« on: June 02, 2013, 03:32:12 PM »
If you're adding copper post-ferment, I'd be very careful. It's a heavy metal, so it's not exactly "good for you." I read something Martin wrote about the yeast grabbing up excess copper in the wort. If you're adding it post-ferment, though, I'm not sure if the yeast will bind with it, or if you'll end up drinking it.
Here's an x-post from the probrewer forum, but I thought some here might find this helpful:
Sulfur will bind with oxidation byproducts as well. I read a study that found lagers with higher sulfur levels were more stable than those with low sulfur.
Post-ferment sulfur is probably mercaptans, and they can be removed with copper. Try treating a small amount with copper (put a penny in a glass). If it's mercaptans, the smell will disappear immediately. If not, you've got sulfides, and if so, good luck.
To avoid producing excess H2S (which later form mercaptans, then sulfides/disulfides) in the first place, ferment at a lower temperature, provide necessary YAN, select a low-sulfur yeast strain.
Running beer through a copper tube or something is kind of a WAG approach to sulfur removal. You don't really know how much copper you're adding when you do that. Wine guys use titration bench tests with copper sulfate solutions to determine the exact amount they need to add. The copper sulfide you create after the sulfate reacts with the mercaptans will settle out over time, and you should remove it if you can. So fine, rack, filter or all the above.
For dealing with sulfides, well, you should probably just give up. There is a hail-mary approach, though: in the absence of oxygen sulfides will revert back to mercaptans. So you can use asorbic acid or similar antioxidant to try to knock out the O2, then treat with copper. But, that's not a sure or fast way to do it.