Most homebrewers understand that dry hopping is necessary to maximize hop aroma in a beer; however, there are several considerations to this step. Add hops during active fermentation or after, or both? How long do you leave hops in contact and at what temperature? At what rate do you dry hop to get the biggest impact? We asked three pros known for their IPAs to answer these questions and more. Their answers varied.
Scott Janish is Co-Founder of Sapwood Cellars, in Columbia, Maryland
I tend to think of whirlpool hopping as the start of aroma and the base of flavor needed to balance a heavy dry-hopping load. Dry hopping is where you can get that “wow” jump of aroma out of the glass that only a handful of whirlpool hops alone can even come close to (like RiwakaTM and Idaho 7TM).
We’ve settled on a rate of ~4.4 lbs./barrel (2.25 oz./gallon or 17 g/L) for dry hopping IPAs at Sapwood Cellars. Going higher with the use of something like CryoTM can lead to a punchy beer, but going much higher with all T-90 pellets has the potential of an aggressive vegetal-like bite to the beer that’s not enjoyable (especially if the heavy dry-hopping load is done at warmer temperatures and rousing the hops, which might over extract).
We like to dry hop post-fermentation and post-crashing down to about 34 °F (1 °C) for both ales and lagers. We typically dry hop everything in two stages (split the additions in half, leaving CryoTM hops for the second addition). The first addition goes into the fermenter in the morning and gets burped (sending a shot of CO2 into the fermenter from the bottom to rouse the hops) that day and burped again the next morning. The tank gets dropped towards the end of that second day and again at night. The following day we repeat with the second dry-hop addition. We hope breaking the charges in half gives the hops a better chance at extracting upon contact with the beer. There is some research that would back this up, but that research was not done on larger brewing tanks.
We’ve always favored dry hopping at cooler temperatures, using the literature as a guide that the colder temperature still extracts the compounds from hops we are after with good efficiency (monoterpenes, thiols) but more importantly doesn’t extract more woody, spicy, and resinous compounds (hydrocarbons). The colder you dry hop, I think the more important it is to rouse the hops because they will want to drop to the cone quicker and their contact time is reduced, which is why we burp the fermenters.
In addition to the hazy IPAs, we dry hop some of our sours too. We have become fans of aging a pale ale base (before dry hopping) in wine barrels with various microbes that can work on the hop compounds, creating a fruity/funky base over the course of 6–12 months, which will then get a healthy dry-hop addition before bottling. CryoTM hops seem to work especially well with these beers to reduce astringency, which is extra important if the beer’s pH lowers significantly during aging. Bioengineered thiol-producing strains can be fun choices for primary fermentation in these situations to maintain a fun fruitiness during aging.
The most important thing to consider in your dry-hopping routine is oxygen! Nothing will negate all your efforts so quickly in a hoppy beer (especially hazies) as oxygen introduction during transferring, dry hopping, or packaging. Consider tossing a gram of metabisulfite into your dry-hop bag for some added insurance to oxygen. Look into the science of mash hopping and the ability of hops’ alpha acids to complex problematic metals that are prone to oxidation. Essentially, lowering these concentrations of metals before dry hopping and potential oxygen ingress can help the shelf life of IPAs.
Oli Banks is the Head Brewer at Stigbergets Bryggeri in Göteborn, Sweden
For me, dry hopping lends a much more bright and intense aroma from the hops that can’t be replicated from whirlpool additions alone. I like to add from 0.67–2.1 oz./gallon (5–16 g/L) of T-90 pellets as a dry-hop addition — the lower end for hoppy lagers and pale ales, and the higher end for IPAs, double IPAs, and triple IPAs. Going above this rate I find you end up bringing out more of the vegetative character of the hops rather than the lupulin and oils that most people are aiming for. You can go above this with the use of CryoTM hops or liquid hop products like Spectrum from Barth Haas or Hop Kief from Freestyle.
For 90% of our beers we dry hop post-fermentation and at a lower temperature to minimize scrubbing, (having the fermentation blow off the more volatile compounds). These are added at around 57–61 °F (14–16 °C) depending on the beer, mainly to minimize time for hop creep to start to set in.
Then we normally keep the dry hops in contact for 36–48 hours, max. We mix the tank during hop additions to increase extract rate so we try keep the beer actually on the hops for as little time as possible. Sometimes for double dry-hopped beers we’ll add CryoTM hops or Spectrum towards the tail end of fermentation to encourage the biotransformation a bit more before adding the main charge after fermentation. I’m not yet personally convinced it makes a great deal of difference compared to adding it all at the end. It’s definitely an area where more research needs to be done.
In addition to the hop-forward styles that are always dry hopped, we sometimes dry hop lagers that may be lacking a little top note with as little as 0.1–0.25 oz./gallon (1–2 g/L) with a noble hop just to make the aroma pop. With some saisons we’ve also found dry hopping can be a nice addition, but generally we leave the hops to the hop-forward beers.
One last piece of advice for homebrewers: Try get out as much yeast prior to dry hopping as possible. This is easiest if you have a conical fermenter and can dump the yeast, but even transferring off of the yeast to a second vessel should be considered. It definitely helps with extraction of hops and helps them shine a lot more.
Jesse Ferguson is Co-Founder, Head of Product, Brewer, and Distiller at Interboro Spirits & Ales in Brooklyn, New York
Dry hopping extracts just the oils and almost no bitterness, so adding hops post-fermentation is the best way to add a punchy hop aroma to your beers without any additional bitterness. We dry hop our hazy IPAs with roughly 3–4 kg per barrel (3.4–4.5 oz./gallon or 25–34 g/L). Our West Coast IPAs get more like 2–3 kg per barrel (2.3–3.4 oz./gallon or 17–25 g/L). Both beers end up with roughly the same weight of hops per barrel; the West Coast IPAs just get more in the kettle, either as a late-boil or whirlpool addition.
We’ve found hop oils are extracted more readily at warmer temperatures, so we dry hop at post-fermentation temperature. For dry-hopped lagers we ensure the beer passes a diacetyl test, then dry hop at that diacetyl rest temperature (typically 60 °F/16 °C) prior to cold crashing. Dry-hop additions are made immediately upon reaching terminal gravity (after we remove yeast), or for double dry-hopped beers we like to add a small amount of hops during fermentation, on day one usually, prior to the second addition post-fermentation. Dry hops are left in contact with the beer warm for two days prior to crashing, when we dump the hops from the cone.
Beyond technique and choosing hops with a great aroma, selection of hop varieties and even pellets is also important. Look for hops with lower alpha, higher oil content, and selecting a softly packed pellet that will easily “dissolve” (fall apart) in the beer for max extraction.
Lastly, think beyond just IPAs for dry hopping — any beer that you want an additional hop zing can be dry hopped — for us this has included saisons and even session stouts.