Primary in a Corny - how much headspace?

Discussion in 'Homebrewing' started by pweis909, Oct 19, 2018.

  1. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    Over the last couple years I’ve picked up a few 2.5 and 3 gallon kegs to better accommodate small batches. Just had the bright idea of using drilled lids with air locks (purchased) with my 5 gallon kegs to brew these small batches. Would there be enough headspace?
     
  2. VikeMan

    VikeMan Meyvn (1,462) Jul 12, 2009 Pennsylvania

    3 gallon batch in a 3 gallon keg? I don't think so. A 2.5 gallon batch in a 3 gallon keg would be tight, but probably possible with low temperature, low gravity fermentations. Might be a good time to try Fermcap-S. (I haven't used it, but people say it's the tits.)
     
  3. minderbender

    minderbender Initiate (185) Jan 18, 2009 New York

    I think he's saying he will ferment in 5 gallon kegs and then package in one of the smaller kegs.

    [edited for clarity]
     
    pweis909 likes this.
  4. VikeMan

    VikeMan Meyvn (1,462) Jul 12, 2009 Pennsylvania

    In that case, then yeah, there's more than enough headspace for 2.5 or 3 gallon batches.
     
    pweis909 likes this.
  5. minderbender

    minderbender Initiate (185) Jan 18, 2009 New York

    Yeah I think so too. Except for maybe like a hefe, where the yeast sometimes goes crazy.
     
    pweis909 likes this.
  6. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    With Fermcap-S, I could do 3 gallons in my 2.5 gallon kegs!

    Yeah @mindbender had it right. Use the 5 gallon kegs to ferment the smaller batches, and then transfer to the smaller kegs. The idea was to open up the door to lower oxygen exposure via keg to keg transfer, potentially. I typically have 2 gallons head space in my other fermenters and was trying to decide if the geometry (narrower diameter) should have some impact on blow off, even though the headspace volume would be about the same. I couldn't really convince myself why it should but figured I'd ask around.
     
  7. GreenKrusty101

    GreenKrusty101 Crusader (712) Dec 4, 2008 Nevada

    Fermenting in kegs (any size) sounds like a bad idea on the surface due to cleaning issues (much like plate chillers)...convince me it's not :rolling_eyes:
     
  8. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    Could be. It's not like I'm blazing a trail though. Since I couldn't get my arm in to wipe one down, cleaning would rely more on chemical action, water pressure, and maybe something like this: https://www.amazon.com/Keg-Wand/dp/B01KK0XMLS

    Currently using chemical action and water pressure to clean kegs anyhow, so maybe it'd go fine.
     
    GreenKrusty101 likes this.
  9. thebriansmaude

    thebriansmaude Initiate (56) Dec 16, 2016 Alberta (Canada)
    Trader

    I ferment lagers in a five gallon keg with a dip tube I bent so it points horizontally about 0.5 gal above the bottom. I only use it for lagers because of headspace concerns, but I can usually package close to 4.5 gal because the krausen fits so nicely between the 5 gal marker and the lid.

    It’s great because you can just cap it by throwing the gas post on , then pressure transfer with a jumper to serving keg.

    Cleaning isn’t bad, just do it right away and give it an inverted soak in pbw in a bucket.

    With ales, I’d give it way more headspace though..
     
    GreenKrusty101 likes this.
  10. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    I gather the bend is to help avoid trub. Is there a reason you decided not to cut the tube short instead of bending it? I wasn't thinking about either of these, but makes a lot of sense.
     
    thebriansmaude likes this.
  11. thebriansmaude

    thebriansmaude Initiate (56) Dec 16, 2016 Alberta (Canada)
    Trader

    @pweis909 - Yep, I bent it just in case I decided I might want to bend it back. I also thought it might pull clearer beer if pointed slightly upwards, but this proved extremely difficult with just a spring pipe bender.

    The other thing to note is that if you bend the dip tube, you have to keep checking you can still curl it in through the liquid post as you go , for obvious reasons... so there is a limit to how much 'bend' you can get into it...
     
    pweis909 likes this.
  12. thebriansmaude

    thebriansmaude Initiate (56) Dec 16, 2016 Alberta (Canada)
    Trader

    I should add, I think fermenting in a 5 gal corny for 3 gal batches is an excellent idea, you can cold crash without worrying about suck back, you can pressure transfer with ease. Hope it works out for you.
     
    pweis909 likes this.
  13. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    Not sure that I'll get around to playing with this keg primary idea anytime soon, but I appreciate the encouragement. So many things to explore in this bruniverse and so little time.

    Yep, I said "bruniverse."
    TM
     
    Witherby and thebriansmaude like this.
  14. fuzzbalz

    fuzzbalz Disciple (313) Apr 13, 2002 Georgia

    I use a 3 gal keg to brew 2.5 gals batches, I cut the dip tube (guessed at it), and usually only get about 4-10oz of trub out when I go to press transfer to serving keg. I also us a spunding valve during fermentation. Clean up is about the same as with serving kegs, pbw soak and rinse.
     
    pweis909 likes this.
  15. dmtaylor

    dmtaylor Initiate (199) Dec 30, 2003 Wisconsin

    If I had a corny, I might use it as a fermenter. Just today I ordered two 24" tall glass vases as new fermenters, 6" diameter for 2-gallon batches, and 4" diameter for 1-gallon. I have a theory that lack of depth has been reason why most of my recent batches all taste bland and oxidized compared to past batches when I was making 2.5 to 3 gallons. I've eliminated many other variables including water source, yeast, hot and cold side oxidation. I think I might just need tall narrow fermenters to put more pressure on the yeast and limit exposure to oxygen (less surface area on top). But anyway.... somewhat related, but also I digress.

    Cheers all.
     
  16. VikeMan

    VikeMan Meyvn (1,462) Jul 12, 2009 Pennsylvania

    Hmm.
     
  17. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    IIRC, higher pressure suppresses ester formation. Or do I have that backwards. I was thinking this is why the Yorkshire squares were revered (shallow, more esters) and why the Belgian monks were reluctant to go cylindrical-conical. In any event, I thought this was something relevant to commercial brewers but not really something I'd expect to carry much importance at the small batch scale.
     
  18. dmtaylor

    dmtaylor Initiate (199) Dec 30, 2003 Wisconsin

    I think you're right, pressure suppresses esters. As to whether it's unimportant at a homebrew scale, that is exactly what I intend to find out, not guessing but to KNOW with CERTAINTY. I might be wrong. But... I might be right.
     
    pweis909 likes this.
  19. pweis909

    pweis909 Poo-Bah (1,748) Aug 13, 2005 Wisconsin
    Premium

    You suggested correcting a lack of depth. I would have thought encouraging esters would be part of the solution.
     
  20. dmtaylor

    dmtaylor Initiate (199) Dec 30, 2003 Wisconsin

    I was referring to physical depth -- the height of the beer in the fermenter. My hypothesis has more to do with oxygen ingress and less to do with pressure and esters, though I confess I really don't know what exactly to expect from a side-by-side blind tasting (which yes I do intend to do). My hypothesis is basically that when I'm using a 3-gallon carboy to ferment a 1- or 1.5-gallon batch, and it's only like 5-7 inches deep and 8 inches wide, there's a lot of surface area and not much depth for diffusion or absorption of any oxygen from any source (post-racking to bottling bucket especially) into the beer which might cause maximum oxidation compared to almost anyone else on the planet making 5 or more gallons where the oxygen might be diffused or absorbed down a few inches into the beer but unlikely down the full 15-20 inches depth of the beer, and certainly nothing like commercial breweries that are many feet deep where I'll bet there's like zero oxygen below the first foot or two of beer at the top of the fermenter.

    I'm probably nuts, and I don't blame anyone for thinking so. But I'll soon have some answers to my own questions and ponderings and will satisfy my own curiosity. And scientific experiments involving beer are fun anyway.
     
    pweis909 and frozyn like this.
  21. frozyn

    frozyn Zealot (570) May 16, 2015 New York
    Premium Trader

    I for one am curious as to what you find out with your experiment. If you don't end up making a post about it, would love to hear more one day.
     
    dmtaylor likes this.
  22. minderbender

    minderbender Initiate (185) Jan 18, 2009 New York

    Fun to imagine a Blichmann April fool's joke along the lines of a homebrew-scale fermenter that is as tall as a commercial cylindrical-conical but, you know, like a centimeter in diameter or whatever it takes to keep it within the 5-gallon range. "Brew like a pro! Ferment warm without an elevated ester level!" Could be made of stainless but with a sight tube.

    Not mocking the vase idea, by the way, which I think is interesting. I assume there is some kind of stopper that can fit in the vases?
     
    dmtaylor likes this.
  23. dmtaylor

    dmtaylor Initiate (199) Dec 30, 2003 Wisconsin

    I haven't figured out the top yet. For the time being I'm thinking foil or saran wrap.
     
  24. VikeMan

    VikeMan Meyvn (1,462) Jul 12, 2009 Pennsylvania

    Don't know about Wisconsin, but around here a foil covering would mean fruit flies in the wort/beer this time of year.
     
  25. dmtaylor

    dmtaylor Initiate (199) Dec 30, 2003 Wisconsin

    We get a few fruit flies just in July & August, not when it's cold like this in October. Great point, though. I'll have to figure out a more solid lid.