Put milk, sugar and vanilla of choice in TM bowl (if using bean, scrape seeds into milk). heat for 12 mins, 80 degrees, Speed 2.
Whisk for 10 secs, speed 4 until a light foam appears on the surface to avoid skin forming whilst cooling, remove lid and leave to cool (this process will take approx 1 1/2 hrs, so set a timer)
Test temperature by placing bowl in TM and turning on...if 37 degree light is on it is probably too hot. wait for light to go out or test like baby milk on your wrist before proceeding.
Add natural yogurt starter, mix gently speed 4, 4 secs. Heat the yogurt base for 10 mins, 37 degrees, speed 2.
Meanwhile boil kettle and place oven on a low heat approx 50 - 70 degrees to warm up (on warm summer nights you can just leave out). Fill Thermo server with boiling water to scold out, then discard the water and place lid on to retain heat until ready to use.
After 10 mins cooking has completed, pour warm yogurt mixture into the pre warmed Thermoserver or flask equivalent. Wrap server in Thermo mat and teatowel to preserve heat during incubation and place in oven or warm place for 6 - 8 hrs or overnight.
After time has elapsed and yogurt thickened, strain through muslin until between 200-400mls of whey has been strained off to get a creamier thicker consistency.
Chill and serve.