I've made 8 batchs of AG rye so far, screwed up each step, haven't mashed right yet, drank them all. Well, one is in bottles, one into the fermenter today. My feeling is that the temps quoted are ideals, not that critical. Todays batch never did get to 150, my OG was 1.061 anyhow. Seeds don't get to 150 either, yet they sprout and grow just fine. And, drying and roasting certainly exceed 170, yet yeast still makes strong drink...Lighten up, have a brew, look forward to somehtin different.