In another thread Tom Schmidlin mentions that beer coming in contact with copper can produce off-flavors quickly.
But, many, including myself, brew in copper. Can someone elaborate? Tom?
I’m certain more detailed information will follow, but it’s when copper comes in contact with beer, not wort.
So, brewing in copper is fine (obviously since it’s been done for centuries). Fermenting/serving in copper is where you can get off flavors quickly.
I’ve never heard that copper imparts off flavors in wort.
I think you nailed here. My father-in-law gave me a set of these very cool copper beer mugs. I use them every so often, and the beer certainly tastes different in them. Although, I kind of like it from time to time…
Although I don’t know if this is the case, here is my theory. Copper is highly reactive. Finished beer has significantly lower pH then wort (mid to low 4’s vs mid to low 5’s). It is possible that this could be the cause of the problem.
The Pilsner Urquel brewery used to be (and may still be) an all copper brewery which leads to considerable copper pick up. Some will also note that copper is used in fungicide, however I have never heard of brewers having problems with yeast health due to copper kettles, lauter tuns, ect.
Hence, it appears that copper pre ferment - good, post ferment - bad, and I would guess pH has something to do with it.
Yes, the pH drop as the beer ferments will cause the pick up of the copper. Copper immersion chillers will come out of wort with a bright shine. Think of what the more acidic beer will do.
I know one brewery, I forget which, had a problem when they went all stainless. The problem was remedied by inserting about 3 feet of copper in place of some stainless pipe. It was a micro-nutrient issue.
Yes, like several people have mentioned, I believe it’s the pH drop that makes it a problem for beer but not for wort.
I’ve heard the same story as Fred, and I know copper is a required co-factor for several enzymes important for yeast health. Going all stainless probably won’t be a problem as long as you’re buying your yeast, but if you’re repitching it can become a problem after a while (I don’t know how quickly, haven’t tested it).
I have heard of homebrewers throwing pennies in their kettle for this same purpose. Although now a days I think pennies are almost all zinc and only a little copper - (zinc is obviously also an important micor-nutrient so no harm there)
I remember reading that in JP’s HTB. I think he was suggesting it not only for yeast micronutrient purposes, but also to serve as nucleation sites for boiling wort (and to help prevent boilovers).