Brew pot

I am building my all grain rig and have a chance to pick up these 2 aluminum drums to turn 1 into a brew pot and the other into a mash tun. They are 22.5" in diameter and 24" tall. Just checking to see what the consensus is on using them.

No expert here, but it looks like you will have to supply an enormous amount of heat to the relatively small diameter bottom in order to overcome the heat lost from the very large surface area of the entire kettle.

bosco

Are they new, or was there something being stored in them?

How is 22.5" diameter small..? These are roughly 13 gallons each. I have an 8-gallon pot, and the bottom is about 18" across. Seems reasonable to me.

They are new, sealed on both ends and have been stored at my father in laws shop for I have no idea how long. He mentioned them when we were working on making my keggle.

They are 40 gallons each.

jschm19 said:

They are 40 gallons each.

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In your original post you stated "2 aluminum drums to turn into a brew pot."

If you intend on making a 48 inch high kettle with a 22.5 inch bottom I still think you are going to need a lot of heat..

Again this is just my opinion and as in many things over the years I could easily be wrong.

bosco

ps. It could also be dangerous.

Ah, yeah that's my error in explaining. I only want to use one as a brew pot and probably the other as a direct fired (somehow insulated) mash tun. I can't imagine what I would need to boil 70+ gallons of wort. Thanks Bosco, I will update my post to avoid further confusion.

jschm19 said:

Ah, yeah that's my error in explaining. I only want to use one as a brew pot and probably the other as a direct fired (somehow insulated) mash tun. I can't imagine what I would need to boil 70+ gallons of water. Thanks Bosco, I will update my post to avoid further confusion.

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Understood.

I was just worried about the possibility of the "percolator" effect that can occur when a tall column of water is heated at the bottom. Once the lower water reaches the temperature where it can boil it can expell the entire column above it. Like a geyser.

Good luck on the build.

bosco

I would be concerned of the wall thickness. IMO, anything under 3mm thick aluminum shouldn't be used, especially that large. If they're at least 4mm thick walls (bottom too), then you could do it. But, I would inspect the bottom welds (or whichever end will be the bottom) to make sure they're solid. The last thing you need/want is to have a weld fail at boiling temperatures, with one almost full of wort.

BTW, most aluminum pots are formed, not welded, so that there's no seam along the bottom edge (place for it to fail).

One might be ok for a mash tun, but I'd be very cautious about using one for a BK (without additional inspection).

They are welded up the side and then around the top and bottom. One end would obviously have to come off. I will mic them the next time I head over there. They are free to me if I want them, but I am trying to figure out if they will be worthwhile or If I should just convert a second keg and use my 10 gallon Rubbermaid mash tun until I find a third and can do a direct fired mash.

Without the actual spec's of the aluminum, it's hard to say. But, I would go onto the side of caution and not use them. IF you can get the actual alloy used in their construction, that could help. With them being as old as they appear to be (from your earlier post) I would doubt that information is available.

Without also knowing what they either held, or were made to hold, it's difficult to say to what spec the welds were made. They could have been fine for the intended duty, but will fail under use for brewing.

IMO, I would pass on them. Sell them for scrap if needed, and use those funds for more brewing gear.

Also, the melting/distortion point of the aluminum also worries me a bit. 18" of unsupported aluminum + 250 pounds of water + a whole lot of heat = failure? I could be over-thinking things so let me hear your thoughts.

jschm19 said:

Also, the melting/distortion point of the aluminum also worries me a bit. 18" of unsupported aluminum + 250 pounds of water + a whole lot of heat = failure? I could be over-thinking things so let me hear your thoughts.

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That's where alloy used as well as weld quality will seriously come into play. It's also why the material thickness is very important. I would even venture to say that 4mm thickness could be too thin for this application.

At 41 gallons capacity (each), that's a LOT of liquid. IF you fill one up, that's about 340 pounds of liquid in there. Leaving 2" head space leaves you with about 315 pounds of liquid alone (38 gallons).

How brave are you? Do you feel lucky?? Well, do ya??

Golddiggie said:

I would be concerned of the wall thickness. IMO, anything under 3mm thick aluminum shouldn't be used,

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3 mm!! That would be extreme! I just looked at my commercial pot that is 5 gallons and it is less than 1 mm. It is a single piece of metal with a rolled rim and riveted on handles.

They look sturdy enough to me but when you cut off one end you will have to determine if they are stable enough.

For the BK I would test it with just a couple of gallons to make sure the bottom is able to take the heat and weight then again with more water then even again mostly full before making any major modifications like installing valves etc.

jschm19 said:

Also, the melting/distortion point of the aluminum also worries me a bit. 18" of unsupported aluminum + 250 pounds of water + a whole lot of heat = failure? I could be over-thinking things so let me hear your thoughts.

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13 gallons of water would weigh somewhere around 104 pounds!

Edit: Oops - looked at a reply that stated 13 gallons these actually calculate out at about 41.3 gallons. I have to agree with the cautions listed. What alloy of aluminum, has anything been in them?, are they strong enough especially filled with hot wet grain?

Added: They might also be difficult to use if you are not going to be doing 20+ gallon batches!

kh54s10 said:

3 mm!! That would be extreme! I just looked at my commercial pot that is 5 gallons and it is less than 1 mm. It is a single piece of metal with a rolled rim and riveted on handles.

They look sturdy enough to me but when you cut off one end you will have to determine if they are stable enough.

For the BK I would test it with just a couple of gallons to make sure the bottom is able to take the heat and weight then again with more water then even again mostly full before making any major modifications like installing valves etc.

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I bought an aluminum pot from a restaurant supplier before, that was 4mm thick so that it would stand up to the use level. IMO, the small ones you get, in the 1mm thickness, are designed for very lite, very infrequent use. With the amount of heat we use them with, for the amount of time, I wouldn't want just 1mm of material there. Plus, there's a thread on these boards about thin thickness aluminum pots having serious distortion on the bottoms.

I would also do a test with the maximum amount of liquid, for [at least] the maximum boil time you'll put it under. Do it again a day, or week, later and check for any distortions. If it's distorting even a tiny amount, S-can it.

Seriously here, as much as I like making things for brewing out of something that was never built for it, this is a dangerous space. Having many gallons of boiling hot wort in something that's not 100% up to the task is putting you into serious harms way. Unless you don't mind getting 3rd degree burns over large sections of your body from it failing (due to not testing it).

BTW, during the test, don't be near it. Be far enough away so that if it does fail, you won't be hit by a tsunami of boiling hot water.

Well, as much as I would love to have them I think the quantity of massive batches I would brew along with the fear of failure, most likely catastrophic, is leading me to think I should pass on these. I'll probably check the thickness and see if I can find out anything else out about them, but for now I will stick to sub 15 gallon batches.