It was the best of pies, it was the worst of pies. I have baked many, many, many pies.
And when I first began making pumpkin pies this autumn, my results were at best inconsistent and, at worst, disastrous.
"One of the problems is most people make it once, maybe twice a year, right around the holidays, so they're not very practiced at it," says Dan Souza at America's Test Kitchen. "And pumpkin pie is a little bit different in that it's essentially a custard baked into a pie shell." In trying to juggle both components, even experienced bakers may end up with a grainy, overcooked filling or a soggy crust, Souza says. "There's a lot of places you can slip up."
So Souza and J. Kenji Lopez-Alt, a chef and author of The Food Lab: Better Home Cooking Through Science, coached me through the process.
The Ultimate Custard
"Mainly it's the texture that can go very wrong," Lopez-Alt says. "It can end up grainy, or kind of broken up like scrambled eggs."
See, a classic pumpkin pie filling includes a few eggs, as well as pumpkin puree, some cream, sugar and spice.
"As the custard cooks, there's a loose network of the egg proteins that intertwine with each other and set to give the filling structure," Lopez-Alt explains. Ideally, you want to cook the custard just enough to form a soft, gel-like texture. "But as the custard keeps cooking, the eggs start to set so tightly that they squeeze moisture out," he says. That's when you get an icky, lumpy pie.
Both Lopez-Alt and Souza recommend cooking the filling quickly, but gently: The center of the pie should never get any hotter than about 175 degrees Fahrenheit.
And you've got to try to cook the pie as evenly as possible. Some cracking at the center of the pie is inevitable, Lopez-Alt says. It happens because the edges of the pie tend to cook and set faster, and pull at the center, which takes longer to cook.
Souza's pro tip is to bake the pie at about 400 degrees Fahrenheit for about 10 minutes, until the filling just starts to set, and then lower the oven temperature to about 300 degrees until it cooks through. "By lowering the overall temperature, you get less of a disparity between temperature at the perimeter of the pie, and the temperature at the center," he says. He also recommends heating the filling on the stove for a bit, so it has to spend even less time cooking unevenly inside the oven.
Oh, and padding the custard with lots of fat helps as well. Souza's recipe calls for three eggs plus two egg yolks. "By ditching some of the egg whites, you're reducing some of the water content, so the filling takes less time to firm up," he explains. "And the fat in the egg yolks also serves as a buffer to keep the proteins from over cooking."
Lopez-Alt suggests substituting the cream in the filling with cream cheese for a similar reason: It helps the custard cook more evenly for a smooth, creamy end result.
The Ideal Crust
Over the past few months, I tried nearly everything to avoid ending up with soggy, mushy pie crusts. I pre-baked and crisped up my crusts before pouring in the filling. I tried brushing the bottom of my crust with some egg wash — to waterproof it. I pleaded with the culinary gods and complained to my friends and cried to my mother.
All of this, to no avail.
And then Lopez-Alt suggested something wacky and wonderful: vodka. Not to drink (though a shot or two have served to console me after a culinary disaster). Lopez-Alt suggests substituting some of the water used to pull the pie dough together with a tablespoon or two of vodka. "When you mix flour with water, it produces gluten," he explains. "And gluten is what makes your pie dough tough rather than flaky."
But gluten doesn't form in the presence of alcohol. "Plus the vodka evaporates a bit more quickly when you bake the crust, so you're less likely to end up with a soggy crust," Lopez-Alt says.
He also suggests blending flour and butter together in the food processor. "That way you need to add barely any water at the end to bring the dough together," he says. "But the dough is still very soft, and easy to roll out."
Pre-bake the crust until it's golden brown, and then, Souza says, fill it with a custard that you've already heated and thickened up a bit on the stove. "That way," he says, "the filling is less likely to seep and soak through the crust, and ruin that buttery, flaky goodness."
The Richest Flavors
Canned or fresh squash?
The experts agree it doesn't really matter.
If you are using the fresh stuff, Lopez-Alt recommends roasting it very slowly in the oven — at around 275 degrees Fahrenheit. "Pumpkins and squashes have these enzymes that will break down some of their starches and convert them to sugar," he says. "Cooking them slowly can actually accelerate that process." Slow-roasting also allows for more water to evaporate from the squash, concentrating its flavor.
And feel free to experiment with different squashes. Sugar pie pumpkins are classic, but butternut and kabocha squash can often taste sweeter and more "pumpkin-y" than the traditional orange gourds. "Just never use one of those Jack-O-Lantern pumpkins," Lopez-Alt warns. "Those are meant to look pretty, but they taste nasty."
But Souza says people can rarely taste the difference: "I think you may as well save yourself the effort and use a can."
Of course, a judicious sprinkle of spices, some maple syrup and even a bit of sweet potato can deepen and enhance the flavor.
The Taste Tests
My journey to learn the art and science of the ideal pie has been long. Very, very long. I've baked a total of 10 pies over the past three months. I wanted to perfect my pie by Thanksgiving — but that didn't happen. Instead, I berated my Thanksgiving guests: "You're saying it's good, but what does that even mean? Be more constructive with your criticism!"
I faced many setbacks: I badly burned a couple of crusts. And, despite all the coaching, I curdled some custard. Take note, folks: Timers and thermometers are key.
But finally, in mid-December, I brought in two pies that combined all that I had learned to face my toughest critics yet: NPR's Science Desk.
For one pie, I used freshly roasted squash and cream cheese. I made the other with canned pumpkin. One of the crusts had some shortening, whereas the other was pure butter. And I used a good shot of vodka in both, of course.
Each pie had its fans.
My editor, Maria Godoy*, liked the cream cheese. "It's like creamy pumpkin... Like, if pumpkin were milk."
NPR Skunk Bear's Adam Cole disagreed: "Not my cup of tea." He liked the canned pumpkin better. [*Editor's note: Adam has an admitted preference for bland food.]
Photo editor Ryan Kellman said he was divided, insisting "I need to probably to eat a lot more of this" in order to decide.
And science correspondent Geoff Brumfield was no help at all: "I mean, I'm just here to eat some pie."
I'm still not satisfied. A bit more ginger may have given the pies more kick. The cream cheese filling didn't taste pumpkin-y enough, and the other one tasted perhaps too pumpkin-y. Maybe I should have baked the crusts a bit longer. Maybe I should have cooked the custard a bit less.
True perfection — and success — remain just beyond reach. Guess I'll have to pie, pie again.
MICHEL MARTIN, HOST:
And the holidays are a time for pie - lots and lots of pie - sweet potato, cherry, pecan and, of course, pumpkin. If you have attempted this yourself, then you know making a good pumpkin pie is no small endeavor. You could end up with a soggy crust or egg-y filling. And that is why NPR's Maanvi Singh went on a journey to learn the art and the science of the ideal pie.
MAANVI SINGH, BYLINE: I wanted the best of pies, more often I got the worst of pies. I made many, many, many pies and my results were, at best, inconsistent. So I went to the experts - the ones who really knew the science and the secrets to making the perfect pumpkin pie. First, I called up Dan Souza at ""America's Test Kitchen."
DAN SOUZA: I mean, one of the problems is most people only make it once, maybe twice a year, right around the holidays, so they're not very practiced at it.
SINGH: And there's a lot to think about - fresh or canned pumpkin, which crust recipe.
SOUZA: There's a lot of places where you can slip up.
SINGH: He started by coaching me through the filling. Souza says it's not so much about the ingredients but how you cook them.
SOUZA: The - a custard - baking is really all about hitting that ideal temperature. And we don't really want to go over 175 degrees.
SINGH: If the custard gets any hotter in the center, the eggs will begin to overcook and curdle - blergh. I learned another trick from Kenji Lopez-Alt. He's a chef and author of a book called "The Food Lab: Better Home Cooking Through Science." His secret is cream cheese.
LOPEZ-ALT: Some of the stabilizers and emulsifiers in the cream cheese will actually help keep that pumpkin pie filling nice and smooth.
SINGH: Brilliant. As for the crust, Lopez likes butter over shortening or lard for flavor, but...
LOPEZ-ALT: The problem with using butter, though, is that it has some water content in it, which means that when you add it to your flour, you develop gluten. And gluten is what makes your pie crust tough.
SINGH: You also want to minimize the water you add to pull the dough together. It helps to blend the flour and butter in a food processor. That makes for a softer dough that requires less water. Plus, something I never would've guessed - use vodka instead of water - gluten doesn't form in the presence of alcohol. The booze is also handy to have around for consolation when you mess up, which I did many times before getting it right.
Two tablespoons of sugar.
I invited my friends, Meredith and Lexi (ph), to bake with me.
SINGH: Wait, why won't this food processor work?
It was a fraught experience at times.
Guys, I think I failed already.
So I badly burned a couple of crusts, and despite all the coaching, I curdled some custard. Take note, folks, timers and thermometers are key. But finally, I baked two pies that combined everything I had learned. And I faced my toughest critics yet at NPR's science desk. For one pie, I used freshly-roasted squash and cream cheese. I made the other with canned pumpkin. One of the crusts had some shortening, whereas the other was pure butter. And I used a good shot of vodka in both, of course. Each iteration had its fans.
ALLISON AUBREY, BYLINE: It's like creamy pumpkin - almost like if pumpkin were milk.
UNIDENTIFIED WOMAN #2: Anyway, I think this one's really, really good...
GEOFF BRUMFIEL, BYLINE: OK, Allison, you have - you have to stop eating that pie because we have to eat the other pie.
UNIDENTIFIED WOMAN #2: Well, this one tastes completely different.
BRUMFIEL: I need, probably, to eat a lot more of this.
SINGH: OK, but maybe a bit more ginger would've done good. Maybe I should've baked the crust a bit longer. Maybe I should've cooked the custard a bit less. I still don't feel like I've succeeded - guess I'll just have to pie, pie again.
Maanvi Singh, NPR News. Transcript provided by NPR, Copyright NPR.