I want to make a pecan porter using fresh pecans. I've never used nuts in a beer before and I'm not sure how much to use and if I should add them to the mash or in secondary like if I was adding oak cubes and age on the nuts for a while. I would like the beer to have a nice pecan aroma and flavor, but not overpowering. Any ideas? Oh, and it's for a 10 gal batch.