An update from me on Mash efficiency, I'm getting good results now after a poor start, and I think I've pretty much nailed single step infusion mashes now, so thought I'd share my experience. I've always been a bit wooly on sparging, some places say you need to sparge with 78C water, other suggest temps 90C and above.. The temp depends whether you mash out or not, the target is to sparge with the grain bed at 78C but not over (Over 78C washes tanins out of the grain which can negatively affect taste)/ If you perform a mashout then your grain bed will already be up to 78C therefore you'll sparge with 78C water. If you don't perform a mashout, then you'll need your water hotter than 78C, and the temp depends on your bed temp and mash tun shape. Basically, experimentation is the key here. Now this next bit, everyone should do this. I set a couple of temp probes up tied to the bottom of my mash tun(ish, about an inch from the bottom of the grain bed) and left one right at the top. My tun is a bit on the tall side and has a thick grain bed as a result, probably a bit too thick. I found that heating my water to 75C meant it was around 71 - 72C in the tun, then by the time I had added the grain and doughed it in the temp was pretty much bang on 69C. I find that 2.5L to every kilo (+3L headspace for my tun) works well, and I spend 5 or 10 minutes doughing in and breaking up dough balls, experience has taught me that this makes a massive difference in efficiency. I stirred every 20 mins or so, the mash temp dropped 5 degrees over the 75 min mash (My tun could do with better insulation really). So I started with 78C water, but quickly realised it wasn't hot enough. I increased the temp to just over 90C and as I slowly drained the tun, sparged with 90C water, by gently pouring it in with a jug over the top of the grain bed, keeping the water level just above the top of the grain bed. Throughout sparging the grain bed absorbed the heat, the top stayed below 80C and the bottom lagged behind, eventually they equalised around 78C at the end of sparge. I collected 30 litres, and after boil was left with an extra litre of wort (24L) at over my target OG! This is a great result for me, and the extra temp gauges really gave me a window into what was going on at sparge. The temp gauges I use are cheapo LCD ones for �£2 each off ebay, I'd recommend checking them (Because they're so cheap), mine have all been fine but better safe than sorry. check them at 0C in ice water, then again at boiling point in a kettle.