Matt, I have been making doughs recently, with the young levain method that the tartine bread book has emphasised. I noticed recently, that as opposed to my not so young levain that I used to use for doughs, I am getting more fermentaion activity in the fridge if I decide not to use a room fermented dough on the day I planned and hold it in the fridge. It used to almost stop, but now keeps going. I have not decided to do a cold fement, but maybe its worth a try. Overall, the young levain approach has been helpful for all my doughs. Just my thoughts. -marc