Pressure Fermenting

[rojopem]

Do 5 gallon Corny Kegs, fitted with a Spunding Valve have enough head room in the keg to ferment a 5 gallon batch without gumming up the Spunding Valve?

 

[GoodTruble]

No. A 5 gallon keg filled with 5 gallons doesn't have any extra room, and will almost certainly foam into the exit disconnect. If you must fill as much as possible, you could try a blowoff tube until high krausen is over and then attach the spunding valve. But it is a lot simpler to just do 4.5 gallons (or less if you expect a lot of krausen).

 

[IslandLizard]

If you must fill as much as possible, you could try a blowoff tube until high krausen is over [...]

[...] where you could easily lose half a gallon of beer to blow-off... netting also 4.5 gallons.
I'd stick to 4.5 gallon batches. It's less messy too.

If you really need the extra 1/2-3/4 gallon, ferment it on the side in a gallon-size glass jug. Combine when packaging.

 

[mac_1103]

The obvious solution is to brew bigger batches and ferment in two kegs!

 

[Yesfan]

The obvious solution is to brew bigger batches and ferment in two kegs!

Great point. I have a 15 gallon corny I use for double batch pressure fermentations. Plenty of head space for a 10 gallon batch. I think next time, I'll just split 9 gallons to two 5 gallon cornys. I'm giving up a gallon of beer, but the trade off is not having to do a transfer to a serving keg since the fermenter is the serving keg.

 

[dallasd9]

No. A 5 gallon keg filled with 5 gallons doesn't have any extra room, and will almost certainly foam into the exit disconnect. If you must fill as much as possible, you could try a blowoff tube until high krausen is over and then attach the spunding valve. But it is a lot simpler to just do 4.5 gallons (or less if you expect a lot of krausen).

I just started a corny keg pressure fermentation with 4 gallons to provide head space during fermentation. Would it be ok to add the last gallon of water after fermentation is complete assuming the FG will be higher than planned

 

[IslandLizard]

I just started a corny keg pressure fermentation with 4 gallons to provide head space during fermentation. Would it be ok to add the last gallon of water after fermentation is complete assuming the FG will be higher than planned

Sure you can.*
But when mixing, you can't prevent your (now settled out) yeast/trub cake also getting mixed in again.

I recommend transferring the finished beer to a serving keg (leaving the yeast/trub behind) and top that one up with water to your desired gravity.* All done with closed, air- and oxygen-free transfers, of course.

* [Edits/rephrasing] Make sure your top-up water is deoxygenated, although I'm not sure how to accomplish that easily.

Needless to say, when using tap water for topping up it also needs to be dechlorinated. That can be simply done with some Campden or "K-meta" powder.

Oxygen and Chlorine ruin beer.

 

[dallasd9]

Sure you can.*
But when mixing, you can't prevent your (now settled out) yeast/trub cake also getting mixed in again.

I recommend transferring the finished beer to a serving keg (leaving the yeast/trub behind) and top that one up with water to your desired gravity.* All done with closed, air and oxygen-free transfers, of course.

* Make sure your water is deoxygenated, and also dechlorinated, using Campden (or K-meta powder), when using tap water.
Oxygen ruins beer.

Thank you for the feedback. That's exactly what I was planning on doing (closed transfer). I always use K-meta powder also. Do you think it will be a similar result if I would have fermented with the full five gallons? Or will it be watered down somewhat?

 

[IslandLizard]

Please mind, I've edited/rephrased my previous post, hoping to be a bit more clear, precise.

Do you think it will be a similar result if I would have fermented with the full five gallons? Or will it be watered down somewhat?

Common sense would expect the 2 resulting beers to be (very) similar, yes. But I have no hands-on experience with that.
Many (most) macro breweries (e.g., Budweiser) seem to do that, mixing batches and diluting at packaging.

Let us know how it turns out, we're always curious...

 

[dallasd9]

Sure you can.*
But when mixing, you can't prevent your (now settled out) yeast/trub cake also getting mixed in again.

I recommend transferring the finished beer to a serving keg (leaving the yeast/trub behind) and top that one up with water to your desired gravity.* All done with closed, air and oxygen-free transfers, of course.

* Make sure your water is deoxygenated, and also dechlorinated, using Campden (or K-meta powder), when using tap water.
Oxygen ruins beer.

Thank you for the feedback. That's exactly what I was planning on doing (closed transfer) I always use K-meta powder also. Do you think it will be a similar result if I would have fermented with the full five gallons? Or will it be watered down somewhat?

Please mind, I've edited/rephrased my previous post, hoping to be a bit more clear, precise.


Common sense would expect it to be similar, yes. But I have no hands-on experience with that.
Many (most) macro breweries (e.g., Budweiser) seem to do that, mixing batches and diluting at packaging.

Let us know how it turns out, we're always curious...

Will do. Thanks again

 

[Yesfan]

Sure you can.*
But when mixing, you can't prevent your (now settled out) yeast/trub cake also getting mixed in again.

I recommend transferring the finished beer to a serving keg (leaving the yeast/trub behind) and top that one up with water to your desired gravity.* All done with closed, air- and oxygen-free transfers, of course.

* [Edits/rephrasing] Make sure your top-up water is deoxygenated, although I'm not sure how to accomplish that easily.

Needless to say, when using tap water for topping up it also needs to be dechlorinated. That can be simply done with some Campden or "K-meta" powder.

Oxygen and Chlorine ruin beer.

What about boiling the top off water to de-oxygenate it? Maybe do that and have that water cooled (with your added k-meta powder) already in the serving keg. Then (via closed transfer), rack the beer on top to get your 5 gallons. I'm thinking it shouldn't be any different than when bottlers would rack from their carboys to a bottling bucket with primer solution at the bottom. Just spitballing here.

Personally @dallasd9 on the next go around, I'd keep it simple and just do a 4 gallon batch when fermenting in a 5 gallon keg.

 

[dallasd9]

What about boiling the top off water to de-oxygenate it? Maybe do that and have that water cooled (with your added k-meta powder) already in the serving keg. Then (via closed transfer), rack the beer on top to get your 5 gallons. I'm thinking it shouldn't be any different than when bottlers would rack from their carboys to a bottling bucket with primer solution at the bottom. Just spitballing here.

Personally @dallasd9 on the next go around, I'd keep it simple and just do a 4 gallon batch when fermenting in a 5 gallon keg.

Sounds like a good way of adding the water.

Next time if I just go with a four gallon batch would I need to reduce the the initial recipe accordingly?

 

[lumpher]

on't you hate it when you see someone in the building is stocking up on Hall

Sounds like a good way of adding the water.

Next time if I just go with a four gallon batch would I need to reduce the the initial recipe accordingly?

Yep. If you want to reduce the batch size by 20%, just use 20% less grain and hops.

 

[Yesfan]

Sounds like a good way of adding the water.

Next time if I just go with a four gallon batch would I need to reduce the the initial recipe accordingly?

Yep. Look at some brewing software like Beersmith, Brewfather, and others or do a 20% reduction of ingredients like Lumpher suggested if you don't have the software. I recommend the software as there's (obviously) other uses besides batch side adjustment.

 

[IslandLizard]

Look at some brewing software like Beersmith, Brewfather, and others or do a 20% reduction of ingredients like Lumpher suggested if you don't have the software.

In that light I also want to mention Brewer's Friend. It's always free, no signup needed.

https://www.brewersfriend.com
There's a direct link to Brewer's Friend in the top bar of our forums, named Brewing Software.

 

[dallasd9]

In that light I also want to mention Brewer's Friend. It's always free, no signup needed.

https://www.brewersfriend.com
There's a direct link to Brewer's Friend in the top bar of our forums, named Brewing Software.

Yep, already have it and use it for my all grain brews. Didn't realize it had the reducing calculator feature. Thanks