Homebrewing beer and galvanic corrosion

In summary: assuming you're not putting something directly on the parts of the pot that come into contact with the water.
  • #1
coktail
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1
I’ve started home brewing beer recently, and I’m assembling equipment for my first 5 gallon batch. The technique I’ll be using requires me to put grains into a nylon bag and then steep that bag of grains in hot water (approx 160°), much like a giant teabag. The trick is that the bag cannot touch the bottom of the stainless steel pot I’m using or I risk scorching the nylon bag. The typical way to avoid this is to put something between the bottom of the pot and the bottom of the bag. Often people will use a perforated pizza pan, such as this: http://www.foodservicewarehouse.com/browne-halco/57-5354/p7325.aspx

People will then put nuts and bolts through some of the holes in the pan to act as legs, which raises the pan slightly from the bottom of the kettle. The bag can then rest safely on the pan without risk of touching the bottom of the kettle and scorching.

However, this pan is aluminum, and my kettle is stainless steel, as are the recommended bits of hardware with which to make the legs. I’ve been doing some reading about galvanic corrosion, but I haven’t been able to get a clear answer from the homebrew forums about wether or not this would be a problem for me. It seems like the metal could corrode over a long amount of time, but even if I take care to minimize this, I’m still worried about impurities getting into my beer. I’d really just like to avoid any sort of nasty chemical reaction at all if possible.

I cannot for the life of me find a stainless steel perforated pizza pan. Of course they’re available unperforated (just my luck), but I don’t really feel like drilling hundreds of little holes into a non-perforated pan such as this: https://www.amazon.com/dp/B000SSVP5S/?tag=pfamazon01-20

There is another option I’ve discovered which I’ve never seen mentioned on the homebrew forums, and that’s to use a steel-plated grill grate, such as this: https://www.amazon.com/gp/product/B000WEIKL0/?tag=pfamazon01-20

I’m not sure if steel-plated is good enough, or if it needs to be solid steel. I’m assuming that the steel used here is stainless, but I don’t know for sure.

Lastly, some people will use a steam rack such as this: https://www.amazon.com/dp/B007WAC8H4/?tag=pfamazon01-20

These are chrome-plated, and I don’t know if that’s any better or worse than aluminum or steel-plated.

Any and all advice is greatly appreciated. Thank you!
 
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  • #2
I'm going to assume you are using the brew in a bag technique and not just steeping specialty grains for an extract brew. If that's the case, I would get the water to 160 degrees without the bag or grains in the kettle and turn the flame off. Then add the bag and grains, stirring well and let it sit. If you need to raise the temperature (and you most likely will for an hour long mash in an un-insulated kettle) turn the flame on very low and stir. Stirring is key. If you wanted to add something to the bottom of the kettle to protect the nylon bag, maybe a stainless steel false bottom like this (this might be too big, not sure what size kettle you are using): http://www.northernbrewer.com/shop/abt-large-hole-false-bottom-1-2-hole-no-elbow.html or what about using a SS vegetable steamer basket that doesn't have the middle post like this: https://www.amazon.com/dp/B000LNP4C0/?tag=pfamazon01-20
 
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  • #3
You assume correctly! I am doing BIAB.

I have heard that stirring help to avoid scorching the bag, or that you can simply lift the bag while the heat is on. Or I could simply wrap my kettle in a blanket to keep the heat in during the steeping process.

Still, I’m interested in having something in the bottom of the pot just in case. Better safe than sorry, I say. The steamer you linked to is another good option, but I haven’t been able to fine one of the proper size. The other product you linked to looks good, but it’s $50, which is more than I’m hoping to spend.

Ultimately my question is about galvanic corrosion and whether it will occur with a stainless steel pot and an aluminum object inside of it. OR, if corrosion will occur between stainless steel and an object coated with a steel alloy, such as this: https://www.amazon.com/gp/product/B000WEIKL0/?tag=pfamazon01-20

Thanks for your response!
 
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  • #4
Galvanic corrosion requires both metals to be in electrical contact, so any insulator that will separate metals and survive the temperature (glass, plastic) will guarantee you are on the safe side.
 
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  • #5


I would like to offer some insights and recommendations regarding the use of different materials for the purpose of avoiding galvanic corrosion in homebrewing. First of all, it is important to understand the concept of galvanic corrosion and its potential effects on the quality of your beer.

Galvanic corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte (such as water). In this case, the stainless steel pot and the aluminum or steel-plated pizza pan or grill grate would be in contact with each other, and the hot water used for steeping the grains would act as the electrolyte. This can lead to the transfer of ions between the metals, resulting in corrosion of the less noble metal (aluminum or steel) and potentially causing impurities to leach into your beer.

Based on this understanding, using a solid stainless steel perforated pizza pan or a stainless steel steam rack would be the best option to minimize the risk of galvanic corrosion. Stainless steel is a more noble metal and is less likely to corrode when in contact with other metals. Additionally, using a solid stainless steel option eliminates the potential for impurities to leach into your beer.

Using a steel-plated grill grate or a chrome-plated steam rack may also work, as long as the plating is intact and not scratched or damaged. However, there is still a risk of galvanic corrosion and potential impurities from the plating.

In conclusion, it is recommended to use a solid stainless steel option for the purpose of avoiding galvanic corrosion and ensuring the purity of your homebrewed beer. While it may be more difficult to find or require some DIY work, the end result will be worth it in terms of the quality and safety of your beer. Happy brewing!
 

1. What is galvanic corrosion?

Galvanic corrosion is a type of corrosion that occurs when two different metals are in contact with each other in an electrolyte solution (such as beer) and a current flows between them. This leads to the deterioration of the more reactive metal, while the less reactive metal remains intact.

2. How does galvanic corrosion affect homebrewed beer?

In homebrewing, galvanic corrosion can occur when different metals are used in the brewing process, such as using stainless steel and copper equipment. This can lead to off-flavors in the beer and can also affect the overall quality and stability of the brew.

3. How can I prevent galvanic corrosion in my homebrewing setup?

To prevent galvanic corrosion, it is important to use equipment made from the same type of metal. If using different metals is unavoidable, creating a barrier between them (such as using plastic or rubber gaskets) can help prevent corrosion. Regular cleaning and maintenance of equipment can also help prevent corrosion.

4. Are there any specific metals that are more prone to galvanic corrosion in the brewing process?

Copper and aluminum are two metals that are more prone to galvanic corrosion, especially in the presence of an acidic solution like beer. It is best to avoid using these metals in contact with other metals in the brewing process to prevent corrosion.

5. Can galvanic corrosion affect the safety of my homebrewed beer?

In most cases, galvanic corrosion does not pose a safety risk to homebrewed beer. However, it can affect the taste, quality, and stability of the beer. It is important to properly clean and maintain equipment to prevent corrosion and ensure the safety of the beer.

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