Fermentor Headspace

Discussion in 'General Brewing Discussions' started by jmcnamara, Jun 7, 2016.

  1. jmcnamara

    jmcnamara Well-Known Member

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    i know you want as little as possible to keep oxygen contact to a minimum.

    However, my smaller batches are about 3 gallons or so. I've got the small 2 gallon buckets and 5 gallon buckets and carboys. I've been splitting the batch into 2 small buckets and splitting the yeast.

    Nosybear had recommended using plastic wrap on top of wort when kettle souring to keep oxygen away.

    I'm wondering if I could do something similar to fermenting beer in a 5 gallon bucket. would this be a cheap solution or a bad idea?

    obviously this isn't ideal, and a CO2 canister would be better. or i could just get a 3 gallon bucket.
     
  2. oliver

    oliver Well-Known Member

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    i use Mr. Beer little brown keg, which is about 3 up to the lid (zero no headspace), but it takes 2.5 perfectly. the lid doesn't have an airlock, but little notches that the CO2 escapes, never had an oxygen problem with it. not trying to mess with your process if you're doing 3 gallon batches, but i love the LBK fermenters, if you're willing to step down a half gallon for smaller batches.

    this says 2, but i put 2.5 in every other week. http://www.mrbeer.com/accessories/lbk-fermenter
     
  3. jmcnamara

    jmcnamara Well-Known Member

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    no worries, i'm taking all suggestions into consideration :D

    I'm not necessarily tied to 3 gallons specifically, but that extra half gallon is a big deal when i give out some bottles of a small run batch.

    ideally, i'd like to do it without spending too much money or being like that scene from die hard with a vengeance
     
  4. bilhelm96

    bilhelm96 Member

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    I use a 5 gallon carboy for my 3 gallon batches with no issues. If you are using a wheat beer yeast you should probably have extra room anyway.
     
  5. jmcnamara

    jmcnamara Well-Known Member

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    Just so I'm clear, you don't use any co2 to purge the headspace for the 3 gallons batches?
     
  6. J A

    J A Well-Known Member

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    Active fermentation produces enough CO2 to blanket the beer and fill the bucket, even with a lot of headspace. Just get a food-safe bucket from Walmart for a primary. Or better yet, just use the carboy and skip the secondary. It's almost never really necessary.
    And I'll add an endorsement for the Mr. Beer fermenters. For that size batch, they're really handy. You have to disassemble the spigots for cleaning which can be a pain in the butt. Other than that, they're extremely easy to use and very effective. If you''re using plastic anyway, it's a good way to go.
     
  7. J A

    J A Well-Known Member

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    You only really need to purge after fermentation. Some brewers will do it going from primary to secondary, but I think it's generally assumed that there's enough CO2 in the beer that it get's agitated and released to keep oxygen away from the beer's surface as it's being filled and then the last bit of fermentation activity will produce more CO2 to keep it blanketed during secondary/bulk aging.
     
  8. artbreu

    artbreu Member

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    Fermentation is better in larger batches, so splitting is not ideal. Go with the 5 gallon. Use whatever method best prevents disturbing the beer if your worried about oxidation.

    During fermentation there is sufficient CO2 in solution to mitigate much of the damage as long as it's not released by sloshing and even then it will rebuild and the yeast activity will clean up the damage to some degree. Post-fermentation, as CO2 levels fall off, I would look to move it down the pipeline sooner rather than later.
     
  9. bilhelm96

    bilhelm96 Member

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    No. As was said above, fermentation creates enough CO2 to fill in the headspace and since CO2 is heavier than air it will cover and protect the beer unless you move the fermenter. I don't secondary either so everything is kept pretty safe.
     
  10. wolfie7873

    wolfie7873 Member

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    I do all "half" sized batches. My kegs are 2.5 gallons, and it keeps a wider variety and keeps me brewing more often than if I had 5 gallons of everything sitting around.

    I primary in a 5 gallon and secondary in a 3 gallon. As has been said before, the head space in a primary is practically meaningless. The C02 produced during fermentation purges the vessel. (How else does it get to the airlock? :) ) Then I go with as "full" of a secondary as I can.

    I did recently go the extra mile, and add a quick disconnect to my second regulator and put an airgun attachment on the end of my gas line so I can purge stuff. I've been getting some slight oxidation flavors and think it's picking up during transfer.
     
  11. jmcnamara

    jmcnamara Well-Known Member

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    thanks everyone

    and wolfie, defintiely agree with the smaller batches for more brewing sessions. also helps me to test out new ingredients and compare the impacts of changing things more easily
     
  12. Nosybear

    Nosybear Well-Known Member

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    The only time I do a CO2 purge of anything is white wines. Primary fermentation produces enough CO2 to blow any oxygen that might be present out the airlock, no problem there. Secondary "fermentation" doesn't produce CO2 but the beer is saturated with it so you won't get any oxygen into solution. It will blanket itself with gas as the temperature changes. Lagering, where you chill the beer from its saturated state, increases the solubility of gas in beer so the beer might take up some oxygen but it will be so cold that oxidation will not happen. If you bottle condition, the yeast will scavenge any oxygen in the beer or head space and beer itself has some antioxidant properties. Blanketing will never hurt but it might not help, particularly if you bottle-condition beers.
     

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