I'm not having much luck finding any plain pastry flour at my local grocery stores in Seattle but I'm finding whole wheat pastry flour pretty consistently. Is there a difference?
Yeah. One tastes like Whole Wheat! You can order King Arthur Pastry Flour on Amazon, or their website.
To expand on this a little, pastry flour (and cake flour) have a lower protein content, or less potential to create gluten. One way to do that is to keep more of the bran in the mix, as in whole wheat. You get to list a single ingredient and it seems more "natural" or "whole food" or whatever.
The alternative is to source softer wheats and blend in other things with less gluten. King Arthur Pasty Flour is a blend of soft wheat and malted barley. The malt in the mix contains enzymes that convert starches to more sugars, which give more food to drive yeast activity, and more browning in your oven.
The recipe for croissants in Bouchon Bakery cookbook uses AP flour, but calls for the addition of diastatic malt powder for the reasons above.
I prefer to use things marketted specifically as white pastry flour and am not put off by an extra one or two ingredients on the label.
