Most winemaker's arsenals have or have available to them carboys from sizes 7.5 gallons all the way down to tiny tincture bottles, however one size that seems to be missing from the list is 5.5 gallons.

We have 7.5, 7, 6.5, 6 then it goes to 5

For people who target 5 gallon batches and step down in sizing rather than adding water to back-fill, 5.5 gallons seems to be a missing step from the progression. Why hasn't this gap been filled?

  • You are correct. It is inexplicable however there are some "non standard" ones in that size range kegco.com/home-brewing-equipment/carboys/sd-6076j
    – K4 Nerd
    Commented Oct 7, 2019 at 21:52
  • So there is that, I have some of their 7 gallon wide mouths because wel I just don’t like buckets and that’s what I use the 7 gals for, but for a carboy for long term fermenting or aging, I really prefer having a smaller mouth and reduce the amount of surface area on top. I don’t see kegco products as really best for bulk aging and similar.
    – Escoce
    Commented Oct 7, 2019 at 21:55
  • For brewing this is a non issue and most of these are geared towards brewers. For winemaking, most people quickly outgrow 5 gallon batches if they get serious. I think I made one five gallon batch before I made 55 gallons to put in a barrel. The minimum size I would ever make for wine would be about 15 gallons and there are demijons and kegs for that. Commented Oct 10, 2019 at 22:11

1 Answer 1


There must be some historical reason for that, which I don't know.

However, there are some 5.5 gallon available now:

  • I have to be honest. I have two of the 7 gallon kegcos. I don’t consider them carboys, I consider them glass primary or short term secondary fermenters. A carboy has a narrow opening. These have 6 inch openings. They are valuable tools, but for long term secondary/aging/storage, I don’t think they fit the bill that a carboy does. At best, you can only reduce the surface area of your wine to 6 inch diameter. That’s too much for my comfort. Especially in the case of occasionally pulling the bung to thief out some wine, it’s just a much larger infection vector.
    – Escoce
    Commented Oct 10, 2019 at 15:30

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