Off flavor when beer is chilled

Hello,

I hope someone can help me with this issue that I have noticed in some of the beers I have brewed, including my current batch of American Amber. For some reason, the beer seems to develop an "off" flavor, sort of an undesirable (not hoppy) bitter aftertaste when chilled. However, this flavor is not present or greatly subdued at temperatures closer to room temperature. This also happened to an IPA I brewed and at least one other batch I have made. Each batch was brewed with extracts and bottle conditioned for 2 weeks or so before being chilled. Does anyone have any idea what causes this?

Thanks for your help!

More than likely your water if you're using tap water. I'm suprised you don't notice it when the beer warms up though. Most time, off flavors show up better with warm beer. Either way...I know what the bitterness you're describing is. It took me a year to figure out where it was coming from for me. I changed everything in my procedure except for my water. When I finally went to straight RO water with minerals added when needed, it went away.

Thanks, that gives me a good place to start! I did use tap water, but I wonder what specifically in the tap water causes this? For this batch the water was tap water, but it went through a "pur" faucet filter before use.

I suggest reading "How to Brew" by Palmer. He's got some great info about water in there.

Basically, every grain will react a little differently to the pH of your water. If you're making a darker beer, you'll want a very hard water. The opposite is true for lighter beers. It all really depends on the style of beer you're brewing. That's why some of the best beers can't be reproduced by homebrewers unless you adjust your water chemistry.

double post

Grimpond said:

Thanks, that gives me a good place to start! I did use tap water, but I wonder what specifically in the tap water causes this? For this batch the water was tap water, but it went through a "pur" faucet filter before use.

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High levels of bicarbonates in the water can cause an astringent bitterness in beers. Higher hop bitterness will accentuate this. Water filters will not remove bicarbonates.

Filters will not remove all the alkaline particles either. My tap water tastes great when filtered through a 0.05micron filter. But after it is stored a few months the alkaline flavor comes back.

I just switched to spring water because of this discovery.

Thanks for all the insight and advice. I have used spring water before and I guess now it is time to switch back!