Fermenting a 5 gal Batch in a 15 gal Vessel

[TAK]

I'm considering investing in a non-standard volume corny keg for fermenting in. My first thought was to get a 10 gal corny. Right now, I only brew 5 gal batches. However, eventually I'd like to brew some 10 gal batches. So, the thought crossed my mind of getting a 15 gal corny.

Are there any reasons why it would be a bad idea, a hassle, etc., fermenting a 5 gal batch in a 15 gal vessel?

Would that be too much like open fermentation (flavor wise), due to the headspace?

One of the reasons for fermenting in a corny is to have a completely closed system, from fermenting to the serving keg. But would a 5 gal fermentation produce enough CO2 to purge 9.5-10 gal of headspace?

 

[Chrisl77]

If you are concerned about o2 in the head space you could purge the keg with co2 before you fill it.

 

[sikkingj]

Where did you find 15 gallon cornies, I'm interested in doing the same sort of thing (I'll use a blow off tube though).


Sent from the window of an airplane...

 

[DoWBrewer]

I regularly brew 5-gallon batches in my 16-gallon Spiedel fermenter. I have not noticed a difference vs. carboys. I pretty sure that the CO2 from fermentation quickly pushes the residual air out. I think you are safe.

 

[ruger988]

Where did you find 15 gallon cornies, I'm interested in doing the same sort of thing (I'll use a blow off tube though).


Sent from the window of an airplane...

Easy to find new with a quick google search. New usually means $250+ though.

 

[Silentdrinker]

You wouldn't need to purge the oxygen out, you will get PLENTY a of co2 produced and blown out of your spunding valve or blow off tube.

It would work fine, but your biggest issue is temp controlling. Those 15 gal corny kegs are pretty tall. So you'll have to do your chamber accordingly.

Sometimes you can find "seconds" for cheaper. They're factory rejects. Just keep in mind that they may NOT be usable for fermenting because they could have welding issues that will be virtually impossible to get Sanatized. The websites that sell them don't always mention this. And often they are factory direct sold as is, so be careful.

However, fermenting this way is hands down the best method, in my opinion. I have 10 gal kegs I ferment in. I would simply split my batches. Now I'm selling those off because I'm using 15.5 gallon corny kegs that I built from decommissioned sanke kegs to ferment full 12 gallon batches.

 

[TAK]

Ya, you can easily find them via google. I also found mention that the refurbed ones can be unusable.

I'm actually leaning back towards a 10 gal. The 15 gal are obviously of a wider circumference, and I think they wouldn't be well suited to upward temp control on a comparatively small 5 gal batch.

 

[Silentdrinker]

Ya, you can easily find them via google. I also found mention that the refurbed ones can be unusable.

I'm actually leaning back towards a 10 gal. The 15 gal are obviously of a wider circumference, and I think they wouldn't be well suited to upward temp control on a comparatively small 5 gal batch.

I think they're the same circumference just taller than the 10 gal. My 13 and 10s are. 13 is slightly taller way heavier (thicker ss) and has 4 ports. I ferment up to 7gal in my 10s.

If you find a deal, you may be able to get two 10s for one 15. Then you can split batches. You just have to look hard for really good deals. I have 7. I got 3 of mine on Craig's list, and 4 I bought off eBay as portable eyewash stations. I averaged $100/ea total between all parts and shipping. The portable eyewash stations were brand new in the box. They just needed the posts. The Craig's list ones all seemed brand new too. All 7 are the exact same Firestone tank.

 

[quaboagbrewing]

I regularly brew 5-gallon batches in my 16-gallon Spiedel fermenter. I have not noticed a difference vs. carboys. I pretty sure that the CO2 from fermentation quickly pushes the residual air out. I think you are safe.

I got the 60L Spiedel fermenter anticipating starting to brew larger batches but for my setup 5 gallon batches have just made more sense so I have not used my Spiedel yet. I am about to brew a 5 gallon DIPA and figured I'd try fermenting in the Spiedel. Curious if you are draining using the spigot on the Spiedel or siphoning out? I did a test drain from the spigot and 1.3 gallons of water was left behind. Even if I factor in a good amount of trub seems like that's a lot of beer left behind. Wondering how you deal with that. I really want to use this baby as it will be so much nice then my carboys for primary. No need for fermcap or blowoff.

 

[DoWBrewer]

I use the spigot, but I prop up the back of the fermenter so it is leaning towards the spigot. I find that I don't leave much behind. It is important to prop it up and then let it settle for about ten minutes before bottling or kegging.