Author: Marshall Schott
Dry hopping is the primary method used by brewers to impart tantalizingly fresh hop aroma into styles ranging from Pilsner to Double IPA. Typified by adding a charge of hops to the fermented beer, dry hopping is also said to help prolong precious hop aromas brewers so strongly pine for. Almost as strong as the love for all things hoppy are the opinions regarding the best approach to dry hopping. So far, prior xBmts have shown that tasters are generally able to tell apart beers dry hopped with whole cone hops from pellet hops and, similarly, a beer dry hopped with a larger dose proved more reliably distinguishable than one hit with less dry hops. A variable yet to be tested that has received some attention lately, and the focus of this xBmt, is the impact time has on dry hopping.
When I first started experimenting with this technique, it was commonly recommended to add dry hops to the fermented beer then wait 10+ days before packaging, a suggestion echoed by John Palmer in his popular book, How To Brew:
The best way to utilize dry hopping is to put the hops in a secondary fermenter, after the beer has been racked away from the trub and can sit a couple of weeks before bottling, allowing the volatile oils to diffuse into the beer. (Ch. 5, section 1)
For years, people have relied on this advice to produce fantastic hoppy beers, I think most of us would agree that dry hopping for up to 2 weeks does indeed boost hop aroma. However, with our growing addiction to hop-centered beers has come more research focused on increasing the good qualities of the dry hop while reducing any potential undesirable elements, subtle as they may be, with a lot of talk about grass-like character purported to be caused by hops being in contact with the beer over a long period of time. According to hop-whispering Brewmaster of Firestone-Walker, Matt Brynildson, dry hopping should occur over a relatively short 3 days or less, while Russian River’s IPA aficionado, Vinnie Cilurzo, opts for a 12-14 day dry hop on for the famed Pliny the Elder (For The Love of Hops, pg. 216). A pretty drastic difference between 2 very tasty beers from world-renowned breweries. It was this that got me thinking…
I’ve made plenty of hoppy beer over the years where a long dry hop was employed, though I was quick to change my ways when I learned my favorite commercial IPA, FW Union Jack, was dry hopped for less time. It worked, my beers were at least as aromatic as before, and an added bonus was that it allowed me to reduce my grain-to-glass time for hoppy beers. But my curiosity remained and I recently found myself wondering just what impact, if any, an extended dry hop has compared to a shorter one.
| PURPOSE |
To evaluate the differences between a beer dry hopped for 11 days and the same beer dry hopped for only 2 days.
| METHODS |
My penchant for crisp, easy drinking lager beer had gotten in the way of me brewing a quaffable hoppy style for the last couple months, so I was pretty stoked to get this xBmt going and add some variety to my tap list. I adapted my Lil’ Slack IPA recipe to fit the hops and yeast I had on-hand, bumping up the dry hop additions a bit in hopes of increasing any potential differences that were a function of duration.
A Hoppy Beer
| Batch Size | Boil Time | IBU | SRM | OG | FG | ABV |
| 11 gal | 30 min | 55 | 6.1 | 1.055 SG | 1.010 SG | 5.9% |
Fermentables
| Name | Amount | % |
| Domestic 2-Row | 22 lbs | 89 |
| Munich (10L) | 1 lbs 8 oz | 6 |
| Gambrinus Honey Malt | 1 lbs 4 oz | 5 |
Hops
| Name | Amt/IBU | Time | Use | Form | Alpha % |
| Simcoe | ~15 IBU | First Wort Addition | FWH | Pellet | 9.9 |
| Centennial | ~12 IBU | First Wort Addition | FWH | Pellet | 12.1 |
| Centennial | 30 g/7 IBU | 20 minutes | Boil | Pellet | 9.9 |
| Amarillo | 30 g/6 IBU | 20 minutes | Boil | Pellet | 8.2 |
| Centennial | 40 g/5 IBU | Flameout w/ 15 min stand | Steep | Pellet | 9.9 |
| Amarillo | 40 g/4 IBU | Flameout w/ 15 min stand | Steep | Pellet | 8.2 |
| Amarillo | 60 g | Dryhop 2/11 Days | Dry | Pellet | 8.2 |
| Centennial | 30 g | Dryhop 2/11 Days | Dry | Pellet | 9.9 |
| Simcoe | 30 g | Dryhop 2/11 Days | Dry | Pellet | 12.1 |
Yeast
| Name | Lab | Attenuation | Ferm Temp |
| US-05 American Ale | Fermentis | 82% | 66°F |
I hadn’t been planning a brew day when I suddenly got the urge one Saturday evening, it’d simply been too long (1 week), so after settling on the recipe, I proceeded to my garage for water and grain collection… ahh, the sounds of a mill at midnight. I awoke the following morning and began the 10 gallon batch sparge brew day, combining the hot strike water and grist to hit my target mash temperature of 150°F, a change I made due to my use of the less attenuative Safale US-05 instead of WLP090 San Diego Super Yeast.
I allowed the mash to rest for 45 minutes, stirring a few times throughout.
With the mash complete, I collected the first runnings, added the hot sparge water to my MLT, then collected the second runnings in my kettle and proceeded to boil for 30 minutes. After the boil, the flameout addition sat in the hot wort for 15 minutes then I chilled the wort and racked it to awaiting carboys.
Due to my warmer groundwater, the full fermentors had to be placed in a temperature regulated chamber for about 2 hours in order to drop to my target fermentation temperature, after which I sprinkled the dry yeast directly onto each wort. Signs of activity were evident the following morning.
Fermentation continued similarly for both with activity seemingly peaking around the 36 hour mark. Going along with another one of Brynildson’s recommendations to dry hop prior to fermentation being fully complete, I added the long dry hop charge after 3 days of fermentation, observable activity had slowed quite a bit. I vacuum sealed the combined short dry hop charge and stored them in the freezer.
After 9 days, it was time to dry hop the second batch. The scent emanating from my chamber at this point was rather sublime, if any indicator of what was to come, I was in store for a tasty beer.
About 24 hours after dry hopping the short dry hop batch, I began cold crashing, returning 12 hours later to add gelatin, which I allowed to do its thing for an additional 12 hours before packaging. An interesting observation I made at this point was that the trub from the short dry hop batch appeared noticeably more green than that from the long dry hop batch. We all learned in jr. high science that chlorophyl gives plants their green color, but that’s not all, many believe it is also partially responsible for the grassy flavors found in some beer.
I’ll be honest, witnessing this did little to ease my concerns about creating a beer that smelled and tasted like my compost bin. I kegged the beers, placed them in my keezer, then let them sit on 45 psi of CO2 for 12 hours before purging and setting to serving pressure. I began serving them to participants 3 days later, at which point they were perfectly carbonated and mostly clear.
| RESULTS |
A total of 19 people participated in this xBmt including multiple BJCP judges, experienced homebrewers, and craft beer cognoscenti. Each person was blindly served 2 samples of the long dry hop beer and 1 sample of the short dry hop beer in different colored cups then instructed to select the one they perceived as being unique. To achieve statistical significance given the sample size, 10 participants (p<0.05) would have had to accurately identify the short dry hop beer as being different. In this case, a statistically significant 12 tasters (p=0.003) were capable of making the correct selection, nearly all of whom reported feeling confident in their decision based solely on aroma. These results suggest the length at which a beer is dry hopped does seem to make a difference, that folks can reliably distinguish a beer dry hopped longer from one that sat on dry hops for a shorter time period.
Following the triangle test, those who correctly selected the short dry hop beer as being different proceeded to a brief evaluation comparing only the 2 different beers, still blind to the variable being tested. In terms of aroma, 5 of the 12 reported preferring the short dry hop sample, 6 perceived the samples as having no difference, and only 1 preferred the long dry hop beer. Flavor preference was a different story with 7 preferring the short dry hop beer, 4 saying they liked the long dry hop beer better, and only 1 endorsing no difference. Mouthfeel preferences were more evenly distributed, 5 saying like the short dry hop beer better, 4 preferring the long dry hop beer, and 3 noting no difference.
Overall preference, surprisingly, was split almost down the middle with 5 endorsing the short dry hop beer while 4 preferred the long dry hop beer. The last 3 reported having no particular preference for either beer, despite noticing differences between them.
My Impressions: For the first time in awhile, I was able to distinguish between these beers on a fairly consistent basis, both side-by-side and in quasi-blind triangles served to me by others. Aromatically, I perceived the short dry hop beer as possessing more dank, resinous character that was layered with citrus and tropical fruit notes, while the long dry hop beer came across as having little dank character at all. In terms of flavor, the long dry hop beer was certainly hop-forward, which to me was reminiscent of a clean juice blend, with a pleasant maltiness in the finish. The short dry hop beer had the same juice-like flavor combined with a pungent kick of resinous, danky deliciousness. While I thought both beers were fantastic, I’ll definitely be sticking to shorter dry hop lengths due to my preference for punch-you-in-the-teeth hop character as well as shorter turnaround times.
| DISCUSSION |
I find the results of this xBmt encouraging. The data supports the notion that dry hop length does indeed have an impact on beer, but there is no indication one way is better than the other, neither method produced a bad beer. I found it interesting only one person noted perceiving a “grassiness” in the long dry hop sample, a comment that came following completion of the survey and revelation of the nature of the xBmt. I couldn’t detect this in the slightest. I’m not all comfortable recommending people use my subjective impressions to make decisions, partially because I could have a shitty palate, but it’s also highly likely dry hop character as a function of time is different for every hop, thus results from the hop bill I used may not translate to other beers. I guess what I’m saying is, try it out for yourself, determine your own preference, and don’t fret if you end up changing things up at some point.
Lastly, these results really make me want to revisit a technique a prior xBmt suggested may not have all that significant of an impact– double dry hopping. When I initially tested it, the separation between the first and second dry hop additions was only 2 days, now I’m curious if perhaps a longer span between the additions might not produce a more distinguishable result. Best of both worlds? I guess we’ll have to wait and see.
If you have any thoughts about this xBmt, please share them in the comments section below!
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56 thoughts on “exBEERiment | Impact Dry Hop Length Has On An American IPA”
I believe your findings line up with my assumptions on tasting. When I read pro-comparisons of any beer and obvious disparity, then couple that with wildly differing results from homebrew competition results, I wonder how any brewer can have confidence in other opinions. Gordon Strong also said that competitions were a crap-shoot – “you just have to get a set of judges to agree on your beer”. I’d like to see BJCP judge characteristic that includes a flavor profile ranking, then place those judges in charge of categories they have the ability to distinguish.
Hey Marshall,
I know this idea might cause unwanted headache for you… (Can you tell I’m gonna continue anyway?)… but have you considered running the typical blind tasting experiment alongside another run where you reveal the variable? It might be interesting to see whether the results would be much different if another control group knew the variable. Then again, it might be too much work. Admittedly, I don’t know what it’d accomplish in the grand stream of things, except to see if a bias in the tasting would make a difference. You could actually run the blind test, set up a second round and reveal the variable to see if that person coul then pick it out. Just a though… Probably a bad one.
See how easy it is for me to create work for you. 🙂
Cheers dude!
Actually, we changed the survey a few months back to test how knowledge of the variable might impact perception. Following the first blind triangle, the nature of the xBmt was revealed and participants took the triangle test again. Surprisingly, over about 10 different xBmts, I believe only 1 person changed their response… and it was from correct to incorrect!
We ended up deleting that question since it was obviously meaningless and made the survey longer to take.
I’ve been hoping you would do this for awhile, and it didn’t disappoint! I certainly prefer the shorter dry hops, if for nothing more than decreasing production time. Good to know that I’m not missing out on anything by not letting them go longer.
Thanks. A fun read, as always.
Curious – were the more water-logged long term hops easier to transfer?
I’m not sure I understand your question. I didn’t transfer any hops, just added them to the primary (no bag) 9 days apart from each other.
Which beer was easier to transfer from the fermenter to a keg – without pulling in hop matter? Did one have a more compact trub layer?
They were both equally as easy.
I wonder of the two beers, which would maintain the hop aroma the longest. Or if any impact at all.
They’ve been around for awhile now and the short dry hop is definitely more hoppy, to my palate at least.
Another excellent test. You guys are on a role with good ones! Keep them coming! A few questions:
1) how much gelatin are you using these days per 5-6 gallon primary fermenter?
2) If I am reading this right, the short dry hop beer sat 9 days in primary, then got a dry hop charge. It was then crashed 24 hours later, gelatin added 36 hours after dry hop and racked 48 hours after dry hop? So, really, it was being racked about 48 hours after the dry hop charge? That’s pretty impressive. It’s almost like 24 hours is enough to get good flavor since it was being chilled and covered in yeast pretty quickly after 24 hours anyway! I’m totally a proponent of the dank flavor and will definitely be doing this!
A personal observation on grassiness. I have only tasted what I would consider grassiness in a beer that was dry hopped with noble hops, I think it was hallertau or saaz. I’ve tasted the same beer as someone else at the same time, and I thought it was very hoppy and delicious, and they said it tasted “grassy.” I think some people are mistaking delicious hoppiness for “grassiness” honestly. I think people just have differences in taste buds on this a lot.
1. Same as always- 1/2 tsp
2. That’s right 🙂
The only time I’ve tasted grassy in a beer is when it had hallertau in it. Honestly, I like that flavor when I am digging in to a German pilsner, vienna or an Oktoberfest (which doesn’t mean other noble hops aren’t valid for the styles, just my preference). Any other types, not really. I’ll use it in some wheat beers at low IBUs sometimes too. I’ve never tasted grassy in a beer I’ve made or in someone else’s beer where I wasn’t positive or at least confident that the hops used where hallertau. Everything from a tiny bit of hops to a ton of hops.
I’m no “professional”, but consider myself decently capable of distinguishing flavors in beer. I’ve never experienced this “grassy” flavor so many people talk about. (I’m not saying it doesn’t exist, but …)
I’m wondering how the characters would compare if the short-dry-hop were added at the same time as the long, then removed at 2 days. Technically the long-hop batch had 9 days longer to age after the hops were hit the beer.
There could be some “smoothing out” that starts happening as soon as dry hops hit the beer?
In any case, nice to see another confirmation that 2-day dry hopping is valid for smack-you-upside-the-head levels of hops.
Have the two batches become closer in their qualities as they have aged or has the differences remained ? In other words has the increased aroma that you achieved in the short hopped beer diminished as it conditions in the keg ? Just wondering. Thanks !
I still perceive short as being more hoppy.
I think you are on the right track with the multiple addition vs. single addition question. Some of my favorite brewers use a 5/3/2 day or 3/2 day multiple treatments (and I’ve heard of others doing 7/3 or 14/7/3.) So I am betting you’ll find something your hopbomb loving nose will love.
“Going along with another one of Brynildson’s recommendations to dry hop prior to fermentation being fully complete, I added the long dry hop charge after 3 days of fermentation, observable activity had slowed quite a bit. I vacuum sealed the combined short dry hop charge and stored them in the freezer.”
There were two variables in your dry hopping process, not one, and we cannot conclude anything about dry hop length as opposed to dry hoping during fermentation.
Ahck, that came across as snarky. Sorry. I was right, but I’m feeling rude. I’m actually planning an IPA and I’m thinking about three addtions: fermentation dry hop, longer post-fermentation dry hop, short thrid dry hop. It seems like we’ve learned something, and that is good, even if we haven’t quite learned something determinate yet.
I had the same thought as you. I think the comparison of the carboys post fermentation shows why when you start dry hopping is an issue – the hops were covered in yeast in the “long dry hop” carboy – which means less possibility for the beer to interact with the hops. As well as that, it is a common understanding that large quantities of yeast will lower hop character – it is possible that flocculating yeast took some of the dry hop character.
Cool experiment though – it definitely shows that how you dry hop makes a difference.
I don’t think they were covered in yeast, I think their color was absorbed into the beer. Personal opinion.
@phonos It’s even more complicated than that. CO2 bubbles during fermentation may carry away volatile hop aromatics. Additionally, I’ve seen some stuff about hop-yeast glycosidic reactions that suggest that yeast may actually transform some hop compounds, whether beneficially or not. (I recall something about some compound that isn’t actually aromatic but is a precursor to something else which is.) Additionally, as the conclusions of the article suggest, there may be no best way to do it.
Dang it! I just hooped a DIPL yesterday, but I am 99% sure I won’t have time to bottle it until this Saturday or Sunday (which was the original plan). Now I want to cold crash it tonight and bottle it tomorrow, but I am 99% sure I won’t have the time.
Though maybe, it is only 3 gallons and that doesn’t take nearly the time to bottle as the 5.5 gallons of bitters I bottled yesterday did. And my couch is comfy for if I upset the ruler of the house.
Oh, I am also sad, because it is a Cascade/Chinook mix and when I went to dry hop, I cannot find my repackaged cascade and Chinook! I saved off half an ounce of each from the 4oz of Cascade and 2oz of Chinook I was using in the recipe for the DIPL. I gave up after literally emptying everything from my fridge, freezer and chest freezer looking for the vacuum pack.
I gave up and just cut open a 1oz package of cascade and dumped it in to the carboy.
At least I had a nice flameout addition of Chinook. It was 2oz of cascade at 60min, 1/2oz Chinook 45min, 1oz cascade 15min, 1oz Chinook 10min, 1/2 of cascade and Chinook at flame out and I was saving the last half an ounce of both for dry hopping 🙁
Hi prof! This is slightly unrelated, but I did not get why you batch sparged this one, rather than use your usual no-sparge routine?
I no sparge 5 gallon batches and batch sparge 10 gallon batches, only because I don’t have the capacity.
Agree with the above poster, in that we have a couple of variables.
1) dosing time – ie day 3 and day 9 of primary fermentation
2) length of time on hops ~168hrs or 24hrs before cold crashing.
ie.. was hte nature of hte grassyness something expressed due to biotrasnformation of a compound yb the active yeast, rather than the duration of hopping?
Now that opens a whole raft of experiments.
It would be really awesome to see an exBeeriment testing dry hopping after fining as well. I’ve been wanting to do something like that for awhile but have been worried the yeast might not like chilling and then warming and then chilling again (unless the dry hop just takes place cold which seems like a less than ideal situation.)
On the list
please, please!
Totally ordering a My Kind of Science hoodie, great design. You have inspired me to have a go myself! Always fancied doing something creative.
One for the future. Loose dry hops vs in a bag / tea capsule thingy. Given the difference here I suspect it will be minimal but worth keeping in mind. Prob bigger fish to fry first!
Keep up the awesome work!
Great xBmt! The question is, what happened to the “dankness” that you described being in the shorter dry hopped beer but not in the longer dry hopped beer? If it falls out on it’s own (due to binding with other molecules or whatever the mechanism would be) during the longer dry hopping time period, then the beer with the shorter dry hopping time period would eventually demonstrate the same effect in the keg, right? Perhaps it is the activity of the yeast still in suspension that affects the longer dry hopped beer? Temperature might also play a role in the diminishing of the “dank” character, but if that were the case then eventually you would probably still see that diminishing effect occur in the keg for the shorter dry hopping time period beer.
After reading this I also can’t help but wonder if different dry hopping schedules affect different hop varieties differently, or if there is a generalization that can be made.
I compared both beers side by side a couple times yesterday, they’ve been on tap for just about 3 weeks, which is longer than I usually have beer around– I still perceive the short DH batch as being noticeably more hoppy, both dank and fruit, than the long DH batch. But both are still obviously hoppy beers.
I’m starting to wonder if the yeast isn’t pulling a lot of hoppiness out of the beer as it drops. My beers taste like super hop bombs while cloudy, but it dissipates as the beer clears (of course time is at play as well, so it’s hard to separate.) That is why the fining and then hopping would be interesting.
Always rigorous and largely intriguing, I always enjoy reading about your research.
I noticed that the force carb time and pressure has changed a bit since I started reading your blog. I believe you started at 30 psi and two days, went to 40 psi and 24 hours, but now you are at 45 psi and 12 hours. Any noticeable difference? Besides time savings?
It all works well, I choose based on the day 🙂
Hey Marshall,
A little off topic, but I’ve noticed that you ferment with just an aluminum cap on the carboys for a few days before putting a air lock on it. Is this for a specific reason? Did I miss an exbeeriment about this?
Hi Jamison, I’ve actually not done an xBmt on this, but I’ve yet to have a problem in the hundreds of batches I’ve made with foil in place of an airlock. In fact, some contend the small amount of backpressure created by the airlock could impact the yeast. I’ve even fermented with the foil the entire time, works great!
I’ve been doing this for several years with no problems too. However, your pressure xBmt seemed to show there wasn’t much difference under pressure, at least for those conditions. I just do it to save vertical space in my fermentation fridge.
I used to work in the tasting room at a craft brewery where they dry hopped in the serving vessels and just left them in as the beer was served. For the less popular beers the hops must have been in there a couple months at least and I definitely noticed a major increase in grassiness as it aged (the typical citrusy hop flavor diminished and the beer was overpowered by grassiness, not a good thing) but they continued to do so… needless to say, their dry hopped beers were always best in the first few days/ week. this xBmt confirms why I thought about their dry hopping practices
Just found this and so glad I did. Great article proving that I don’t have to wait to get the benefits of a longer dry hop and spared me the concern of “wasting” hops by dry hopping for too little time.
Thanks!
@bry_p_a
Has anyone tried doing both? i.e. Dry hopping on Day 3 AND Day 9, so you get to enjoy both advantages in terms of flavor and aroma? It may seem like too much work, but not really, as easy as adding another sanitized bag with hops to a carboy/bucket (and of course waiting the extra week). I feel like I would just add an extra split ounce to each charge, like instead of using 4 oz total, with 2 oz in each charge, I would use 2.5 oz in each charge for a total of 5 oz. Will try this on my next batch since I usually do an 8 gal batch split into two 4 gal batches with 2 diff yeasts; I’ll use the same yeast this time and do a little xBmt of my own! Cheers
This was one of my thoughts as well. Did you end up doing both? If so, How did it go?
Well, did you do a diy exbeeriment? What were the results for you? I’m interested to hear!
Wow I’ve been leaving the dry hops in the keg until the keg is kicked but I’m going to change this next batch because of this experiment and see how it goes.
Cheers 🍻
Marshall,
What’s exactly is the reasoning for racking off of the trub before the second dry hop?
Finally got around to trying a short dry hop beer. I put in 6 oz of pellets to a IIPA and let rest 24 hrs, then cold crashed for 24 hours and racked to keg. I did NOT do a control long dryhop batch, but this beer definitely seemed to have a character that is different from what I am used to. It was a much more dank character, more like if you add dry hops to the serving keg but not as vegetal. I didn’t like it as much at first, but it is pretty good after a few days in the keg. I think I’ll try a split batch, with a long dry hop on one and a short dry hop on the other and see what I think. Thanks. This is an interesting one.
Have you tried half 9 days and half 2 days for a double hop experiment ?
Nope.
It says that the long dry hop beer was dry-hopped on day 4 into fermentation. Perhaps if you had waited until fermentation had ended then it would have been more dank. So like ferment both beers for 10 days. Then dry hop one for 7 days and the other for 1 day. Some beers like Pliny are dry-hopped twice after fermentation ends one on top of the other perhaps this is to layer in the qualities of both a long and short and perhaps warrants an experiment?
As usual another great study.
I have a little follow-up question : when you determine the time of DH, I see that you include the cold crash time. I was lead to believe that when the temperature was low, there was not a lot of exchange between hops and wort/beer. In my case, I count the days of DH before cold crash only (and I don’t add the couple of days I usually cold crash for). What is your take on this? If there are some noticeable exchanges of aromas at low temp, it would give me some ideas about DH in kegs at low temp!
Cheers!
Here’s another xBmt we did on dry hop temperature: https://brulosophy.com/2016/01/18/dry-hop-temperature-warm-vs-cool-exbeeriment-results/
My thoughts – add both the short and long hop at the same time and then cold crash and rack one immediately and wait the extra time for the other before doing the same. Adding the long dry hop at different times (active fermentation vs. once fermentation complete) could have been a variable that affected the results.
Would this be any different if I was bottling instead of cold crashing and kegging? Would the hops need more time to settle to the bottom of the carboy?