Sunday, July 29, 2012

Cracking the Coconut (Oil) for Pie Crust

The famous vodka-containing pie crust recipe from Cooks Illustrated has been my "go to" crust recipe for a few years (you can find it at Serious Eats). The free form galettes that use it have been crispy and flaky on many occasions, thanks in part to techniques and recipes I learned from books like Lindsey Shere's Chez Panisse Desserts and Rose Levy Beranbaum's Pie and Pastry Bible (see Building a Great Galette, Piece by Piece). But since I'm one-hundred percent against using the vegetable shortening specified in the recipe (because the hydrogenation process creates dastardly transfats), in my early attempts I substituted butter for the shortening. This substitution, however, is problematic because butter is not a pure fat like shortening – it's about 80% fat and 20% water, while shortening is 100% fat. An extra-careful baker might adjust the water and butter quantities to match the original quantities, but I had decent luck with the all-butter crust.

Shirley O. Corriher’s highly-regarded BakeWise notes that making a one-for-one swap of butter or margarine for shortening can lead to a less tender and/or less flakey crust. In addition, an all-butter crust is more difficult to roll out because a butter dough stays harder than a dough that contains shortening or lard. And so, if you try to get around this by letting the dough warm up a bit, the butter might dissolve into the flour matrix, thus reducing the potential number of layers that can be formed (and reducing flakiness).

Lard Lad
While entranced by the ideals of locavorism, I decided to try substituting lard for the vegetable shortening.  Lard is also 100% fat, so the substitution can be one-to-one without worries about dough damage.

Lard has had a bad name for quite a while (see, for example, NPR's Planet Money called "Who Killed Lard?”) but seems to making a comeback, mostly among those who are seeking out local meats, or those who want to follow old-style pie-baking techniques. Health-wise, it may not be as harmful as shortening and butter.  On the March 8, 2008 episode of KCRW's Good Food, Evan Kleiman talked with Local Forage co-editor Steven Fineberg about rendering animal fats at home and how to use them. He notes that pork fat has a relatively high fraction of monounsaturated fats, one of the fats that we sometimes think of as "good". His statement is confirmed up by a table in the latest edition of Harold McGee’s On Food and Cooking, which lists pork fat with 40% saturated, 45% monounsaturated and 11% polyunsaturated fatty acids (see p. 800 in the latest edition)*.

However, all lard is not the same.  Fineberg notes that the blocks of lard in the grocery store are often partially hydrogenated (i.e., full of transfats) and might also have fillers, so it’s best to make your own or find a good source. I buy leaf lard (the most prized lard for pie making) from Prather Ranch, which has a stand in the San Francisco Ferry Building and sells at farmers markets in the Bay Area. I think I have also seen leaf lard at the Marin Sun Farms shop in Market Hall in Oakland.

Substituting lard for shortening in the pie crust worked well, but was bad news for vegetarians and those who avoid pork.  With this weighing on my conscience, I tried another fat substitution: replacing the shortening with coconut oil**.
 
Cracking the Coconut Oil

For a long time, coconut oil was regarded by Western nutritionists as something to be avoided at all costs – “the devil himself in liquid form, with more poisonous artery-clogging, cholesterol-raising, heart-attack-causing saturated fat than butter, lard or beef tallow,“ wrote Melissa Clark in the New York Times.  These days, though, nutritionists think it’s not so bad in moderate quantities (i.e., think of it like any other saturated fat). Part of coconut oil's demonization, Clark writes, is a result of early studies that used partially-hydrogenated coconut oil, an oil that was chock full of transfats. Today it's pretty easy today to find pure, unprocessed coconut oil at the health food store (and even possible to buy fair trade coconut oil from companies like Dr. Bronner’s).

My first attempts, in which I didn't really pay attention to fat temperature or do anything special, the results were superb. The crust was as crispy, tender and flaky as before, but now with the subtle flavor of coconut. But then my luck ran out: on one tart, the coconut oil separated from the crust in the first few minutes of baking, leading to a pool of oil in the pan and a lousy crust.

Determined to avoid this, I carefully experimented for a few months, trying various approaches to handling the coconut oil.

Hard Lessons
If you've worked with coconut oil, you know that it is quite different than shortening, butter or lard. Straight out of the refrigerator, it can be so hard that you need a sharp knife to break off pieces – and great concentration to avoid injuring yourself ***.  If the pieces are too big in the dough, you'll end up with bits that the rolling pin bumps over, preventing the crust from being the desired thickness and leading to holes in the dough. To deal with this hard problem, I ended up slicing the coconut oil into thin slices before adding it to the food processor, thus preventing large rolling-pin disturbing bumps.

I (Don't) Melt With You
The problem of escaping coconut oil mentioned earlier had a relatively simple solution: chilling the galette before baking. To understand why this helped, let's take a detour into food science.

Ideally, an unbaked pie crust will be a series of alternating layers of fat and dough. When baked, the starch in the dough gelatinizes to create a solid structure with the fat trapped between the layers. Also during baking, some of the water in the dough evaporates, creating puffiness and lightness. Consequently, it is critical that the fat in a pie dough remains solid until the dough on each side of each fat pocket can set. Shortening and lard stay solid nicely during the setting process, but butter needs to be quite cold when the dough goes into the oven or it will melt away before the layers are set (this information is from Corriher’s BakeWise). It turns out that coconut oil is similar to butter, requiring the finished galette to spend 15 or so minutes in the refrigerator before going into the oven.

A forthcoming post will have the recipe I’ve been using in an easy to use format, along with some notes related to the use of coconut oil.

Notes
* For reference, coconut oil is 86% saturated / 6% monounsaturated / 2% polyunsaturated and olive oil is 13% / 74% / 8%.
** I have coconut oil on hand for pie crust and one other recipe: Heidi Swanson's granola bars in Super Natural Cooking (see my review of the book at the Ethicurean). An adaptation of the recipe by Sam Breach at Becks and Posh is here.
*** Strangely enough, coconut oil might have a lower melting point than butter. Vaughn’s Summaries, which is a compendium of information from many sources, states that the melting point of coconut oil is 75 F (24 C) while butter fat melts at 95 F (35 C).  Melting point, however, is not the same thing as hardness (I’m not sure how food scientists define the hardness of a solid fat.  Is there a Mohs scale for fats?)


 Random link from the archive:  Symphonic Cookies

2 comments:

Jirka said...

Your pie looks awesome. Just like your blog with great recipes.

MaryLu said...

Some friends and I are having a pie baking class and we have been discussing the use of cocnut oil instead of shortening. Your post was extremely helpful and we will be reading and using your blog as a reference. Thank you very much.