It's been quite some time since I baked a pure levain from FWSY so yesterday I decided to make the Overnight Country Brown. Right off the bat I had a couple of problems. First, I use equal weights of white and whole wheat flours in my starter and keep it at 100% hydration while Forkish uses an 80% hydration starter. This was not a huge obstacle since I'm pretty good at math so I could do a conversion. My second problem was that I didn't have enough whole wheat flour to make the levain per Forkish's formula and still have enough to make the final dough, and I didn't feel motivated enough to go to the store.
Since the final dough requires only 216g of levain, I scaled down the formula while simultaneously adjusting so the final levain hydration was 80%:
Active Levain @ 100% hydration 22g
White Flour 82g
Whole Wheat Flour 27g
Water 85g
Otherwise I followed the directions without deviation. As an experient I used two different sizes of dutch ovens. One was a standard Lodge cast iron dutch oven and the other was a smaller 4-quart Emile Henry. My experience was exactly what Forkish said it would be (p. 47), which is the loaf in the smaller D.O. baked up higher with a more pronounced split. You can see the two loaves side-by-side in a photo below.
This is a delicious bread with a very moist, creamy crumb and a wonderful substantial crust. I won't wait so long before making it again.
The loaf baked in the 4-quart D.O. is on the right.