I need to buy a banneton, I use a lot of recipes from Ken Forkish's Book, FWSL.
He says to buy a 9inch banneton, can I buy a 8.5inch or 10inch, the 9 inch don't seem as common?
Also real bakers talk about bannetons by weigh. Which is the best multipurposed used size?
Buy the smaller one. High hydration breads tend to spread out and flatten so a narrower banneton has a greater ability to control the spread. Also, if the height of the rise in the banneton does not reach the rim then the dough tends to drop out of the banneton when flipping it over onto the baking stone which also causes the dough to flatten out.
This purchase is most likely one of many for you, so it is a starting point and later on you will add other shapes and sizes to the bannetons you own, so don't over think it.
Frank
as the 9inch? or should I get the 9inch like the book says?
I'd only add that you may want to buy two as the larger recipes in his book will make 2 loaves. Also, I usually prefer the oval shape as it works better for sandwiches.
FWIW, I happen to be rather cheap and found EBay to have the best prices including shipping. In fact, the one that I bought with a nice tag was identical and guess they just bought in bulk from China and repackaged them.
Oh yeah, make sure they come with a liner.
You need two bannetons and liner's are really helpful with high hydration formulas. 8.5" ID banneton is for a 1.5 loaf.
I meant 1.5 lb loaf.