Author Topic: Fermenting in a 7.9 Gallon Primary  (Read 1141 times)

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Fermenting in a 7.9 Gallon Primary
« on: February 22, 2012, 08:55:47 AM »
Fellow Brewers,

I've decided to try my hand at brewing 7.5 gallon batches and kegging in the new slim quarter kegs.  However I obviously cannot fill a 7.9 gallon primary with 7.5 gallons of wort and not expect something to blow up or at the very least have half my yeast go through the blow-off tube.

How much headspace would you recommend in the 7.9 gallon fermenter?  I was thinking about brewing 6 gallons to a higher OG and adding a gallon of water when I keg.  Thoughts?

Dave
Dave Zach

Offline tschmidlin

  • I must live here
  • **********
  • Posts: 8130
  • Redmond, WA
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #1 on: February 22, 2012, 10:07:16 AM »
I would brew 6 gallons and just put that in the keg, or brew more and use fermcap.  I would not dilute it with water.
Tom Schmidlin

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #2 on: February 22, 2012, 10:23:14 AM »
I would brew 6 gallons and just put that in the keg, or brew more and use fermcap.  I would not dilute it with water.

Curious as to why not add water? 
Dave Zach

Offline nateo

  • Brewmaster General
  • *******
  • Posts: 2162
  • Aachen, DE
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #3 on: February 22, 2012, 10:30:15 AM »
I've diluted with water post-ferment without issues. Usually I do this when I overshoot my OG on brew day, and don't have time to sterilize top-off water right then.
In der Kürze liegt die Würze.

Offline tom

  • Senior Brewmaster
  • ******
  • Posts: 1110
  • Denver, CO
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #4 on: February 22, 2012, 10:50:55 AM »
If you do add water post-fermentation I would add sanitary, de-aerated water.  (Boil and let cool.)
Brew on

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #5 on: February 22, 2012, 10:52:47 AM »
If you do add water post-fermentation I would add sanitary, de-aerated water.  (Boil and let cool.)

Thanks.  That's a great point.  I didn't even think that the water would be oxygenated coming out of the faucet.......
Dave Zach

Offline tschmidlin

  • I must live here
  • **********
  • Posts: 8130
  • Redmond, WA
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #6 on: February 22, 2012, 11:23:22 AM »
I would brew 6 gallons and just put that in the keg, or brew more and use fermcap.  I would not dilute it with water.

Curious as to why not add water? 
Mostly because I formulate recipes for a non-diluted batch, going more concentrated will have some effects on hop utilization and fermentation profile.  If you want to play around with it that's cool, it's just not what I would do.
Tom Schmidlin

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #7 on: February 22, 2012, 12:33:39 PM »
Tom,

I see your point.  Do you think I could get away with 7 gallons and just let the Krausen blow out?  Or do you think that would be detrimental to the beer?

Dave
Dave Zach

Offline tschmidlin

  • I must live here
  • **********
  • Posts: 8130
  • Redmond, WA
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #8 on: February 22, 2012, 12:40:16 PM »
Letting it blow out is fine, but you might lose more than you want to with a really full fermenter.  You can always build an expansion chamber for your fermenter too :)  Think of it like a sanitized funnel that you stick in the neck of a carboy and cover with foil - it will give room for the krauzen to form, but it will drain back into the carboy so you don't lose as much.
Tom Schmidlin

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Re: Fermenting in a 7.9 Gallon Primary
« Reply #9 on: February 22, 2012, 12:42:30 PM »
VERY cool idea man!   ;)

I may have to play with that one....
Dave Zach