Does metallic only come from rust or can it be from yeast? I have a keg that has a bit of a penny taste. Not the faucet as I swapped kegs. Yeast was 4th gen Rustic/3726.
Is it a dark beer? You may need to passivate that keg.
Nope. 3-4 SRM. It’s a new keg, so a bit of a bummer to need maintenance right off. I’ll break it and the faucet down once it kicks. If there is no visible rust, I’ll see if I can get the shop to send me a replacement beer tube.
What’s your homebrewer SOP? Double strength Star San?
Is it a Belgian per chance? I have seen metallic flavors thrown early after/right before kegging. Cleared up after a bit, weird stuff.
I’ve never passivated with Star san before but it is an acid so the right concentration may work. New stainless often needs passivated from the manufacturer. We use double strength acid wash for ab out 2 hour cycle, then don’t rinse but let air dry over night then rinse the next day and sanitize.
I’d have to check when I get home, but I believe SS Brewtech specifies 1 ounce of start san to 1 gallon of water for passivation. As majorvices said, rince with solution, let air dry, then rinse with water.
Bar Keeper’s Friend is easier to use though. SS Brewtech recommends the star san method as BKF will remove their etched volume marks over time.
Thanks. BKF won’t work for a corny keg (can’t reach the bottom). I’ll check SS brewtech’s site to see what they say.
ETA - you’re right on the one ounce per gallon with 20 min contact time. I’m lazy so I’ll fill the keg. Should have bought the big bottle of Star San
It’s a lighter beer made with Imperial Rustic which is said to be Wyeast Farmhouse. Been in the keg for two months, so I don’t think it’s going away.
Frequently a sign of oxidation
I’ve found that some water profiles can throw off low-level metallic notes as well.
Water is pretty simple based on Jever boiled. This was a split batch and the other keg with WLP029 doesn’t have it.
While I won’t rule that out, my cold side practices are pretty solid.
One thing I’ve noticed is it is more pronounced when freshly poured and reasonably carbonated. If I neglect it for an hour it’s much less noticeable. The CO2 is for sure enhancing it. Maybe the acidity of the gas in solution. Can’t be the gas itself as it is shared with 3 other kegs.
I think you’re on the right track thinking it’s a keg issue. I had this happen, traced it to a particular keg, ended up being rust in the dip tube.
I’ve noticed some people mistake low oxygen associated darker malt flavors as being metallic, especially in Guinness and Newcastle Brown, but I don’t see that being the issue here.
If its a split batch with different yeasts and the other keg is fine, sounds like the yeast. Although I agree with Denny, I usually associated metallic off-tastes with oxidation.
Four generations of farmhouse yeast may have picked up something along the way, in terms of mutations, infections, etc. I’ve done up to 6 generations of lager yeast, and have noticed that the later generations were not as squeaky clean as the first couple. Now I tend to stop at three.
That’s why I was suspecting the yeast at first. It’s odd as it feels like it belongs if it were more subtle. All my searches pointed to metals, not a one mentioned oxidation or yeast.
I’m with you on high carbonation enhancing/causing a metallic flavor in beer.
The beer is only at 2.5 vol, same as all of my other kegs, so I don’t think the carbonation is the cause.
I’m brewing this weekend with Rustic so that will tell me if it’s the yeast.
I just bought Rustic this weekend. Will be interested in this.
I didn’t get it until this batch. I’m leaning towards the keg.
What if one keg needs passivated and one does not? Metallic flavors, except for in some cases of dark beers at very cold temps, almost always indicate metal got into your beer somehow. Either through the water or though an item that is in need of passivation.
Also, every passivation process I have ever done say drain the acid, but don’t rinse for 24 hours.