Is there any way to measure/calculate/estimate the bitterness that non-hop herbs might add? I brewed a gruit, for instance, that had no hops, and I regularly add heather tips into my beers.

My Cascadian Dark Ale http://fantasmagorio.net/homebrew-recipe-black-watch-cascadian-dark-ale/

Hi everyone, I've been using the tools on Brewer's Friend for a long time, but I'm only now getting on the forums. So, howdy. I'm in West 'By God' Virginia, in the banjo-pluckin' heart of the mountains. Happy we just had a microbrewery open within walking distance of my house, run by a member...