> yogurt requires a constant temperature over a specific length of time.
No it doesn't. I make perfectly good yoghurt in an old glass vacuum flask by heating a litre of milk to 80 C, allowing it to cool to 50 C, adding 60 g of live yoghurt, pouring it into the vacuum flask, putting the lid on and leaving it overnight.
> yogurt requires a constant temperature over a specific length of time.
No it doesn't. I make perfectly good yoghurt in an old glass vacuum flask by heating a litre of milk to 80 C, allowing it to cool to 50 C, adding 60 g of live yoghurt, pouring it into the vacuum flask, putting the lid on and leaving it overnight.