I've just followed the Dan Lepard 7 day sourdough starter recipe. I had tried once before but nothing was happening and I think that was because it was very cold (it was snowing outside) I had the starter on my windowsill so it was very cold there. It was probalby very slow to start and I gave up thinking it was not working. When I tried Dan's recipe I kept the starter in the cupboard the boiler is in, so it was warmer but not too hot either. Although it started off slowly by Thursday (day 7) it was at it's peak, bubbling to the top of the jar and almost escaping. I fed it again, then the next day noticed the bubbles had dropped, although though it was still bubbly. I thought this meant something was wrong so I fed it again and put it in the oven at 100 degrees, but I turned the oven off so once it had reached 100 degrees so the temp never went over 100 degrees (which I have read will kill the starter). I kept it there for about 5 hours then reapeated the process. This morning it's totally flat, with some hooch(?) smells fine, but no activity at all. Now I'm thinking the heat may have killed it off a bit. My instinct, from everything I've read is to start again, reserving 100g of the starter and feeding it with 200g of water and flour until it reaches it's peak again. What I don't understand is why it peaks then is it bad if it goes past it's peak? Could I have still used it to bake bread after the peak was passed?