Aluminum vs Stainless? Best Beer Brewing Pots

by Brad Smith on August 17, 2010 · 26 comments

A perpetual debate among home brewers and on various discussion forums is the merits of aluminum vs stainless steel pots for brewing beer. This week we look at the pros and cons of each to help you make your own educated decision on your next beer brewing pot.

Aluminum Pot Pros and Cons

Aluminum pots are widely available and inexpensive because aluminum cookware is widely used for preparing foods. Inexpensive Turkey pots in the 36 quart range can be found at your local Walmart, particularly right after Thanksgiving at great prices. Aluminum pots cost considerably less than stainless steel – often half as much. Aluminum is a better conductor of heat than steel, so your pot will come to a boil faster and also cool down faster after you are done boiling.

The only major disadvantage of aluminum is that it will oxidize, so you can’t use oxygen-based or caustic cleaners such as Oxyclean. This is the major reason why professional brewing equipment is made of stainless steel and not aluminum – the stainless steel is easier to clean with caustic cleaning agents. Also, over time aluminum will get an oxide layer over it which can discolor the aluminum and give it a grey tone. This is not a cause for concern – the layer of aluminum oxide actually protects the pot, but it is not as pretty as stainless steel.

I feel it is important to address a number of myths about aluminum. First, aluminum pots are not linked to Alzheimer’s disease. A number of medical studies since the 1970′s have found zero link between Alzheimer’s and the use of aluminum. Keep in mind that every day you drink soda from aluminum cans (though most are lined) and eat food prepared in aluminum cookware – it is safe.

A second myth is that aluminum will react with acidic content of the wort and either add off flavors or eat away at your pot. This is also untrue – water has a pH of7.0, your wort has a pH of around 5.2, while spaghetti sauce can run as low as 4.6 and the most acidic diet sodas you drink run as low as 2.5. For comparison, battery acid has a pH of 1.0. Your wort is simply not acidic enough to react with your aluminum pot.

Stainless Steel

Stainless steel pots are the “Cadillac” of brewing pots, with designer pots running into the many hundreds of dollars in price. They are more expensive than comparable aluminum pots, but are a favorite of serious brewers. Stainless steel will remain shiny, as the passive oxide layer is not visible – so its easy to tell when your stainless pot is truly clean.

An advantage of stainless steel is that you can use oxygenated cleaners on it, which makes it a favorite with professional brewers who need to clean large vats. You should avoid long term exposure to bleach based cleaners as these can pit your stainless steel pots and vessels.

Stainless steel is stronger than the softer aluminum metal, so it is less prone to denting and scratching for a comparable wall thickness. However, you are unlikely to outlive a well made stainless or aluminum pot in either case. Stainless has a strongly bonded oxide layer, so it is less susceptible to attack by acids, though again the acidity of wort is not a concern for either metal.

The major disadvantage of stainless steel is that it does not conduct heat as well as aluminum, which means a longer time to reach boil and also longer cooling times after the boil.

Which to Choose?

If you select a well made heavy-duty pot, large enough for a full boils that is heavy and conducts heat well, you can’t go wrong with either stainless or aluminum. I look for a heavy pot with thick walls as it will conduct heat better and also hold up well to the occasional nicks and dings. An ideal pot has a diameter approximately equal to its height. A well made aluminum or stainless steel pot will likely last a lifetime.

If you are a brewer on a budget, you can’t ignore the large price advantage of aluminum – often it costs half as much for a comparable pot. Stainless steel has a “cool factor”, but it also has a price associated with being cool. Now I personally use stainless steel, but I’ve also been brewing for 25 years and started out using a cheap kitchen pot.

Do you have your own thoughts? Leave us a comment below. If you want to support us, you might want to consider a pot from Adventures in Homebrewing, a BeerSmith Supporter here. Thank you for reading this week’s BeerSmith Home Brewing Blog, and don’t hesitate to subscribe if you want more great brewing articles on a regular basis.

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{ 24 comments… read them below or add one }

stevo155 August 18, 2010 at 4:35 am

Get the best of both worlds. I have a 10 gallon SS pot that has a layer of aluminum sandwiched between SS on the bottom of the kettle.

Jeff August 18, 2010 at 5:00 am

I just ordered my second 15 gal aluminum pot. The walls are 3/16 thick, and all for $50 shipped. Can’t come close to that price with stainless. This is a hobby for me, so I have to stay within my hobby budget, so for me the choice for aluminum was a no brainer, and it works great.

Now I just need to think about adding ball valve to both so I can start doing some 10 gal batches.

JC August 18, 2010 at 8:41 am

Brad-

One minor point about aluminum cans is that they are internally lined, so no aluminum actually comes in contact with the beverage unless the liner gets damaged.

That being said, I use aluminum for my brew pot for the reasons you stated. A 32qt aluminum “tamale pot” was $18 at target… beat that! Boiling plain water in it one time put a good, strong oxide layer on it that will protect the pot.

Brad Smith August 18, 2010 at 10:50 am

Thanks – I made a correction to the article to note that the soda cans are lined. — Brad

ClockworkSoul August 21, 2010 at 5:55 pm

Hi, Brad.

Another minor point… battery acid is around 30% sulfuric acid by mass (around 5M for us chemistry geeks), which has a pH around -1, making it about 3100 times more acidic than a 2.5 pH soft drink. You’re dead on about aluminum and acids though: aluminum surfaces form an oxide coating when exposed to air that makes it pretty much impervious to any acid you’re ever going to have around your kitchen! (You don’t keep undiluted hydrochloric acid around the house, right?)

Certain chemicals aren’t good around aluminum though because they can both remove this oxide coating and dissolve the aluminum underneath. The three biggies are: sodium hypochlorite (household bleach, but it’s very dilute), sodium percarbonate (most oxygen based cleaners), and especially sodium hydroxide (which is in lots of the caustic industrial cleaners you mentioned).

Brad Smith August 22, 2010 at 9:02 am

Thank you for the tips on the chemicals!

Best Beer September 17, 2010 at 6:12 am

Thanks for the tips on using pots when brewing beers. This thing really helps.

Greg January 3, 2011 at 3:50 pm

So I just bought a fryer and used the 32q aluminum pot to make a batch of beer without doing the boil in to get the oxide layer on the pot, wort tasted fine when i sampled it, and all seemed alright… not doing the boil in i guess you call it, will that damage these pots? I plan on doing it before my next batch of beer, but i already do one.. hopefully i didn’t destroy this batch of beer, it’s fermenting now i guess i’ll find out in a few weeks when it goes to the keg….

Brad Smith January 4, 2011 at 6:37 am

Greg,
Its unlikely you did any damage – a fine layer of oxide forms over the aluminum even as it is sitting on the store shelf. It just becomes more visible and obvious with use. I would just enjoy the beer!

Brad

Aluminum Plate February 16, 2011 at 1:39 pm

Interesting article. Home brewing brings back fond memories. My best friend’s brother used to do it in the ’80s… with mixed results.

Thomas January 4, 2012 at 3:42 am

Hi Brad,

I’m a professor of biology and my research is Alzheimer’s disease (AD). I would have to disagree with you on stating that Al is definitely not involved and completely safe. One of the problems we see in AD is neurofibrillary tangles. There is strong evidence that Al is playing a role in these tangles, at least some of the time. Further, it is unclear what else Al is doing. Like lead (Pb) Al is toxic to the young much more so than the old. So I’d probably recommend a pregnant woman try and avoid Al and also recommend parents avoid giving anything containing Al to young children or babies, just to be safe. But again, the precise nature of Al is still not clear. Mostly because no one was investigating it until recently. 5 years ago if someone had asked me about Al and AD or cancer I would have said I have no idea. But today there are a multitude of studies. According to one review article around 68% of peer reviewed studies they analyzed found a link between AD and Al. Therefore, I wouldn’t freak out from eating Al but I, personally, try to avoid it. Also, it is not an essential mineral. It doesn’t appear that our bodies need it or want it so why take the risk?

Lastly, this post only addresses the concern over AD and not cancer. As I’m not a cancer researcher I’m not going to try and say one thing or another on the subject. But it is worth noting that there may be a link between Al and cancer. (Just for clarification, I am not talking about breast cancer here.)

Sincerely,
Thomas

Brad Smith January 10, 2012 at 10:47 pm

Thanks Thomas – that is counter to the information I have found, especially given the huge number of aluminum cooking pots on the market but thanks for the info!

Mike February 4, 2012 at 11:19 am

Thomas, I have also read similar information before; however, this is a beer forum. 5 year olds and pregnant women are not drinking and probably not brewing beer, but if they are then that is a whole other discussion! lol.

Jen April 12, 2012 at 1:24 pm

I have a 40 quart Wearever Aluminum pot that I bought at a garage sale for $1 and have been brewing in for 13 years. talk about an awesome return on investment :)

Brian D May 20, 2012 at 12:53 pm

Will PBW hurt an aluminum pot? I’ve read the label and it only says not to use it on Teflon. I’m thinking of getting an aluminum boil kettle but use PBW for clean up and love it. Thanks.

Landon August 8, 2012 at 2:21 pm

Brian D,
PBW will definitely harm you’re aluminum pot, do not use! My idiotic self tried this one time and I may have left it in there for 20 or 30 minutes, when I came back I found that the inside of my pot looked like the moon with numerous craters and it pretty much ruined it. The next several hours were spent sanding them out, brushing and then boiling over and over to make sure all the aluminum excess was removed. Needless to say not a high point in my brewing career!

Dave Hennessey September 3, 2012 at 12:29 pm

Brad, Besides the “cool” factor, 304 Stainless Steel is the standard for the food preparation industry. Look in the kitchen of your favorite restaurant – everything is SS, including countertops and walls. It’s easy to clean, impervious to most chemicals, quickly regrows its protective oxide layer when scratched, and will take a beating. Knives and forks and spoons are all stainless steel. Commercial beer kegs and homebrew Cornelius kegs are 304 stainless. Type 316 (more corrosion resistant) is used in the pharmaceutical industry, which is just really advanced cooking.

In the home kitchen, pots and pans are typically aluminum simply because of cost. But when you really burn something, you throw out the pot and buy a new one.

I think the real criterion is your intended purpose. If you’re doing extract brewing on the kitchen stove, a good aluminum pot is inexpensive and will do exactly what you want it to. When/if you advance to all-grain brewing or serious production, you’re probably going to want to add some fittings and valves – impractical with aluminum. That’s when it’s time to shell out the big bucks for something like a Blichmann Boilermaker.

Joe November 27, 2012 at 10:45 pm

Hello, I’m wanting to try open fermentation and it would be very expensive to do it with stainless. Would an aluminum pot work?

Thank you,

Christopher Jackson August 31, 2013 at 11:00 am

@dave…why are fittings and valves impractical with aluminum pots? I find them to be more practical from the standpoint of installation.

brewJack September 2, 2013 at 1:32 am

IMO, stainless is a superior material. I wouldn’t ferment in an aluminum vessel as the both surface area in contact with the metal, time that the liquid is exposed and the pH of the liquid will affect the amount of “aluminum like flavor”. The things that makes stainless a superior material is its resistance to corrosion, easy of welding, lower heat transfer rate.

The reason that heat transfer rate is important is that if you heat a batch of beer on an iron element in a thin aluminum pot you will be able to see exactly where the element was touching pot as there will be a large amount of malt burned to the bottom. This will increase the amount of non-fermentable sugars in the beer (especially if you scrape the bottom ;) thus more sweetness less alcohol. This can become a problem in high gravity batches.

As mentioned aluminum forms an oxide layer which is eroded during long periods of contact with low pH liquids. Similarly, I have boiled my copper chiller in a 1:20 vinegar to water solution for 1 hour and the copper comes out of the bath looking shiny and new. The oxides in aluminum can and will contribute to off flavors which will become noticeable over longer periods of time. This can be a problem if the beer is intended to be laid down for a longer period of time.

Finally, both metals have their drawbacks when it comes to welding or cutting but stainless is by far the more forgiving of the two. Since its hardness is higher it will scratch less and not as deep which means less microbes hiding in hard to reach places. This is important if you are using a ice bath to reduce your wort to fermenting temperatures.

My pot is 16.25 Gal., 304 stainless, NSF certified which I modified to fit a weld less ball valve and thermometer. My total cost is was 300 dollars even 6 years. The bottom of the pot is a 12 ply sandwich of copper and stainless which increases the heat transfer rate while keeping the distribution of heat even. I still have hot spots on the bottom but this problem is minimal. My total cost is was 300 dollars even 6 years ago. It is an investment and is worth it. For beers with high residual sweetness I have to boil for at least 1.5 hours. Try doing that with a cheap aluminum pot. Stainless isn’t a “Cadillac” it is a commercial grade product which is built to last.

My advice is to hold out for the better option. You may save money on aluminum and maybe you can make it work. But, if you wanted to make cheap beer why not just buy an ice beer? Brewing is minimizing the things that will make your beer bad, the brew kettle can ensure that your hot/cold break, hop extraction and sugar development happen how they are supposed to.

Cheers.

Superchop728 September 7, 2013 at 6:45 am

Just bought a 10 gal brew kettle to try BIAB. My other kettles are stainless steel. I usually use PBW or oxyclean. The posts above say not to use either. So what is recommended? Thank you

Old Dog November 19, 2013 at 8:32 pm

The PBW Tech Sheet says it is safe to use on aluminum:

http://www.midwestsupplies.com/media/downloads/311/PBW%20Tech%20Sheet.pdf

FavoriteDaughter December 1, 2013 at 11:27 pm

I’m looking to purchase a stainless pot for my dad for Christmas. He mentioned something about avoiding a brushed interior so the wort will not stick. Is this a rational concern? Do you have any recommendations on these type of things? I’ve been looking at various home brewing supply sites, and I am getting frustrated because I cannot tell if the items I’m viewing have a brushed interior.

dirty bird brew May 11, 2014 at 9:41 am

great article you just saved me a easy 100$ and a large butt chewing.

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