Posting a new thread since a quick forum search for high altitude only pulled results talking about boiling. What I'm wondering is if anyone has experimented with lower mash temps at high altitude. Since water boils at 198 degrees at 7,500 feet, it seems to me that sugar extraction just might start at a lower temperature as well.
I brewed the Grapefruit Sculpin clone at 7,100 feet recently (mashed at about 155), and the result was slightly more bitter than I was hoping for. My initial thought was that the water profile in Flagstaff is to blame (very hard water), but it occurred to me that a high mash temp could have contributed as well. Thoughts?