Immersion cooler question

I made an immersion cooler out of copper tubing, when I put it in my wort to boil for the last 20 minutes, it tends to leave a small metallic looking film, is this unusual, should I be worried about it? I use an aluminum brew pot.

Thanks

It sounds like you didn't rinse the machine oil of it.

Sorry, I forgot to mention when I first made it I boiled it in 50/50 white vinegar and water, I thought that'd clean it off.

Yep it should of done. Can't think of any other cause.
How do you clean it after use?

I usually put in a bucket with bbrite and water soak it for a bit then rinse it in the shower.

Could it be the combination of aluminum and copper? Our house is aluminum wired and we can't use copper wired fixtures because of a chemical reaction that happens between the two metals. Wikipedia says "galvanic corrosion can occur in the presence of an electrolyte" Perhaps wort acts as an electrolyte?

This is sort of what I was worried about. The same thing has happened the 4 times I've used it no matter how clean it is. But I figured if this was a common aluminum/copper problem someone out there must've seen similar results...

I had one more thought on this, if this is really due to a copper / aluminum reaction and I get the metalic film when I'm brewing beer wouldn't I get the same film when i'm cleaning it with 50 /50 white vinegar and water because of the acidity of the vinegar?

MariaAZ said:

Could it be the combination of aluminum and copper? Our house is aluminum wired and we can't use copper wired fixtures because of a chemical reaction that happens between the two metals. Wikipedia says "galvanic corrosion can occur in the presence of an electrolyte" Perhaps wort acts as an electrolyte?

Click to expand...

Maria is right. galvonic corrosion!!! save up for stainless steel.

If its galvonic corrosion is it safe to drink the current batches?

And how is it that everyone who uses an aluminum pot doesn't have this problem??

I'm quite familiar with galvanic corrosion, and while these 2 metals are classic corrosion parties Al being anodic anywhere from 6 to 26 depending on alloy with copper being the cathode at 33. See http://www.corrosion-doctors.org/Definitions/galvanic-series.htm for the whole table. You can determine the galvanic potential with a voltmeter between the 2 metals with .15 volts or less being acceptable, the higher the voltage the greater the potential for corrosion to take place. If it is a concern, you can electrically attach a vessel of saltwater to the copper and immerse a zinc cathode in the water which is connected to the Al pot.

All that being said, it isn't a concern in the limited timeframes we work in.

I've been brewing in aluminum for many, many years and have never observed this problem.

And that is all I will say.

Fiery Sword said:

I've been brewing in aluminum for many, many years and have never observed this problem.

And that is all I will say.

Click to expand...

The pot that you have Fiery sword I'm guessing is made in the USA and is probably made from different componds of the alloys. The one that BernieBrewer has since it is newer is probably made in China and is made of diff. componds this maybe a factor? I say do a test and and brew a batch with SS.

BernieBrewer said:

I made an immersion cooler out of copper tubing, when I put it in my wort to boil for the last 20 minutes, it tends to leave a small metallic looking film, is this unusual, should I be worried about it?

Click to expand...

I am hardly an expert, in fact I just have a couple of batches under my belt (so take this with a grain of salt). Is it common practice to put the cooler in while the wort boils? I put mine in (scrubbed and sanitized, of course) after I turn off the flame. Could the boiling of your cooler have something to do with this?

Am I doing it wrong?

Good luck!

Most of us (I thought all of us, until you posted) add the wort chiller with 15 minutes or more remaining in the boil. That much time in boiling liquid will sanitize the chiller.