires a few extra pieces of equipment that many smaller craft brewers lack, specifically an agitated vessel and the ability to dose a hop mixture in line with wort, but the technique is really easy to do at home because of the small scale of homebrewing. All one needs to do is add pellet hops to wort after the fermenter is filled and before fermentation begins. That’s it. Hop pellets in wort before fermentation begins. Sounds like there is something missing. Seriously, why in the heck is this so special?

Particulates in fermentation, such as activated carbon, can accelerate fermentation by reducing dissolved carbon dioxide content and boosting yeast cell density. The hop particles from dip hopping behave in a similar fashion. While interesting, this alone does not explain the aroma changes noted when dip hopping is used. But the noted reduction in onion-like flavors does reveal a real difference between dip-hopped beer versus beers dry hopped later in fermentation. Kirin’s research revealed the compound known as 2M3MB or 2-mercapto-3-methyl-1-butanol is the stinking onion.

Data published by Kirin shows that dip hopping not only reduces the concentration of dissolved carbon during fermentation, but also reduces the concentrations of myrcene (a hop aroma deemed undesirable to some brewers) and 2M3MB (via hydrogen sulfide scrubbing) compared to conventionally dry-hopped beers (Effect of Hops Addition to the Fermentation Tank on Beer Fermentation, Kirin Brewing, Tsuchiya, et al., 2018 Brewing Summit). Less myrcene and 2M3MB means that the other hop aromas can really shine, resulting in a cleaner hop aroma when hops are added in the fermenter.

I give this technique two thumbs up; so give it a try!

Response by Ashton Lewis.