FAQ: Aluminum Pots for Boil Kettles?

[Indian_villager]

Well. I just bought a 40qt aluminum pot and am putting a 1500w element to supplement my stove. And a drain valve. It is my own fault for not looking up the galvanic corrosion issue. But reading above puts me at a bit of ease.

 

[MrIPA]

I havent been able to find any definitive information on this in off the SS vs Al pot discussions. But do you think there is any noticable difference in propane usage given the fact that the thermal conductivity of Al is so much better than SS. For reference the conduction coefficient of Al is 250W/mK where SS is only 16W/mK

Found this on the internet though

Example - Conductive Heat Transfer through a Aluminum versus Stainless Steel Pot
The conductive heat transfer through a pot wall can be calculated as

q / A = k dT / s

where

q / A = heat transfer per unit area (W/m2)

k = thermal conductivity (W/mK)

dT = temperature difference (C)

s = wall thickness (m)

Conductive Heat Transfer through Aluminum Pot Wall with thickness 2 mm and temperature difference 200C
q / A = 250 (W/mK) x 200 (C) / 2x10^-3 (m)

= 25000 (kW/m2)

Conductive Heat Transfer through Stainless Steel Pot Wall with thickness 2 mm and temperature difference 200C
q / A = 16 (W/mK) 200 (C) / 2 10-3 (m) = 1600 (kW/m2)

 

[SpikeBrewing]

Well most Al kettles are 4-6mm thick and most SS kettles are .8-1.2mm thick so here's the updated #'s:

Conductive Heat Transfer through Aluminum Pot Wall with thickness 5 mm and temperature difference 200C
q / A = 250 (W/mK) x 200 (K) / 5x10^-3 (m)

= 10000 (kW/m2)

Conductive Heat Transfer through Stainless Steel Pot Wall with thickness 1 mm and temperature difference 200C

q / A = 16 (W/mK) 200 (K) / 1x10^-3 (m)

= 3200 (kW/m2)

So the aluminum will conduct heat in at a rate 3 times more than the stainless BUT it will also conduct heat out 3 times quicker too. Since there is more wall area than bottom area the heat lost may equal out the Al and SS or Al may end up losing more heat due to the large wall surface area and higher conductivity.

 

[xtian116]

I'm cheap, so I use aluminum pots that I get for tamales. A 52qt pot for $30, you can't go wrong. I did notice, when I was oxidizing them, they actually retained the heat pretty well. It was in the high 40s over night outside, they were still over 120 degrees the next morning. (After about 7 hours)

 

[Hall_Brewing]

passive oxide layer must be built up before brewing (**see note below) with a new aluminum kettle, although it is very easy to maintain

Where is the note that says how to do this?

 

[xtian116]

passive oxide layer must be built up before brewing (**see note below) with a new aluminum kettle, although it is very easy to maintain

Where is the note that says how to do this?

Just fill it up and boil water in it for at least an hour before you use it. Personally, I did 2 hours but kept topping it off as water evaporated.

 

[CGVT]

Just fill it up and boil water in it for at least an hour before you use it. Personally, I did 2 hours but kept topping it off as water evaporated.

Overkill, IMO.

Just take it out of the box and use it. It will be fine.

 

[wilserbrewer]

Overkill, IMO.

Just take it out of the box and use it. It will be fine.

Yea I'm tempted to agree here as well...perhaps a little cleaning prior to use is warranted, but I agree that the level of concern for oxidizing aluminum pots is overstated...aluminum will oxidize plenty through use.

I've never read a post, "first batch ruined, didn't oxidize my kettle". Aluminum oxidizes to some extent in air almost instantly.

 

[xtian116]

Yea I'm tempted to agree here as well...perhaps a little cleaning prior to use is warranted, but I agree that the level of concern for oxidizing aluminum pots is overstated...aluminum will oxidize plenty through use.

I've never read a post, "first batch ruined, didn't oxidize my kettle". Aluminum oxidizes to some extent in air almost instantly.

Your both probably right. When I first started I don't even think I cleaned that turkey fryer when I un-boxed it. Figured is was going to be boiled. When I got my bigger pots, I was a little overkill on them because I wanted them to look like the old ones. Maybe it was my brewing that got better and not the layer on the pot.

 

[CraigHathcock]

Just ruined an aluminum kettle with oxy clean...... lesson learned read first! Correction read everything first....

 

[wilserbrewer]

Just ruined an aluminum kettle with oxy clean...... lesson learned read first! Correction read everything first....

Unless there are holes in it, I can't see it being "ruined". If it is just very ozidized and black inside, that is not ruined IMHO.

 

[petey_c]

It's probably not ruined. The oxiclean removed the oxide layer. Re-boil and you should be good to go.

 

[TheRooster]

Great FAQ, flyguy!

 

[jaemus]

Sounds like FlyGuy was simply trying to do a good thing...
Also sounds like abracadabra was having to be the fly in the ointment, no pun intended
Thanks FlyGuy for doing what I set out to find, having a question answered

 

[Meat6895]

I'm sure it's fine. But even with caked on and burnt sugar I can take the top rack out of my dishwasher and it fits in there. I had a boil over my first solo boil and it was a mess but it still looked new out of my dishwasher.

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[NewBrewer_B]

Anybody read the "Toxicology of Metals" by Luis W. Chang Ph D? There is an entire chapter (23) on Alzheimer's Disease by D.R. McLachlan, P.E. Fraser, E. Jaikaran, and W.J. Lukiw. A good read. People can say Aluminum is fine all they want, but I'm not taking the chance. I thought it was an interesting sentence in the book "The long-accepted commercial use of aluminum and its compounds has led to considerable resistance to investigating the possible role of aluminum in human disease." The conclusion on Page 395 also states that there is "robust evidence" that aluminum is involved in AD.

 

[p40whk]

Question, I had a house fire and my aluminum pots were very close to the fire, they are not deformed yet they are a bit scorched. Since Aluminum is porous, it would have absorbed a ton of soot and I'm wondering if this will impart off flavors to my beer?

Insurance is paying to replace what got ruined so before I decide to trash these pots I'd like to know if they're no good for brewing.

 

[petey_c]

Insurance is paying to replace what got ruined so before I decide to trash these pots I'd like to know if they're no good for brewing.

Warhawk, will they pay to replace the pots? If they are, they usually let you keep the old ones. You could then brew a test batch and educate the rest of us.... Just sayin.

 

[p40whk]

I'm probably going to replace them as I really don't want to have those flavors in my beer. Not to mention that they got pretty hot by the fire then doused with that chemical foam the fire department used to put it out. Not sure if it's safe to use or not but I could boil something in it to find out.

 

[augiedoggy]

Anybody read the "Toxicology of Metals" by Luis W. Chang Ph D? There is an entire chapter (23) on Alzheimer's Disease by D.R. McLachlan, P.E. Fraser, E. Jaikaran, and W.J. Lukiw. A good read. People can say Aluminum is fine all they want, but I'm not taking the chance. I thought it was an interesting sentence in the book "The long-accepted commercial use of aluminum and its compounds has led to considerable resistance to investigating the possible role of aluminum in human disease." The conclusion on Page 395 also states that there is "robust evidence" that aluminum is involved in AD.

yup its been mentioned here many times...
Its just like the old cellular phones and the "silver" tooth filling they used (and still use) that are actually made of heavy metals including mercury.... this stuff will SLOWLY be phased out as to not cause panic and billions in lawsuits.

And While they are certainly not the best choice (may I remind you that Drinking alcohol isnt exactly the healthiest thing for your body either) in most cases it wont cause any serious harm...(depending on who you talk to and how much exposure is involved).
the sad fact is until someone provides inconclusive proof and shows this to the RIGHT people nothing will be done either way. and maybe the threat just isnt that real?

 

[dkevinb]

yup its been mentioned here many times...
Its just like the old cellular phones and the "silver" tooth filling they used (and still use) that are actually made of heavy metals including mercury.... this stuff will SLOWLY be phased out as to not cause panic and billions in lawsuits.

And While they are certainly not the best choice (may I remind you that Drinking alcohol isnt exactly the healthiest thing for your body either) in most cases it wont cause any serious harm...(depending on who you talk to and how much exposure is involved).
the sad fact is until someone provides inconclusive proof and shows this to the RIGHT people nothing will be done either way. and maybe the threat just isnt that real?

The difficulty with studying the effects of aluminum exposure is that it is EVERYWHERE in the environment. It is the 3rd most abundant element on Earth. It's in spinach, tea, and drinking water. Should you stop eating spinach, drinking tea, and drinking water?

Alzheimer's has also been blamed on flu shots and silver dental fillings. Those have also been disproven. The only solid ties to Alzheimers found so far are genetics, metabolic and vascular disease, and the lack of intellectual stimulation. Like almost all diseases the best prevention is to eat right, exercise more, and pick good grandparents.

 

[Gmull70]

Yea I'm tempted to agree here as well...perhaps a little cleaning prior to use is warranted, but I agree that the level of concern for oxidizing aluminum pots is overstated...aluminum will oxidize plenty through use.

I've never read a post, "first batch ruined, didn't oxidize my kettle". Aluminum oxidizes to some extent in air almost instantly.

So true I bought an aluminum pot 4 years ago and make beer that tastes pretty good

 

[Bobcatbrewing42]

I bought a 20 year old 10 gal aluminum pot from a home brewer. It has well oxidized coating and is thick enough to use as a car jackstand. I boil and mash in keggles but it is a great hot liquor tank and backup boil kettle. Hard to beat for $20.

 

[rowan57]

I don't reckon there are a lot of commercial kitchens using SS, certainly the Michelin star kitchen I worked in when younger was all aluminium pots. My aluminium pots are probably 4mm thick and solid as a rock, I wouldn't switch 'em for cheap SS any day.


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[tvic31]

This is great stuff. One question, do you have to continue to build the passive oxide layer on AL pots before each brew or is once enough?

 

[zefbrew]

This is great stuff. One question, do you have to continue to build the passive oxide layer on AL pots before each brew or is once enough?

Once is enough, and then each time you brew normally, the oxide layer will maintain itself

 

[msa8967]

Is there any other way to build up the oxide layer other than boiling water or placing it in the oven? I read somewhere that filling it with water and letting it stand overnight would build up the oxide layer or even adding some oxyclean to the water would build it up. This seems too simple so I am curious to know if it is true.

 

[zefbrew]

Is there any other way to build up the oxide layer other than boiling water or placing it in the oven? I read somewhere that filling it with water and letting it stand overnight would build up the oxide layer or even adding some oxyclean to the water would build it up. This seems too simple so I am curious to know if it is true.

I'm sure leaving it overnight will start the layer, but boiling the water for a few minutes(maybe 20 minutes at least) and then dumping the water out while it is still hot makes a real nice layer. If you are worried about wasting the energy of boiling water, use the water you boiled for dishes or washing clothes or the bath, at least then no energy was wasted

 

[CGVT]

I took mine right from the box and used it to brew beer. I wasn't worried about conditioning the pot. I doubt that restaurants condition their aluminum pots before using them. My beer was fine and I haven't grown a third arm out of my forehead yet.

 

[msa8967]

I'm sure leaving it overnight will start the layer, but boiling the water for a few minutes(maybe 20 minutes at least) and then dumping the water out while it is still hot makes a real nice layer. If you are worried about wasting the energy of boiling water, use the water you boiled for dishes or washing clothes or the bath, at least then no energy was wasted

I should have been more clear in my original post. I was questioning the science (is it true) about just using water over night to condition the pot. I will boil mine and use the water for chilling later in a cold ice bath.