Pinning down off-flavor...

Last summer I switched over to kegging and ramped up the brewing throughout the year. I brewed many batches and got beer into kegs for long term conditioning. I have been going through them and all my beers have an off-flavor. With beer that was conditioned so long, I was surprised it had such a bad taste.

I would describe it as a metallic/tinny/alchoholic type flavor. Most of my beers are lighter ales. The flavor was in a few stouts I did, but it was covered up some.

I made some changes to my brew process last week, and the off-taste is very strong in the 1 wk old brew. The off flavor was not there when I tasted the beer before fermentation started, so I am wondering if this is a fermentation problem.

I pitch the dry yeast around 75 deg and it ferments around 70-72 in a closet with no light. The yeast I used last week was ale yeast, which needed to be pitched below 80, and ferment from 65-75.

Any ideas what could be causing this? It is very frustrating to keep tossing beer.

My process
SS pots (I have 2, have used both)
Bottled water (from Food Lion. Also used tap water and taste was there)
Steep Grains at 155 for 30 min (when called for)
Cool beer with copper wort chiller. Tried a bag of ice last week right into the wort in case the wort chiller was giving off the taste.
Ferments in a back room closet, temps stay from 70-73.
I have left many brews in primary for 3-4 weeks, skipping secondary on some. I went back to secondary on the last few and off-flavor still there.
I use star san for everything.

The one week old brew is way too green to use for comparison testing right now I think - it could just be green beer flavor that you are noticing in that one.

When you say that it ferments around 70-72, is that the ambient temperature? The alcoholic flavor could be coming from fusels if the temperature is too high. Generally, the temperature of the fermenting beer will be higher than the ambient temperature by 5-10 degrees.

Metallic flavors can come from metal (insightful, right...?) although the stainless steel shouldn't be causing that. Perhaps the copper, and given that the test batch is so young I think that is still a possibility. Do you have really high levels of iron in your water by any chance? That is another possibility. According to the off-flavor chart at Morebeer (see here: http://morebeer.com/themes/morewinepro/mmpdfs/mb/off_flavor.pdf) it could also be from improperly stored grain, although I haven't experienced that before myself.

boydsbitchinbrews said:

When you say that it ferments around 70-72, is that the ambient temperature? The alcoholic flavor could be coming from fusels if the temperature is too high. Generally, the temperature of the fermenting beer will be higher than the ambient temperature by 5-10 degrees.

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I gotta agree with you there. Pitching at 75 and fermenting with an ambient temperature in the low 70's will almost certainly throw some fusel off flavors. Every beer I brewed before temperature control tasted awful when put right next to one with controlled temperature. The beer was drinkable but noticeably worse.

Metallic taste can also come from beer being green. I've noticed that exact flavor disappear after a few weeks of conditioning.

Definitely sounds like a temperature issue if all your beers were in an ambient temp. of 70-72. I had the same experience as the last poster in that my beers before temperature monitoring and control were not nearly as good after I started paying attention and taking measures to control my early ferm temps.

You say you dumped a bag of ice directly into your wort to rule out the copper? That could very well cause infection and off-tastes, so I wouldn't do that anymore. I doubt it is your copper WC anyhow. Get your temps down to 60-65 ambient and see how things turn out.

Most of the time we over think our problem with off-flavors as being something in the process, but it usually comes down to contamination. Process off flavors are generally something you'll recognize in commercial micro brews because every ones process is a little different. Normally if it's an off-flavor you recognize you'll say: "hay it tastes like..." but if it's repugnant Look at sanitation, it can never hurt.

Thanks for the replies. I know the week old beer is green, but it has that taste that the 8 mos old one does, and it did not when I transferred to primary.

It is frustrating, I started brewing with my dad 15 years ago and all was good. Stopped when college hit and picked it back up a few years ago, and now its a strain of this same off-flavor.

Ive tried different kits from many different companies, my buddy started brewing this year and did some of the same ones I did. He even commented mine tasted different. We did 3 of the same. I cant imagine 'bad grain' stretches across all these companies and the LHBS.

I think I am going to try to brew next week and and stick the carboy in water with a towel/fan to get temps down. When controlling fermenting temps are others just using a small fridge/freezer with a controller?

I am wondering if you cleaned your kegs before you used them and if they were new? That can add metallic flavor too. I am wondering how long your leaving these light ales to age in the kegs and what they were because that can do the trick too. Are you doing water adjustments also or just solely using the bottled stuff?