I've baked about a dozen loaves out of Ken Forkish's FWSY and as he suggests in the equipment section a 5qt dutch oven produces a flatter loaf. I've been unable to get his splits and ears and my loaves are shaped more like saucers. He specifically states that a 4qt pot works better for this. And while I could order one, I'm lazy, so I thought, "What if I scale up the recipe to 1500g flour for two loaves?" And I now have a rather large amount of dough retarding in the fridge for a bake tomorrow morning.
Anyone ever try this? Do I need to adjust my bake times to compensate for a 50% larger loaf?
The loaves I've made taste great and when I get the proofing correct have a wonderful open crumb, but I'd really like to be able to achieve the crusts and spring that he has in his photos. The bigas and the poolish based white are my favorite. The later of which I do with a retarded bulk overnight in the fridge(so roughly 36 hours from poolish mix to shaping).
bake time, in my opinion. I've scaled recipes up to fit my DO, just as you are doing and found that they were underbaked. I turned the temp up and burned them, so I turned the temp down and baked them longer and it worked perfectly for me.
I scale up the dough between about 1.5x to 1.75x and bake 5 to 7 minutes longer.
FWIW, when I baked in DO I always went with 500g of flour for 5 qt DO. Of course, you need to consider shape - Forkish says his 4 qt DO is 10" at the top and 4" deep, and my 5 qt DO is 10" at the top (8" at the bottom) and ~5" deep, so while they may have different volume, the only real difference is height.
As far as baking goes, the general rule is that as your loaf gets larger you need to lower baking temperature and extend baking time.
The results were much better with more dough. I baked two loaves prebaked weights were 3lbs 4oz and 2lbs 12oz. Did 35 minutes with the cover on then 45 minutes off at 475deg. Overnight bulk fermentation followed by dividing and returning half to the bin, shaping and proofing while the oven preheated for the other. Although the dough was so cold I don't know how much proofing really happened, but it's much easier to shape that cold dough. Shaped the second when the first went in. It got more proofing as I put it above the oven where it was quite warm.
Much better oven spring. The second one split in a manner much closer to FWSY's photos. The first I scored and it expanded nicely.
The lesson of this experiment is that dough volume to dutch oven size matters. A ratio based off of 750g of flour at 75% hydration for a single loaf works better in a 5qt lodge than Ken's 500g size.