Brewed my grist all grain batch the other night which was supposed to have an OG of 1.077 and wound up being a 1.038. I could not figure out what the deal was so I bought a new thermometer today and it turned out my original one was a little more than 20 degrees off! Talk about a sigh of relief and a bummer all at the same time. I was using a candy thermometer which proved to be fairly accurate the past few brews, but I haven't bothered in using it in several weeks. Just let this be a lesson to anyone deciding to start all grain... Get a good thermometer.