20 gal Carboy?

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Well-Known Member
Feb 17, 2009
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Silver Spring, MD
I have a line on a couple free carboys from work. The person with them estimated that they're about 2.5 feet tall, maybe 20 gals. I will be checking them out during lunch and had a couple questions.

a) I currently only use buckets, but 2.5 feet sounds about the right height for a 6.5 gal carboy, right? I feel like a 20 gal carboy that high would have to be really really fat.

b) If it is 20 gals, would the headspace be a major problem? Would it be better suited for primary or secondary?

Background, I do 5 gallon partial boil extracts.
I'll give you the exact measurements of a 6.5gal carboy.

They are 21" tall to the lip, and they are 12.5" wide (diameter). They will hold about 7.5 gallons of liquid if they are completely full, but they will ferment 6.5gal batches WITH headspace for the Krausen.

The likelihood these are 20 gallons is so far from a real possibility... they would have to huge.
If they are 2 1/2 feet tall, that is approx 1.5 times the height of a 6.5 gallon carboy (21"). Keeping the proportions constant, 1.5 times bigger in all 3 dimensions is 1.5x1.5x1.5=3.375 times the volume of the 6.5gallon carboy or about 22gallons!
Also - the term "carboy" doesn't just refer to round containers. Carboys come in all sorts of shapes and materials. Just look at any lab supply website.
If it is 20 gallons, you better have it where you want to leave it before you fill it. 20 gallons of water weighs 160 pounds. I wouldn't want to lift that sucker up onto the counter to rack out of it.
Volume = pi x r^2 x h

20 gallons = 4620 cubic inches [from here]

So, if it is 30 inches tall, it would need a radius of 7 inches (14 in diameter) to hold 20 gallons (assuming a geometric cylinder).

If you currently do 5 gallon partial boils, you are going to need a bigger pot :D
Could he have made a mistake and read the 20 as gallons, when really it's liters? 20 liters = ~5.3 gallons.
Well, I'm the proud owner of three 5 gallon carboys. They're currently strapped into my backseat, along with a bonus 1/2 gal carboy. They're not standard LHBS carboy and the guy I picked them up from didn't know what they were originally used for, just that they haven't been used in years. So after a very hefty cleaning, I will have 3 new secondary containers! Score!

Thanks for the input, I have no idea why they thought it might be 20 gals. The side even has "5 gal" imprinted on each of them quite largely.
Pics, please! Are they glass? You'd better devise some way of carrying them, lest they shatter on you. You don't want to risk a trip to the ER, or worse, spilled beer.:eek:
I'll try to get pics of the haul up sometime tonight, I got a poker game and a starter to make tonight. One the them has a glass spigot on it which I'm a little leary of. If you've never seen something like that, the entire spigot is made of glass, and the valve is glass thats been lubed with a silicone gel so it turns. My worry is that if it's closed, the beer will still be in contact with the silicone gel, which probably isn't great. So that one won't be used until I can figure out a way of sealing off the inside of that spigot. And I have to get a stopper for one.
They sound like cast-offs from a laboratory of some sort. I think you might want to be VERY careful with that carboy that has the glass spigot...even if you could sanitize it, one misstep could break that spigot off and you'd have a stream of beer all over your house.

In a laboratory setting those puppies using sit on a shelf out of the way and do not get moved often for that reason. At least they used to...not sure how many laboratories still need to make 5 gallons of a solution these days...
As long as you cleaned it and used a food grade silicone gel (just like keg lube..) I think a racking port on a 5 gal glass carboy would be pretty sweet :)

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