Author Topic: My latest effort to eliminate oxidation  (Read 725 times)

Offline yso191

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My latest effort to eliminate oxidation
« on: September 10, 2015, 03:49:53 AM »
This thread: https://www.homebrewersassociation.org/forum/index.php?topic=23951.0

Got me to thinking about a project idea I had and spurred me on to complete it.  Specifically, I want to avoid introducing oxygen in my beer when I dry-hop.  Below is a picture of the completed project.  It is simply a stainless steel water bottle I bought from Ace.  I had my son-in-law drill a hole and weld a threaded nipple into the bottom.  I then screwed a gas post onto the nipple. 

The idea is to put my dry-hop hops into the bottle, cover the opening with a small, thin piece of sheet metal, then connect CO2 and purge the air out of the bottle.  I will then invert the bottle over the opening of my fermenter and slide the sheet metal out, allowing the pellets to drop.

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Offline kbenton00

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Re: My latest effort to eliminate oxidation
« Reply #1 on: September 11, 2015, 04:35:35 PM »
Just a thought... but since CO2 is heavier than air can't you simply put the hops in the container, insert a CO2 purge line in the top, and then let the container fill with CO2?  After a few seconds of CO2 purge all the air should be displaced in the container and then you can pour the hops into fermenter.

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Offline Werks21

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Re: My latest effort to eliminate oxidation
« Reply #2 on: September 11, 2015, 06:03:15 PM »
Just a thought... but since CO2 is heavier than air can't you simply put the hops in the container, insert a CO2 purge line in the top, and then let the container fill with CO2?  After a few seconds of C02 purge all the air should be displaced in the container and then you can pour the hops into fermenter.

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you could do that.. however this seems to be a more thorough purge because the CO2 is displacing from the bottom up. I have theorized that you could get a complete purge in just about any vessel but it would involve several steps including shaking and  multiple purges as well as allowing the Co2 to settle between steps. We all pick our battles...
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Offline kylekohlmorgen

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Re: My latest effort to eliminate oxidation
« Reply #3 on: September 11, 2015, 06:27:18 PM »
I think this is a good start, but I don't see how it reduces oxygen pickup vs. just dumping hops into the keg.

The container is not under pressure, so its less of a 'purge' and more of a blow out with CO2. You will absolutely reduce some O2 in the container, but considerably less than with a pressurized purge.

With CO2 purges, you are mixing the CO2 with air, diluting the O2 concentration. In a keg, hop cannon, or other pressure vessel, you can increase the vessel pressure with CO2, proportionally decreasing the concentration of O2. In a non-pressurized container, you're pretty much relying on displacement by gas flow through it, meaning you're using a LOT of CO2 to mechanically displace some air. Because its not sealed, oxygen quickly flows back in after air flow stops to regain equilibrium inside and outside of the container.

I also think you might inadvertently blow a bunch of hop dust everywhere.

You might have better luck displacing O2 with a heavy inert gas like Argon. Since your SiL is a welder, he might be able to help you out here :). Still, the inversion of the unsealed container will inevitably force the heavy gas out and the light gas in.

Better still is to add the hops to a purged and empty keg, purge it a few times after adding hops, then transfer the beer on top from another keg. I think this method tops all others in terms of O2 reduction, including the 'hop cannon' used by several pro breweries. Pro brewers can't do it this way because they need hops to distribute throughout their tall vessels. Our surface area/volume ratio is much larger, and if you want more you can just tip the keg over.

If you want to keep plugging away with the mini-hop-cannon project, I'm sure we could think of some ways to install it into a closed, purge-able location. We'd have to call it  a 'hop-sparkler' or something, though. (Trademark/patent pending)

Sorry for the long-winded answer and half-science babble. I've had some free time at work lately  :o
« Last Edit: September 11, 2015, 06:41:33 PM by kylekohlmorgen »
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Offline blatz

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Re: My latest effort to eliminate oxidation
« Reply #4 on: September 11, 2015, 06:30:43 PM »
pretty sweet rig.

i dryhop in kegs (sure screen attached to diptube).  i started dumping in hops and then purging from the bottom with CO2 (use a liquid QD on your CO2 tank).  I haven't started to yet, but you *could* do a closed transfer into the keg at that point by racking into the keg via the dip tube. 

probably gets you to the same point, and of course, the OP is trying to dryhop in the fermentor which presents its own set of challenges.
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Offline brewinhard

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Re: My latest effort to eliminate oxidation
« Reply #5 on: September 11, 2015, 10:54:10 PM »


i dryhop in kegs (sure screen attached to diptube).  i started dumping in hops and then purging from the bottom

Are you using pellets with this method?  If so, don't they clog the sure screen after they settle out?

Offline blatz

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Re: My latest effort to eliminate oxidation
« Reply #6 on: September 11, 2015, 11:09:26 PM »


i dryhop in kegs (sure screen attached to diptube).  i started dumping in hops and then purging from the bottom

Are you using pellets with this method?  If so, don't they clog the sure screen after they settle out?

I am talking about pellets - never had a problem, even up to 5 oz
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