Do you chill your wort before pitching your yeast? I no longer use the the Mr Beer keg for fermentation. I brew 5 gallon batches. I use a food grade plastic fermentation pail. I chill my wort before pitching the yeast. The chilling will stop any cooking and prevent further tannins being released. I keep the wort in the fermentation pail for 5 to 7 days. I then rack off the wort into a 5 gallon glass carboy for the balance of conditioning time. I have found this process helps in the fining of the beer. Make sure you use good sterilizing practices when using your airlocks. SO, I buy double the product when brewing Mr. Beer recipes.