Pie crust with pecans: a tough nut to crack

Maple-caramel apple pie with a pecan pastry crust. Delicious AND nutritious!

I friggin’ love pie. It’s not just because a good pie contains upwards of 3 sticks of delicious, nutritious butter. Despite its down-home reputation, pie can be a deeply complex dessert (or a stew-based meal). A good pie is a study of contrasts in texture and flavor. And a good crust is the platform for a good pie.
Some backstory: I wanted to enter—and win!—Chicago’s Bucktown Apple Pie Contest. I had already developed a fancypants “maple-caramel apple pie” filling (recipe here!), and I wanted an ambitious crust to make the pie really over-the-top. I’ve always loved apple crisps with pecan toppings, so I figured I could try out a pecan-based pie crust. But how best to incorporate pecans into notoriously fussy pie dough?

Basic pie dough: fat, flour, water

Mixing flour, butter, and a little shortening—but when, and how, to add pecans?

I don’t have much to add to the science of basic pie dough. I stand in the footsteps of giants—notably J. Kenji Lopez-Alt, who developed a newfangled way to reliably make great, flaky pie dough. His recipe eschews the traditional “cut cold butter into a mass of flour until pea-sized clumps form” method. Instead, you food-process the butter (and optional shortening) with some of the flour to make a fat-flour paste. Then you throw in the rest of the loose flour, add water, and squish to combine. Solid clumps of the fat-flour paste melt and spread out to form flaky layers. And the loose flour bonds with water to form just the right amount of gluten, the stretchy protein that gives baked goods structure (more about elasticity).

I love this recipe and I’ve used it many times. But I wasn’t sure how to incorporate pecans.

Pie #1

I didn’t want to just throw in loose ground pecans, because I figured they’d wreak havoc on the dough’s delicate texture. So for my first test, I substituted ground pecans for some of the flour in the fat-and-flour paste.

The result:

Pie #1. All butter, with pecans in the fat-flour paste—crumbly, not flaky.

Failure! The crust wasn’t nearly flaky enough. At its worst, the crust had the texture of a soggy pecan sandy. (On the plus side, I did determine that the pecans should be toasted.)

Pie #2

In the first pie, I used all butter, which melts easily. When the fat’s too soft, you get a homogeneous, crumbly texture instead of flaky layers.

So for my next pie, I tried the same method with a lot more shortening, which stays solid for longer than butter.

The result:

Pie #2. More shortening, less butter—still no flakiness!

Still no good. If anything this one was even more soggy and crumbly.

Maybe I was just overprocessing the dough, but I didn’t feel like making yet another pie with the same method just to make sure.

Pie #3

I decided to take a step back. What are pecans, anyway? As it turns out, pecans are almost 70% fat by weight. I had been treating the pecans as a substitute for flour. Maybe I should treat them as a substitute for fat?

In my next pie, I tried two very different approaches. For the top crust of the pie, I did what the facts about pecans seemed to suggest—I treated them as a substitute for fat and used less butter. I very finely ground the pecans with one tablespoon of shortening until a smooth paste formed, and I threw it in the freezer before proceeding, to ensure the pecans were as fat-like as possible.

For the bottom crust, I took the exact opposite tactic: I treated the pecans as a substitute for flour. And this time, I added them at the end, with the loose flour. So unlike all my other pies, the bottom crust’s pecans were not part of the fat-flour paste.

I did not expect the bottom crust to work. In fact, I assumed the bottom’s failure, and the top’s triumph, would prove my hypothesis: that pecans are basically fat and so should be treated like fat in a pie dough recipe.

Pie #3. Bottom crust, with pecans substituted for flour: flakiness achieved!

I was wrong! Look at those flakes on the crust rim. That’s part of the bottom crust, the supposed failure, but it came out perfect. Excellent flakiness, tender texture, and intense pecan flavor. The top crust had a somewhat flakier texture than my previous experiments, but it wasn’t as flaky as the bottom, and it tasted a lot worse—almost rancid.

To recap:


Pie (single crust)
 PecansFat / Flour ratioResult
Original recipeNone10 tbsp / 1 ¼ cupsFlaky
Pie #1Untoasted, processed with fat-flour paste10 tbsp / 1 cupCrumbly, needed toasting
Pie #2Processed with fat-flour paste10 tbsp (extra shortening) / 1 cupCrumbly
Pie #3, top crustGround with 1 tbsp shortening to paste, chilled, processed with fat-flour paste8 tbsp / 1 ¼ cupsSlightly less crumbly, weird taste
Pie #3, bottom crustPulsed in with loose flour10 tbsp / 1 cupFlaky

A tale of two fats

Why had my experiment shown the exact opposite result I was expecting? I believe it has to do with the difference between saturated and unsaturated fat.

Butter is largely saturated fat, which means it stays solid at room temperature. (Shortening is made from unsaturated vegetable oil, but it’s hydrogenated—basically an artificial saturation process, which makes it solid at room temp like butter). When those bits of cold, solid fat in pie dough melt in a hot oven, they spread out between sheets of gluten—that’s where flakiness comes from.

Pecans, on the other hand, are mostly unsaturated fat, which means the fat is liquid at room temperature. It can’t melt and spread out, because it’s already liquid. So even though pecans are indeed fatty, that fat just doesn’t behave much like butterfat or shortening, nor does it play well with those solid fats in the dough’s fat-flour paste. Hence, better to treat the pecans like loose flour, rather than trying to incorporate them into the fat-flour paste.

Why don’t those loose pecans mess up the dough’s texture? Because unlike flour, pecans don’t form gluten with water. Thus, they don’t affect the dough’s balance of gluten and fat—they just sort of sit there, in the background of the equation.

So there you have it. I may not have cured cancer or found the Higgs boson—I didn’t even manage to win the pie contest, alas—but I hope I’ve at least done my part to advance the science of adding nuts to pie dough without sacrificing flakiness. (recipe here!)

About Daniel Kenis

Daniel edits World Book's food and cooking articles, since they can be said to fall under the broad topic of technology. Among the encyclopedia articles in his charge are "Ice cream," "Internet," "Cooking," "Nuclear weapon," "Pie," and "Pi."

, , ,

6 Responses to Pie crust with pecans: a tough nut to crack

  1. Alexa November 2, 2011 at 7:10 pm #

    I now understand why your pie was so filling! And also so delicious. :) I love pecans.

  2. Karl November 7, 2011 at 11:34 am #

    So that’s how flakiness works…

  3. Eileen Enke January 21, 2012 at 6:54 pm #

    This is precisely what I’ve been questing for! Several years a local, upscale grocery chain with excellent bakery sold a caramel apple pie with a hybrid crust of flour and pecan meal.

    While I’m tempted to make yours as written, the DIL was promised a praline caramel apple pie (with the praline and caramel beneath the top crust.) Think I’ll use your crust and forego to the top crust this time Hmmm, if I want to get fancy perhaps making both recipes so there are two to compare………

    thanks,
    petite.cherie, the Mad Scientist in the Kitchen

  4. Angie M. January 30, 2012 at 8:50 pm #

    The link to your recipe didn’t work. Where can I find it? I think this pecan/flour crust will be fabulous with a sweet potato pie I’m going to make. Thanks!

    • Kevin Liu February 1, 2012 at 9:38 pm #

      Angie, thanks for pointing out the error. We just recently switched hosting and are still working out the kinks on this new site. The link should be fixed now, enjoy!

Trackbacks/Pingbacks

  1. Nuts for pie crust « Science Fare - November 30, 2011

    [...] my last post, I talked about a technique for adding pecans to pie dough for a maple-caramel-apple pie. Since I [...]