metallic taste

i am starting to have a metallic aftertaste in my beer that has been in the bottle longer than a few months. been brewing faster than i am drinking it any ideas what i can do besides drinking faster? i already use oxygen absorbing caps

Does the beer taste fine until a certain time? I know you said its been in the bottle for longer than a few months, but, are you drinking some of that batch and then after a while the rest of it starts to taste bad? Has the beer been sitting for a long time in the bottles before you even try one? Where are you storing it? Is it subjected to large temperature swings or exposed to light?

I'm just firing off questions from the top of my head to try and narrow it down.

the beer does taste good at first. it usually sits in the bottle for two to three weeks before i try one.two or three months after that it starts getting metallic taste to it. the beer is stored in my basement. it stays pretty steady at 60 degrees and no light gets to it.

Hmm...how is your water? Also, are you using an aluminum pot? Make sure if you are that you do the 30 minute boil.

I've noticed the same thing in a few of my dark beers. I saved a few of my first brews and cracked them after 8-10 months and they had a distinct metallic taste that was not there before. They were all grain brews using unmodified bottled spring water. They all tasted great at first and they were still palatable later but there was definitely an off flavor.