I have never had a rubbery taste before. what are you using to ferment with? I usually start drinking mine after 2 months in the bottle. It does get better with age if you can keep it that long. I usually get a strong alcohol smell when it is just out of the secondary but after a few mins in the glass I can start to taste the other flavors coming through.
sorry i can't be much more help.
"Don't retreat - reload" - Sara Palin
Bridgeville Brewing Company