I decided to make a sourdough starter about 4 months ago following the recipe in Betinett's "Crust" book.
I made it up, fermented it as prescribed then baked my first loaves with great success, refreshing the remaining ferment and keeping it in the fridge. Not baking the bread very often, I refreshed (or fed) the ferment about once a week. The next time I baked some bread it was incredibly slow to prove (the baked loaf was dense after a 20hr prove), so I decided to allow the ferment to become more active, keeping it at room temerature for a day or so. After this, I continued to refresh it every few days, and keep it in the fridge. It was now noticeably more active and the next batch of loaves I made overproofed to the extent they had almost become liquid. Needless to say I couldnt turn them out to bake and had to throw them away. I have since made successful loaves out of the ferment, but it seems to be very active to the point it's climbing out of the bowl even in the fridge. Once I refresh it and put it straight back in the fridge, it doubles in size overnight and needs knocking back.
I really want to slow it down a bit and make it a little less active, so does anyone have any advice on how to achieve this?