Recirculating Dry Hops: More Aroma Oil Extraction in Less Time

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ocluke

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I recently wrote a blog post on my Recirculating Dry Hop Setup, and thought I would post the configuration here as well. If you want to learn more about the theory behind it, read the thesis that I discuss in the blog post.

Last year I came across an Indie Hops blog post titled, “More Aroma Oil, Faster: The Dry Hopster’s Holy Grail.” It reported on research by Peter Wolfe and Dr. Tom Shellhammer at the Oregon State University Department of Food Science. The study was published as Peter Wolfe's thesis: A Study of Factors Affecting the Extraction of Flavor When Dry Hopping Beer.

The main takeaway from the study was that by agitating dry hops, one can extract more hop oils from the hops. This isn't surprising considering in the commercial setting, Dogfish Head, Russian River Brewing and Firestone Walker use a “Hop Cannon”; Sierra Nevada uses a “Torpedo,” and New Belgium and Stone use “The Slurry Method” (for more on those setups, read chapter 8 of For the Love of Hops, by Stan Hieronymus).

The second takeaway was that aroma compound extraction occurred extremely fast (as in hours, not days).

I wanted to devise a way to agitate dry hops on the homebrew level. Here's what I came up with.

http://postimage.org/

Here's a video of it in action:
[ame="http://www.youtube.com/watch?v=Ax-8Kh9NTj0"][youtube]Ax-8Kh9NTj0[/youtube][/ame]
 
It might help to note that I have already dry hopped 3 batches with this setup, and the results are excellent.
 
Interesting post. I particularly liked that graphs on your blog. I dry hop in bags in the keg at room temp while it's carbing. I set the PSI to 30PSI and roll/shake the keg periodically over the course of a week until it's carb'd. This might be an alternative method for those that keg but lack a pump/conical setup. I've had great results with it at least.
 
The graphs were from Peter Wolfe's thesis. They were not my own. He gave me permission to use them (citing the original source).
 
Good post, I just ran into Wolfe's thesis and found it really interesting. I've had inconsistent results dry hopping and hope this might be the optimal way to do it, and best of all it doesn't take very long.

I really like your agitation setup. I don't use conicals, but I'm thinking maybe I can do the same thing with a corny keg using the gas in and liquid out connected to a chugger pump. Seems like a fun experiment at least =]
 
I'd assume he's using pellets.

Correct assumption. I typically fill the pump line with co2, then connect it to the conical and prime with beer. I then add the pellets, let them soak for an hour to break apart, and then turn on the pump recirculation.

metabrewing.com - a homebrewing blog focused on experimentation, techniques, wild yeast, sour beers, hop aroma and whatever else sneaks its way in.
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So by pumping out the racking port and back in the bottom I assume this prevents oxidation. I like it.


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Having a purged and closed system prevents oxidation. Having the beer flow out the racking arm and in through the dump valve prevents cloging and increases agitation.

metabrewing.com - a homebrewing blog focused on experimentation, techniques, wild yeast, sour beers, hop aroma and whatever else sneaks its way in.
@metabrewing (Instagram, Twitter, Facebook, Google+)
 
any way to do this without a pump? We have a kegerator, I was thinking with the co2 tank, purge the beer in secondary to rouse the hops.
 
any way to do this without a pump? We have a kegerator, I was thinking with the co2 tank, purge the beer in secondary to rouse the hops.

Peter Wolfe does not recommend rousing hops with CO2. I think I cover the theory in my blog post (link in the original post of this thread), but if not, it is covered in Wolfe's thesis. The basic premise is that it scrubs away volatile aroma compounds.

metabrewing.com - a homebrewing blog focused on experimentation, techniques, wild yeast, sour beers, hop aroma and whatever else sneaks its way in.
@metabrewing (Instagram, Twitter, Facebook, Google+)
 
I have been doing this (torpedoing -Sierra Nevada) for almost 2 years now. ALL of my
hope bombs get it now. It works great. I use a whole house water filter and recirc the
wort in the keg.
 
I apologize if this is obvious but do you filter the beer to remove the pellet residue when transferring from the fermenter to the serving vessel?
 
I apologize if this is obvious but do you filter the beer to remove the pellet residue when transferring from the fermenter to the serving vessel?

I do not filter, but I cold crash and fine. If I'm using my conical, I also do several dumps.

metabrewing.com - a homebrewing blog focused on experimentation, techniques, wild yeast, sour beers, hop aroma and whatever else sneaks its way in.
@metabrewing (Instagram, Twitter, Facebook, Google+)
 
I have been doing this (torpedoing -Sierra Nevada) for almost 2 years now. ALL of my
hope bombs get it now. It works great. I use a whole house water filter and recirc the
wort in the keg.


Oooh, this sounds like what I might want to do. Any chance I could get the details :D
 
I have been doing this (torpedoing -Sierra Nevada) for almost 2 years now. ALL of my
hope bombs get it now. It works great. I use a whole house water filter and recirc the
wort in the keg.

The torpedo method, while coming from a similar theory, is different than the method in this setup. It would be interesting to test various agitation methods against each other. Maybe someone will take this on.

metabrewing.com - a homebrewing blog focused on experimentation, techniques, wild yeast, sour beers, hop aroma and whatever else sneaks its way in.
@metabrewing (Instagram, Twitter, Facebook, Google+)
 
So what was the final conclusion with this experiment? Do you still use this method? Run into any problems?
 
Bueller?

I'd like to try this method if you could share your results and what issues you ran across. But if it's not worth it I'd rather not spend the time and money trying to recreate it.
 
Thanks for this post and for correcting the link. I've been thinking about this and you've provided my tipping point. Have you or others seen variations where the hops reside and are contained in a second container? Seems like it can keep a lot of matter out of the fermenter
 
Thanks for this post and for correcting the link. I've been thinking about this and you've provided my tipping point. Have you or others seen variations where the hops reside and are contained in a second container? Seems like it can keep a lot of matter out of the fermenter

Are you referring to a container inside the fermentor, such as a hop bag, or outside of the fermentor, such as Sierra Nevada's hop torpedo? I'm sure there are a number of ways you could experiment.
 
ocluke - this looks excellent and something I want to try asap!!

A couple questions -

Have you ever done this with whole cone hops (I grow my own and I am looking to maximize the aroma from them) and this looks like the perfect solution...

Second - I'm assuming you dump all the yeast first? I have an SS Brewing Chronical and I'm anxious to try this setup on my next brew.

I can't tell ya how much $$$ and hops I've probably wasted/underutilized... I dry hop in a SS canister in my keg and when I go to clean them, the hops still always have SO MUCH aroma left in them...
 
Ocluke - just read your blog post regarding this - very nice write up.

Another question came to mind - as mentioned above, I have an SS Chronical which has a good length Racking arm... So I'm assuming you throw the pellet hops right in your conical fermenter and then let them sink... I've always used a SS canister to dry hop with - even in the Chronical - how long does it take for the pellet hops to sink to the bottom of the cone?
 
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