One of the key factors of the mission of the Brewminaries is to help our brewers make better beer. One component of that is experimenting with different aspects of brewing and demonstrating how the choices we make in our brewing processes affect the beer we make. Each year, we ask our members to submit their brewing-related queries and vote on which experiments they would be most interested in seeing.

This year, our members decided they wanted to learn more about dry-hopping and biotransformation techniques.

What is Biotransformation? And how does it differ from dry-hopping?

So. Yeast eats stuff, right? Primarily we think of it eating the malt sugars and converting them to alcohol, but it eats other stuff too, e.g., hop oils. Some yeast strains, when they eat the hop oils, they actually transform it into an entirely different compound (e.g., transforming geraniol into beta-citronellol). So, when we add hops during fermentation, when the yeast is very active, it will interact differently with the hops than when we add hops after fermentation is complete (or mostly complete), when the yeast is napping. (For more info on yeast and hops under normal, non-biotransformation conditions, see this article from brulosophy)

So what is the difference, actually? Taste? Mouth-feel?

That’s a great question. Stay tuned!

Here’s what we did:

We compared four different conditions: a control condition that was not dry-hopped at all, a condition that had hops added after 24 hours (the Biotransformation condition), a condition that had hops added after one week (the Dry-hop condition), and a condition that had hops added after both 24 hours and one week.

One more cool thing: at around the time we were conducting the experiment, Coney Island Brewery held its second annual Wort Share. We decided that since we wanted to use a simple grain bill, to highlight any differences coming from the hops, and because the Coney Island wort was all the same, made at the same time and in the same way, it would make a great base for our experiment.

The Coney Island wort was all 2-row, 1.053-1.054 OG. I took 10 gallons of it, which seemed like a good idea until I had to haul it all to my third floor apartment.

Carrying 10 gallons of wort to my third floor walk-up. I need to work out more.

The other nice thing about the wort share is we had many people going to pick up the same wort, and a few of my fellow Brewmies (Roman Goyenko, Dustin Wheeler, and Brett Vanderbrook) were willing to donate some of their wort the cause and brew up a batch. We each picked a condition and went to town.

The Recipe

After we got our wort home, we did a 1-hour boil. For a 2.5 gallon batch, we added:

.25oz Magnum pellets at 40 minutes

.25oz Mosaic pellets at 5 minutes.

We then pitched Wyeast London Ale III yeast

We used no water additions, and pitched the yeast directly into the wort (no starter).

The Conditions:

Condition 1: Control (Colleen)

No dry hop additions.

Brewed on 2/23

2.5 gallon batch

OG post-boil: 1.059

Condition 2: Biotransformation (Brett)

2.5 gallon batch

2 oz Mosaic, 24 hours post-pitching yeast

Brewed on 2/25

OG post-boil: 1.069 (Nice)

Condition 3: Dy hop (Dustin)

2.5 gallon batch

2 oz Mosaic, 7 days post-pitching yeast

Brewed on 2/25

OG post-boil: 1.040

Condition 4: Biotransform + Dry hop (Roman)

5 gallon batch

2 oz Mosaic, 24 hours post-pitching yeast

2 oz Mosaic, 7 days post-pitching yeast

Brewed on 2/23

OG post-boil: 1.060

The Judging Round

In order to learn about how people perceive each of the different conditions, we assigned each beer a label, A-D, and had our Brewminaries at the meeting try each beer. Our tasters then completed a survey in which they were asked to identify which beer was which. For bonus points, they could also guess what the OG of each beer was post-boil. (Because, see above, the OG’s were quite different). Respondents received 4 points for each beer they correctly identified, and 1 point for each OG they guessed correctly. The Brewmie with the most points would win a fantastic prize!!! And bragging rights!!!

Finally, there was a place where Brewmies could describe each beer.

In total, 36 Brewmies completed the survey. Not bad for a Wednesday.

On average, Brewmies got 7 points. Out of 20. Basically, most Brewmies correctly identified 2 of the beers.

Tasting and filling out the survey (sometimes it's good to be on your phone during a meeting)

The Results:
Control Beer. 52% of Brewmies correctly identified this beer. So, if you’ve got to decide between Contains Lots of Hops and Contains Fewer Hops, our Brewmies have got you covered! In their qualitative feedback, many Brewmies correctly described the beer as less hoppy than the others. As should surprise no one, this beer was not a fan favorite. Comments ranged from “My least favorite beer :-(“ to “Boring”. I brewed the Control beer, remember, and I’d be offended if I didn’t completely agree. The Brewmie who commented that something must have gone horribly wrong during dry hopping was exactly correct: I committed the horrible horrible sin of not dry hopping my beer. May no one ever commit this error again.

Dry-hop (Hops added after 7 days). Performance was a little bit lower here, with 41% of Brewmies correctly identifying it as the Dry Hop Only beer; however, the second-most common response was that this was the Bio + Dry Hop beer, so 72% of Brewmies did correctly identify that this beer was dry-hopped. Opinions on this beer ranged from “best of the bunch” to “least favorite”, and was largely characterized as having juicy/fruity or dank hop notes.

Bio Only (Hops added after 24 hours). This one was tricky. For reasons unbeknownst to the brewers, this beer wound up being a heck of a lot darker than the others, and something odd happened with its flavor. Only 19% of Brewmies correctly identified this beer, though 52% identified it as one of the Biotransformation conditions. Some people described this beer as having too much sweetness or diacetyl; others described it as a West Coast IPA.

Bio + Dry-hop (Hops added after 24 hours and 7 days). This one. This one was the king of all the experibeers. 36% of Brewmies correctly identified this beer, but 78% identified this as one of the Biotransformation conditions. Heart-eyes emojis burst from the comments, with people describing this as their favorite beer. Descriptions ranged from lively and tropical to fruity and clean.

And finally, our winners: Larry Ubell and our illustrious Vice-Dic, Ben Kainz, who got 18 points each (meaning they correctly identified all four beers, plus two of the OG’s correct)!

In Conclusion

Perhaps the best conclusion we can draw is that Roman makes great beers, and that Brewmies are pretty great at identifying dry-hopped beers. But, the biotransformation + dry-hop condition did definitely impart some interesting flavors that differed from the dry-hop only condition.

Keep in mind, the effects of biotransformation differ based on the yeast and hops used, so an experiment of this kind isn’t going to be particularly generalizeable to new hops and yeasts. If you want to learn how your dry-hop schedule will affect your beer, the best way to find out is to try it out.

Have you experimented with hop schedules and want to tell us about it? Leave us a comment and tell us about it!

EXPERIMENT: Dry-Hop vs. Biotransformation