Thursday, September 18, 2014

How I Dry-Hop My IPAs with No Oxygen Pickup and No Clogged Kegs

It's a metaphor for society.


Since the beginning of the year, I've been alluding to a new dry-hopping procedure I devised. I've probably explained it in parts here and there, but never in great detail. Since I've gotten a number of emails about exactly what I use and how I go about it, I figured I'd do a short (editor's note: not really that short, as usual) post on the process. I've been very, very happy with the results, and it doesn't really require much extra effort, just a few more pieces of equipment to (easily) be cleaned. The only downside, potentially, is the cost, and dedicating a keg just to dry-hopping.

Here's the basic theory behind this: oxygen is very bad for hops. When I was bottling my IPAs, no matter how good the recipe or how well-managed the fermentation, they would always drop off very, very quickly. The better you can prevent O2 from infiltrating your beer, the better chance the hop character has to preserve its awesomeness. 

During fermentation and for maybe a week or so after, enough CO2 is generated that there's a protective blanket over the beer. Yeast are still cleaning up and doing their thing. Oxygen has been purged from the fermentor during what was hopefully a nice healthy fermentation. After this is when we most want to prevent oxygen pickup in our beers. A brewery can simply do a conical dump to remove trub (rather than transferring to a secondary) and can purge headspace with additional CO2 in the fermentation vessel, then transfer to whatever serving vessel they utilize, which will also have been purged of oxygen. Keeping O2 out is fairly easy with a standard brewery setup, and I wanted to emulate this process. 


1st Step - Initial Dry Hop in Primary
I add the first round of dry-hops after the end of primary fermentation, which is usually about 5 - 7 days after brewday. Enough of a CO2 blanket should be hanging around at this point that I'm not too concerned about oxygen getting in. This first stage dry-hopping is pretty standard. I let it go for about 5 days.

2nd Step - Second-Addition Dry Hop / Secondary Keg
I generally ferment my IPAs in a bucket with a spigot, because buckets fit in my fermentation fridge and carboys do not. However, this step is the one place where some oxygen could still be getting into my beers, as I'm not transferring under CO2 pressure at this stage, and the CO2 blanket over the beer in the primary vessel may be diminished by now (~12 days out from brew-day). Recently, Luke at MetaBrewing made a similar post about kegging beers without oxygen pickup — in fact, I almost scrapped this post when I saw his pop up, but upon reading, we actually have a fairly different approach which could, in fact, easily be combined. Luke's system is designed to get the beer out of the primary and into a keg under CO2 pressure, and the keg could just as well be my "dry-hopping in keg" method, carrying on with my procedure from this point. Check out Luke's post if you want to go all the way with this concept.

The end goal of this second stage is to dry-hop in a fully-sealed, CO2-purged vessel where oxygen can be banished with assurance. In other words, dry-hopping in a keg*, while still limiting the amount of time the beer is on the dry-hops. The main problem with dry-hopping in a keg is that hops tend to clog dip-tubes very, very easily. I personally find nothing in the entire homebrewing hobby more irritating than repeatedly clearing a diptube until it finally starts dispensing beer.

Here's my system.

1). Trim end of diptube (I used a dremel) about an inch to an inch and a half.




2). Slide a Corny Keg Dip-Tube Screen over the trimmed end of the dip-tube. This is short, coarser screen that fits snugly over the dip-tube. If you're using leaf hops, it may be enough on its own, but will likely clog if you throw too much mass up against it. It is probably not enough to filter out many smaller particles on its own either.

This filter can be purchased here.

3). For this reason, I use a larger, secondary filter that is open at the top but is such a fine grade (300 micron) that it will keep out all hop mass from the bottom and sides. Here's a link. I've seen this filter available from a few sources, some of them cheaper, but it can be hard to search for. I recommend digging around.

Here's the quirk behind why I went with this particular filter, though: it's actually designed to put the hops inside of it and contain them, like an expensive, durable hop bag. It's not meant to filter them out, but to act as a hop sleeve. I tried this. I did not like it for this function at all  as large as the tube is (it's almost the length of a keg, as you can see next to the dip-tube above), the hops swell and get compacted, there's not enough surface area exposure, and the extraction I got was disappointing.

However, I found that the two screens in combination, acting as a filter to keep the dip-tube clear, work brilliantly. I'm sure there are other screens (or other combinations of screens) that would also be effective — whatever is the cheapest way you can pull this off, go for it. The goal is simply to keep the dip-tube clear while at the same time giving the hops the chance to float around freely in all that beer, extracting their precious deliciousness.





3rd Step - Transfer Off Dry-Hops Into Serving Keg
After you've done the last stage of dry-hopping in your perfect O2-free keg vessel? Connect the dry-hop keg to your sanitized, CO2-flushed serving keg through the beer-out connects. Attach the CO2-connect to the gas-side of the dry-hop keg. (There will be nothing on the gas-side serving keg connect, the only connect which will be free) Crank the pressure, then open the relief valve on the serving keg until gas has pushed all the beer from the dry-hop keg into the serving keg.

You now have a lovely, aromatic IPA free from the scourge of oxygen. Hooray!

Once the beer is in the serving keg, I just keep it in the keezer and charge it normally under CO2 pressure. This is another point at which there is more room for experimentation. What about carbing, at least partially, while the beer is crash cooling before transfer out of the dry-hop keg? Or why not even rig up the gas to push in through the dip-tube of the dry-hop keg, thus both rousing the hops and carbing at the same time? This is something (the effect of CO2 on dry-hop character) that I haven't seen much information or research on, and will certainly play around with more in the future.



*Yes, you could also use this same setup to simply dry-hop in the keg you're drinking out of. I chose not to do this for two (somewhat) arbitrary reasons. One, as I mentioned, I wanted to emulate the setup and process a brewery would use. Dry-hopping in a keg sort of feels like cheating; my favorite IPA makers obviously manage to achieve their aroma and everything without taking this added measure. I wanted to know that I could, too. More practically, some brewers feel that letting a beer sit on dry-hops too long begins to extract vegetative flavors eventually. While this probably wouldn't be a big concern at fridge temps, especially considering how quickly I drink my IPAs, I decided to hold off on dry-hopping in the keg as a bonus future step rather than my default approach.

30 comments:

  1. Nice write up! Just a quick question...what if the level of the beer is above the top of the open dry hopper(which mine uually is)? Don't the hops just drop right inside it once they drop out?

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    Replies
    1. Great question. And yes, I had the same concern. Some of the hops do drop down into the tube, but it's narrow enough that it's usually not a ton. And the coarse screen plus the trimmed dip-tube is enough to prevent those from doing much damage.

      Of course, a narrower filter of the same grade would be ideal if you happen to find one! That, or drilling through the lid of this filter so that the dip-tube could just slide into it.

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  2. Nicely done!

    You posted this to finally get me off your back, didn't you? You can admit it, I would have done the same!

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  3. I just started a similar process with my IPA's. I have been bagging my hops though. I've liked the results but think it could be better. I like your double filter idea to let the hops roam around. Do you think a bazooka screen over a dip tube filter would work? I have an extra one lying around. I could probably find an o-ring to help close the end up.

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    Replies
    1. Yeah, large enough bags can work fine, but I like the flexibility of this method. A bazooka screen should definitely be able to fill at least most of this function. They're not quite as fine as the outer screen I use here so just be careful... you may still end up with some hop matter that could cause clogs!

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  4. I've been having floaty problems with my stainless dry hopper lately, tons of hop bits in suspension. I'm going to give this method a try, thanks!

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  5. did you actually have clogging issues previously with just the surescreen? am curious as I was contemplating making a change to my dryhop process similar to yours. I tested a surescreen out without cutting the diptube and used 4oz of pellets (old hops) and water, soaked for 24 hours. i did not have any issues transferring out.

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  6. Cool idea! Just curious if there would be any problems with skipping the serving keg and serving directly from the dry hop keg?

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    Replies
    1. I have friends that do that, it seems to work fine! I like transferring so it can settle some more.

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  7. In brewing there's not really such a thing as a "CO2 blanket".

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  8. Not to be a Debby-Downer, but doesn't that filter offer a ton of nucleation sites for CO2 to bubble out of your beer? Are you getting more foam?

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    Replies
    1. Well, you don't have to carb it in the dry-hop keg, though I often would. But if you're just transferring it into another keg and then letting it settle, that's not really a concern.

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    2. The best advertising is word of mouth. BOOM. Purchase made. Thanks for the recommendation!

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  9. Have you just used the dip tube filter leaving the hops in the keg the entire time the beer is dispensed?

    I too have the 300 micron filter and find the hops compact in a tight mass if more than one to two ounces. I was thinking about letting the hops soak, open the keg and dry hopper lid, and while leaving the filter submerged, stir the hops to break up the mass.

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  10. This comment has been removed by the author.

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  11. Everyone should be using the clear beer draught system, which has a float system that draws the beer from the top and eliminates the dip tube altogether. Why drink from the bottom of the keg when you can drink from the top. All the crud stays at the bottom til it kicks and the keg can be moved without having to settle. I have them for all my kegs they are about $35 each.

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  12. Is it possible to eliminate oxygen while transferring from primary to secondary fermentation bucket/carboy? Without practical experience using co2 in homebrewing, I can only imagine if purging such fermentation vessels with co2 initially and then siphoning over the beer carefully could eliminate oxygen completely from ever getting in to contact with the hop aromas of an IPA?

    Thanks for the efforts making this blog. :)

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  13. Great article. I'm wondering if one of these hop strainers for better bottles is a good option as well. Most of my kegs have the bent dip tubes and I wasn't sure if thats an issue with the filter.

    https://utahbiodieselsupply.com/brewingfilters.php#glasscarboydryhopper14

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    Replies
    1. thanks for this link! I actually bought a 2nd dip tube that is straight to use solely w/ this since you need to trim some off the bottom anyway...drilled a hole in one of the rubber stoppers to slide the dip tube through. I'll be using it in a couple weeks for the first time, but as far as assembly goes, it's great.

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  14. Thanks for this man. I read this quite a while ago, but just pulled the trigger on the items. I planning to brew a Boneyard Notorious (http://boneyardbeer.com/menu/notorious/) inspired Triple IPA and I'll be using this method for the massive dry hop. I was at the Mikkeller/Three Floyd's War Pigs brewpub in Copenhagen last summer and they has a bunch of beers on from breweries in the U.S. that came over and brewed their beers on-site. There was stuff like Alesmith Speedway Stout, Bell's Hopslam, etc, but the best beer I had all night was the Boneyard Notorious. Cheers!

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  15. Would the Better Bottle hop filter linked below work for the outer dip tube filter? It I cheaper, taller, and skinnier than the one linked. I'm thinking it may be tall enough to eliminate any hop particles from getting inside it? If the opening is above the liquid level in the dry hop keg.

    https://utahbiodieselsupply.com/brewingfilters.php#betterbottledryhopper

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    Replies
    1. Just noticed someone else recently suggested the same filter! If anyone has experience using it please let me know.

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    2. Hey Eric, I haven't used that filter, but it's the same concept and looks like it should work well!

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  16. hanks for the best blog.it was very useful for me.keep sharing such ideas in the future as well.this was actually what i was looking for,and i am glad to came here!
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  17. I've got mine together, however I have not yet trimmed the dip tube. I wanted to see if things would fit together without trimming first. I'm thinking I should still trim it up a bit to help potential clogging of the flow, is that the main purpose for trimming yours?

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  18. Very interesting. I always like hearing what other peoples' methods are (rather than pretending one size fits all). I admire the fact that you're trying to do what professionals are. Me- I'm more interested in making great beer as easily as I can. I find a nylon mesh bag, keg hopped, does exactly what I want. I've never come across negative issues with keg hopping (vegetal, grassy, or other notes). To each their own. Cheers!

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  19. One question: why use a coarser dip tube screen in conjunction with a 300 micron outer screen? In theory the 300 micron should do the job and anything that passes will fly right through the coarser dip tube screen.

    I wish the 300 micron screen was available just a touch taller (22-22.5") to maximize the amount of liquid I could fit in a keg utilizing this system. I know you can order custom, but it's a big nut as is...

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  20. I use the same SS hop filter from ArborFab, but I also use a WilserBrewer hop sock over it and secure it at the top of the SS filter with a ty-rap. Keeps pretty much everything out.

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  21. For clarity, the ty-rap is secured around the dip tube which "seals" the hopsock over the open end of the SS filter

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