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Helping wih an off flavor

G

ggltd

In my last 3 brews I am picking up a slight off flavor.  Some of the neighbors do and don’t taste it. To me it’s like a “dirt” from the potato patch- I wouldn’t call it metallic, but my one buddy got that. It’s enough that I won’t serve or drink it.  First I dumped all my yeast starters, scrubbed everything and started over.  No luck. So working through the possibilities I narrowed it down.  I brew and ferment in stainless. Could too much StarSan left in the fermentor leach out the metal taste- if so can I fix this? I ferment in a ½ keg- it’s hard to scrub it out. Or is it my copper manifolds in my mash tun and boil kettle that are doing the same thing?  Or a crazy infection somewhere through the process?  This one’s got me nuts and I have already dumped 20 gallons of beer.  I never had this problem on my old system of a 60qt cooler mash tun and glass carboys.  Thanks everyone.
 
Not the most experienced with this but I have read that if Star-San is left too long in stainless it may cause damage. I have also read that the use of copper over time can cause issues as well, you may want to pose this to the folks on the AHA forum as well as that is where I read about the issues I bring up, good luck, sucks dumping beer..... :-[
 
Could you describe the flavor as "rust" like?
Is there any metal that comes in contact with the brew that could be oxidized but difficult to reach? (no suggestions on cleaning it. just trying to brainstorm on what the problem might be)

Have you found any rings in fermenting vessels, bottles or kegs that were not obviously caused by yeast?
I've had a few infections and they were always accompanied by rings that did not clean easily.
The way I got rid of my problem was to only ferment in glass, and to ruthlessly sanitize any plastic that comes in contact with post-boil brew.

Have you tried your local homebrew supplier?
Perhaps bring a sample?
 
If it is bacterial, I would look at replacing bungs that are not still smooth and rubbery as well as hoses.  What is kept should be soaked for 30 minutes in hot tap and PBW.  Not just oxyclean (PBW has a cleating agent as well as a surfactant to get into the places where bacteria hides).  You can bleach them too in a 5-10% bleach dilution.

Starsan left too long in stainless will pit it eventually.  You should let it dry out.  The pits will quickly oxidize though and will not leach metallic taste. 

Metallic or earthy flavors can come from hops.  This will quickly fade though.  What styles were brewed?

It can come from a wild yeast too.  Take a finished sample and measure the gravity with a hydrometer over a month.  It should not drop.

Real metallic is unmistakable.  Get a piece of non-stainless wire and soak it in a beer overnight.  Taste it.  You will know what metallic is like when using non-stainless somewhere.

 
Hi everyone and thanks for all the good suggestions.  There was one other that my buddy mentioned and that is how I am storing my bulk grain.  I try to put it all in a sealed plastic container but sometimes just roll up the 50 lb sack real tight and store it in a wall cabinet. This might also be part of the problem. So my plan is to remove the copper manifold in my mash tun, and try to find some better storage for my grain.  Does anyone keep small leftover grain in a freezer?  I also have been doing this with sealed bags.
 
Look for something that changed in the brewing of the first dirt-flavored batch and is common to all three batches.

My first guess for a dirt-like flavor is just that, dirt. Have all three of the affected batches been brewed from the same bag of base malt or contained other ingredients from the same bag?

My second guess is that there's some mold hiding somewhere in your system.

My next-to-last guess would be contamination from your water.

My last guess is grain spoilage. I order my grain crushed and store it in a plastic tub. I don't think the lid is air tight, so I put a package of desiccant in the tub to absorb moisture - I'm 100 yards from a bayou in Northwest Florida, so we have plenty of moisture. So far, the grain seems to be keeping well. In the past I stored my bulk grain, uncrushed, in the original, double-wall paper bag on the floor of the pantry for at least six months. It did not develop any odd flavors in spite of humidity and temperature variations from 65 to 90 F.

Good luck tracking this down. Please let us know if you find the culprit - or if it just goes away.
 
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