Fermenting in a corny keg?

[BongoYodeler]

People here have posted the math related to the amount of CO2 created in a fermentation and it seems plenty sufficient to purge 2 kegs. I often have 2 kegs(dry hop keg, serving keg) daisy chained to my ferm keg to be purged and it seems to work fine

This is exactly what I plan to do. Thanks.

 

[BongoYodeler]

How do you dry hop in this case? Isn't the intent to have an O2 free sanitized keg? How do you get the hops in?

Here's my thought. 3 kegs daisy-chained. Keg1 is the fermenter. Keg2 is the dry hop keg. Keg3 is the serving keg, with a blowoff.

Keg2 will have a floating dip tube, and I'll start with no hops in it. Once fermentation really gets going, as evidenced by increased blowoff activity, I'll quickly open the lid of keg2 and dump in the hops, loose. I figure most/all oxygen that enters while the lid is off will rather quickly be pushed out by the continued fermentation. They'll then sit in a CO2 environment until it's time to dry hop.

After fermentation is over I can disconnect the chain and throw keg1 into my keezer to cold crash. After cold crashing for a couple days I can transfer the beer to keg2 at 37° and keep it at that temperature, shaking the keg every few hours to help keep the hops in solution. Or pull the keg from the keezer and transfer to keg2 a bit warmer and not need to shake it.

After a 2-3 day dry hop, transfer to keg3 via floating dip tube hopefully avoiding hop debris. All transfers will be done under pressure, oxygen free.

 

[BongoYodeler]

Lots of good reading on this thread and perfect timing as I have been thinking of doing this and ditching my buckets and all the other crud I bought with my starter kit (my brother is getting into it so I might just give it to him with a small delivery fee, LOL). My question is, I have a 5 gallon Torpedo keg and I do 5 gallon batches. Usually what ends up in the fermenter is about 5 gallons, so what, if any, cautions do I have to have when fermenting? I have read some have had some blow off issues, but the kegs will be in a closet that is easily cleaned. If I am going to run a Spunding valve and try to catch the CO2 from the fermentation how would I get the Ferm CO2 from the fermenting keg to the serving keg? This is all very new to me, but seems to be a nice way to ditch a lot of extra equipment and make better beers.

I'm going to shoot for 4.5 gallons into the keg fermenter.

Connect the gas-in port on your fermenting keg to the beer-out port on your serving keg. Connect the gas-in port on your serving keg to either a spunding valve or some tubing going to a jar of water/StarSan.

I bought some Ferm Cap to add to the fermentation keg to help keep the krausen down. But I've never done this before so I'm not sure of the best time to add it. Hopefully someone will chime in.

 

[doug293cz]

Keg2 will have a floating dip tube, and I'll start with no hops in it. Once fermentation really gets going, as evidenced by increased blowoff activity, I'll quickly open the lid of keg2 and dump in the hops, loose. I figure most/all oxygen that enters while the lid is off will rather quickly be pushed out by the continued fermentation. They'll then sit in a CO2 environment until it's time to dry hop.

I would put the hops in the 2nd keg at the very beginning. CO2 production is highest early in the fermentation cycle. If you wait until you have "increased blowoff activity," as much as 1/3 - 1/2 of the CO2 may have been created already. You will then undo a lot of the purge "work" already done by adding significant O2 to the system (by opening one of the lids), and not have sufficient CO2 production after that to adequately finish the purging. It might be OK, or it might not.

Brew on

 

[BongoYodeler]

I would put the hops in the 2nd keg at the very beginning. CO2 production is highest early in the fermentation cycle. If you wait until you have "increased blowoff activity," as much as 1/3 - 1/2 of the CO2 may have been created already. You will then undo a lot of the purge "work" already done by adding significant O2 to the system (by opening one of the lids), and not have sufficient CO2 production after that to adequately finish the purging. It might be OK, or it might not.

Brew on

Thanks Doug, I'll do that. My intent was to limit the hops from sitting in an oxygen-rich environment for as long as possible. Hopefully the few hours it would take for fermentation to kick off won't be too long for them.

Also, I looked at your post, referenced above, on CO2 displacement. I have to admit it made my eyes glaze over But it looks like enough CO2 is created to fill two 5 gallon corny kegs, while (hopefully) displacing all the oxygen.

 

[Adam Zerwick]

Thanks Doug, I'll do that. My intent was to limit the hops from sitting in an oxygen-rich environment for as long as possible. Hopefully the few hours it would take for fermentation to kick off won't be too long for them.

Also, I looked at your post, referenced above, on CO2 displacement. I have to admit it made my eyes glaze over But it looks like enough CO2 is created to fill two 5 gallon corny kegs, while (hopefully) displacing all the oxygen.

I wonder if it would be any better to purge the empty dry hop and serving kegs in parallel instead of serially. My guess is that it would take less fermentation CO2 to purge both kegs when done in parallel but that's just a hunch.

 

[BongoYodeler]

I wonder if it would be any better to purge the empty dry hop and serving kegs in parallel instead of serially. My guess is that it would take less fermentation CO2 to purge both kegs when done in parallel but that's just a hunch.

Well darn it, now something else to consider. This could set me back another three years. LOL!!

 

[RyPA]

Lots of good reading on this thread and perfect timing as I have been thinking of doing this and ditching my buckets and all the other crud I bought with my starter kit (my brother is getting into it so I might just give it to him with a small delivery fee, LOL). My question is, I have a 5 gallon Torpedo keg and I do 5 gallon batches. Usually what ends up in the fermenter is about 5 gallons, so what, if any, cautions do I have to have when fermenting? I have read some have had some blow off issues, but the kegs will be in a closet that is easily cleaned. If I am going to run a Spunding valve and try to catch the CO2 from the fermentation how would I get the Ferm CO2 from the fermenting keg to the serving keg? This is all very new to me, but seems to be a nice way to ditch a lot of extra equipment and make better beers.

I don't think you have any cautions, just use a blow off tube in a pitcher/bowl of sanitizer. I use a 6.5g Torpedo and fill it to probably a little over 6g. There's should be no risk of an exploding keg if that's what you're concerned with, as the force needed to explode a keg would easily clear out a clogged up ball lock fitting that may have crap in it. Once you try it you won't go back.

Here's my thought. 3 kegs daisy-chained. Keg1 is the fermenter. Keg2 is the dry hop keg. Keg3 is the serving keg, with a blowoff.

Keg2 will have a floating dip tube, and I'll start with no hops in it. Once fermentation really gets going, as evidenced by increased blowoff activity, I'll quickly open the lid of keg2 and dump in the hops, loose. I figure most/all oxygen that enters while the lid is off will rather quickly be pushed out by the continued fermentation. They'll then sit in a CO2 environment until it's time to dry hop.

After fermentation is over I can disconnect the chain and throw keg1 into my keezer to cold crash. After cold crashing for a couple days I can transfer the beer to keg2 at 37° and keep it at that temperature, shaking the keg every few hours to help keep the hops in solution. Or pull the keg from the keezer and transfer to keg2 a bit warmer and not need to shake it.

After a 2-3 day dry hop, transfer to keg3 via floating dip tube hopefully avoiding hop debris. All transfers will be done under pressure, oxygen free.

Just my opinion, but all of the work involved with daisy chaining when you have to crack open the keg anyway to dry hop seems to defeat the purpose. I did a few NEIPA's earlier this year using this purging with fermentation gas method and I didn't see a noticeable difference compared to keg fermenting (which also purges out all o2) and then quickly popping the lid to drop hops in then doing 10 or so co2 purges. My NEIPA's taste better than they ever have and look like OJ until they kick.

Here's what I have on tap now

 

[Adam Zerwick]

Well darn it, now something else to consider. This could set me back another three years. LOL!!

Here's my current process for fermentation keg + dry hop keg + serving keg:

1) Ferment as normal with fermentation keg blowing off into bucket of starsan until the headspace in fermentation keg is at target O2 level. I created a spreadsheet to help me calculate the gravity at which this happens... I think the calculator is shared in the other thread. The assumption is that O2 in headspace doesn't get consumed by yeast.

2) Once I reach this target gravity I'll connect ferm. keg to dry hop keg (gas post to gas post). The dry hop keg is filled to the brim with sanitizer and has floating dip tube with filter. The dry hop keg is connected to serving keg (liquid to liquid post).

3) Once all sanitizer is pushed into serving keg I'll disconnect dry hop keg. Then connect ferm. keg to serving keg (gas post to gas post) and have liquid post go into liquid post of a storage keg or a bucket.

4) Once fermentation is complete, soft/cold crash.

5) Gravity closed transfer fermentation keg to dry hop keg. Usually I'll have enough gravity points left after liquid purge to build up pressure in the kegs.

6) Open dry hop keg lid and toss dry hops and some metabisulfite (0.1 g) into beer. Purge a few times. My thinking here is there is minimal headspace since the dry hop keg is full of beer... so any oxygen in there can be purged more efficiently and has less drastic effect than opening up an empty keg to throw dry hops into.

7) Rouse a few times a day for couple of days by rolling the keg around.

8) Cold crash dry hop keg for 1-2 days

9) Transfer to serving keg


I'd really like to avoid opening up the dry hop keg but haven't figured out an elegant way of doing this with my setup and volumes.

 

[BongoYodeler]

Just my opinion, but all of the work involved with daisy chaining when you have to crack open the keg anyway to dry hop seems to defeat the purpose. I did a few NEIPA's earlier this year using this purging with fermentation gas method and I didn't see a noticeable difference compared to keg fermenting (which also purges out all o2) and then quickly popping the lid to drop hops in then doing 10 or so co2 purges. My NEIPA's taste better than they ever have and look like OJ until they kick.

Here's what I have on tap now
View attachment 806854 View attachment 806855

Great looking beers!!

As I said, this is an experiment. Doing this with an APA as proof of concept, with eventual plans of trying it with a neipa. Here's a neipa I brewed a couple years ago..and it turned out quite good. I'm just looking for process improvements and a simpler method.

But as far as "all that work," I just don't see it. The purge lines are all assembled. With MFL QD's, Duotight fittings, and EVABarrier tubing it took all of a minute or two to put them together. I have the extra kegs. Per my normal process they're already cleaned and sitting half filled with StarSan, ready to go. This setup will be much faster and easier than my normal routine of fermenting in my Speidel fermenter, which has its own cold crashing issues, and having to dry hop with magnets. All doable but I'm looking for something with less variables.

 

[redrocker652002]

Just a thought as I am sitting here at work. How would you check gravity during the fermentation to see if it has completed? The reason for doing this is to keep the O2 out, but to check the gravity the only way I can see doing it is opening the lid of the fermenting keg and grab some beer out. I really am thinking of doing this, but wondering about that one issue.

 

[McMullan]

How would you check gravity during the fermentation to see if it has completed?

As it's under pressure, you simply pour a sample. It's usually quite foamy so the sample needs to settle and, ideally, decarbonate. No need to open the lid.

 

[doug293cz]

Just a thought as I am sitting here at work. How would you check gravity during the fermentation to see if it has completed? The reason for doing this is to keep the O2 out, but to check the gravity the only way I can see doing it is opening the lid of the fermenting keg and grab some beer out. I really am thinking of doing this, but wondering about that one issue.

You do have a beer out post on the keg you can use to pull a sample. Or, you can use one of the tilting, in-situ, hydrometers.

Brew on

 

[redrocker652002]

As it's under pressure, you simply pour a sample. It's usually quite foamy so the sample needs to settle and, ideally, decarbonate. No need to open the lid.

But it is a closed transfer setup, or do i have an additional line available with a picnic tap or something? Sorry, I am not understanding how I would just pour a sample

https://www.morebeer.com/products/b...MIuJbvwM3k-wIVwR6tBh0elQwiEAQYAiABEgJrsfD_BwE

 

[redrocker652002]

You do have a beer out post on the keg you can use to pull a sample. Or, you can use one of the tilting, in-situ, hydrometers.

Brew on

So I would need to have another line set up and connect it to the liquid line out? I was thinking that would be how, but wasn't sure.

 

[McMullan]

Yes, connect a picnic tap to the liquid-out post and pour off a sample.

 

[RyPA]

Get a rapt pill