Hi everyone! I’m struggling to perfect my pain de mie. I have two Pullman pans, one 4 1/2 X 16 1/2 and another 5 1/2 X 10 1/4 - neither of which are the size required by Rose’s recipe or any other I’ve come across. Does anyone have any suggestions on how to arrive at the amount of dough for my pans? Thanks!

I did this exact thing about a year ago, but I think it took me a couple of tries to get it right.  I wish I had taken better notes—I wrote out too many calculations, but I think what worked was a simple volume ratio.  You need three figures—I will assume your width and height are the same.

Original: 4 x 4 x 16 = 256
Pan 1: 4.5 x 4.5 x 16.5 = 334.125
Pan 2: 5.5 x 5.5 x 10.25 = 310.0625

Recipe for pan 1, multiply by 1.31 (round to one and a third if working by volume)
Recipe for pan 2, multiply by 1.21 (round to one and a quarter if working by volume)

Obviously, this is easier to execute if you are working by weight.

Thanks Matthew! But just to confirm I understand you correctly, are you suggesting that I calculate the volume of the pan and then adjust the ingredients proportionally? I’d always understood with baking that you couldn’t necessarily simply halve something and get the desired result - but maybe I’m wrong?

Cakes are the only thing I am aware of that you can’t always scale, but only because of the different levels of chemical leavening (soda or powder) needed for various pan sizes.  I think anything else made at home can be scaled equally—when you get to commercial-level quantities, however, some of this changes.  Can anyone think of another example?  Anyway, it works just fine for breads—I do it all of the time.

Btw, the only thing that will be challenging for scaling bread is calculating the salt and yeast—two ingredients everyone mostly measures by volume.  I recommend you calculate the weight of a very small unit (1/8th or 1/16th teaspoon) and then calculate the scaled up volume using that figure—-or you could just use the rough suggestions from above—increase by 1/4, etc.