After 20 years of making pie dough, I thought I had learned everything I needed to know: Avoid it whenever possible. This education was earned the old-fashioned way, by making mistake after mistake. I have messed up pie doughs in just about every way possible.
I have made pie doughs so wet they stuck to everything they came in contact with. I have made pie doughs so dry they fell to crumbs when touched. I have rolled out pie doughs that looked like the continent of Africa (or maybe Eurasia, depending on my mood). I have made so many pie doughs that fell apart when being placed in the pan that I considered them a standard part of my repertoire. I just pinched and patched and called them rustic.
Mostly, though, I ducked the problem altogether. Ice cream? Sure. Cakes? Sometimes. Crepes? No problem. Pies? No way.
Still, I couldn't lie to myself. Sure, I could serve a fruit crisp and tell guests it was my homage to an under-appreciated corner of American home baking. Down deep I knew it was because crisps don't have crusts.
This summer all that changed. This summer I confronted my fears and tackled pie pastry head-on. After a couple of months of making two or three pie crusts every few days, I am happy to say that I have picked up a tip or two about the subject. And along the way, I learned something important.
I started by searching in cookbooks and making every pie crust I could find. I called friends and badgered them for their favorite recipes. I pumped the experts for tips. Some worked pretty well. But after a couple of weeks of this haphazard experimenting, I realized that I didn't have a clue as to why something did or didn't work. That's when I began to get serious about pie.
Pastry is really nothing more than flour, fat and water. It's how those ingredients relate to one another that determines what kind of pie pastry you've got.
Essentially, when you mix flour and water you wind up with gluten--protein strands similar to those found in bread dough. Short pastry, which is crumbly and cookie-like, has very little gluten developed. In flaky pastry, which is puffed and tends to break in sheets, there is more gluten.
This isn't just scientific jargon; it goes right to the heart of the recipe. Pastry can be made shorter in many ways, but the most basic is by making sure the flour particles are well coated with fat before adding the liquid. The fat surrounds the flour and prevents the proteins from linking into strands.
In flaky pastry, the fat should not be cut in as thoroughly. In fact, when you gather flaky pastry dough into a ball, there should be separate pieces of fat still visible. Those pieces of fat melt during baking, creating layers. (The same thing happens in puff pastry as well.)
This complicated little three-way romance plays out in other ways as well. For example, warm fat smears rather than stays in distinct chunks. That's why you get the constant admonition to keep all of your ingredients as cold as possible.
There are plenty of other issues involving fat, too. The most important may be how much is used. I analyzed several dozen recipes for flaky pie pastry and found an amazing range of ratios of flour to fat--from 3 1/2-to-1 to 2-to-1. That works out to from 4 1/2 to 8 tablespoons of fat for 1 cup of flour.
The richest crust (the 2-to-1) was very buttery, very light and shatteringly fragile. The leanest was almost a demi-puff pastry, with very clearly separated sheets of very crisp, almost tough, crust. I settled on a ratio of about 2 1/2-to-1, which is somewhat richer than normal (most crusts tend to be about 3-to-1). It seemed to best combine flakiness and tenderness (to say nothing of being buttery). And it still rolled out easily.
The type of fat makes a difference, too. Butter, of course, has great flavor. But shortening is the fat of choice for many home cooks because they say it gives a flakier crust. That was not my experience.
When I made a crust with pure shortening, it was tough and had a very unpleasant cottony aftertaste. It was less flaky and more short than the all-butter pastry, though it was not as fragile after baking. I also made crusts with various mixtures of butter and shortening. To my taste, the best compromise was about 3 parts butter and 1 part shortening. It was richly flavored and had a good puff without being so fragile after baking that it fell apart.
I also tried the much-vaunted all-lard crust and found it lacking. These days, unless you are willing to render your own lard, forget it. Commercial lard has an unpleasant chemical flavor that lingers in baked goods.
Different flours are available, too--bread flour is much higher in gluten than all-purpose, and cake flour is much lower. A crust made with all bread flour is unpleasantly tough, even hard (though it is undeniably flaky). An all-cake flour crust is crumbly to the point of being sandy. I tried several combinations of bread and cake but couldn't find one that worked as well as regular old all-purpose.