I'm hoping someone can explain the term " mash in". I've been brewing for a while now and I thought I understood what it means. I've always thought it was the act of adding the water to the grain at the beginning of the mash in the mash tun. But as I was reading Mitch Steele's book about brewing IPA's, I read in the recipe section for DuganA where the brewer mashes in at 50 minutes. What? What's going on for 50 minutes before you add grain? "Mash in occurs at 50 minutes, rest at 20, vourlaf at 15" hopeing someone can explain this. Thanks!!