Lookin' Through a Window Pane
Many bakers talk about "pulling a windowpane". Why do we want a windowpane? What IS a windowpane? And how do we create one? And, does it really matter all that much?
As Roseann Rosanna Danna used to say on an early season of Saturday Night Live, "You ask a lot of questions for someone from New Jersey!"
We want a windowpane because it is an indication that your dough has been developed enough. It is a better indicator for simple doughs than for doughs with added seeds, nuts, fruit or other flavoring agents. Despite nay sayers, you can create a windowpane with whole wheat doughs. A long term benefit of a windowpane is that when you create a windowpane with simple doughs, you'll know how your dough should look and feel even if the dough is loaded with other ingredients.
A windowpane is the result of developing the gluten to the point where the dough can be extended, or stretched out to the point where you can see light through it without the dough tearing. With very liquid doughs, this can be as simple as grabbing the dough and lifting it from the mixing bowl. With firmer doughs, it can be more difficult.
Let's talk about firmer doughs which aren't going to let you just pull them from the mixing bowl. Once a dough you are working on is springy and lively, it's time for what bakers call "the windowpane test". Start by pulling off a piece of dough about the size of a walnut. Roll it between your hands for a few seconds to smooth the damage done when you pulled the dough away from the larger chunk of dough. Now, using both hands, pull the dough between your hands. The idea is to tease the dough into a sheet or film. From time to time, rotate the dough 90 degrees so you will be pulling on different sides. As you pull on the dough, it should form a sheet, or film, that is thin enough that light can pass through it. No, you won't be able to see things through it, like you could with a real window. The dough shouldn't tear when you do this.
If you can form a windowpane, the dough is fully developed. If you can't, then knead another 5 minutes or so.