I mash in at 70 C - usually the temperature drops to 64 C - I then heat and re-circulate until mash is at 68 C. I then insulate and after 60 minutes the mash is at 67 +- 0.5 C
I then draw off 2 litres, raise to boiling point, add 2 litres and so on - always skimming off any brown scum - I cool...