take a good porter recipe, something chocolatey would be best, add the bean or a little extract/essence to your secondary fermenter, and leave it in. i haven't used beans cause theyre expensive, but one or two is good i think. try a recipe with a 1/2 lb. crystal 80-120, a lb. of chocolate malt, 4 oz. black patent and about 5 lb.s of your choice of extraxt, i'd go amber or dark, but some peoople like to use light for everything.