So I've done a couple of partial mashes now, following Deathbrewer's stove-top method (using the kettle as a mash tun), but have encountered some weirdness with the temperature stability. For example, the recipe called for 155° mash temp, so I heated up water to 167° (because of 11-12° loss). I added the grains, stirred thoroughly and checked temp with the floating thermometer, which showed 156° or so. I left the thermometer in, put the lid on and wrapped it in a towel. Came back 10 mins later to check, and the temp was into mid 160s, so I added a bit of cold water stirred again, etc., but on next check the temp was up again. Any idea why this might be happening? I'm pretty sure laws of thermodynamics don't allow this unless the amylase enzymatic reaction releases heat.