- Skills
- Cooking Methods
- Baking
Jill Waldbieser
Jill Waldbieser
published Dec 18, 2019
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I love pie — sweet pie, savory pie, hand pie, every pie. And I never questioned the way to finish a pie: Just before it goes in the oven, I brush it with a beaten egg white, because that’s how my grandmother had always done it.
But it turns out, when it comes to anointing your finished crust, there are as many options as there are pie fillings. The wide world of pastry washes includes not only a dizzying array of egg mixtures, but also oils, butter, milks, and even sugar water.
The purpose of all these coatings is to achieve a golden-brown bakery-case sheen. While the effect is mostly aesthetic, there are some practical reasons to wash pastry dough as well: It can help seal dough (in fact, brushing the inside of the crust is one of Kitchn’s tips for making apple pie bottoms less soggy) and it can help sugar or other toppings stay put.
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But pastry washes are not entirely interchangeable; different kinds produce different effects. In general, protein (such as eggs) and sugar (found naturally in milk) encourage browning, while fat (like oil) adds shine. Some of the best purported washes are mixtures, such as egg and milk or cream. Sugar-only washes, like maple syrup or honey thinned with water, can burn easily so I decided not to bother with those. But I wanted to give the others a whirl to see which were worthy and which were, well, a wash.
After some research, I selected six of the most popular. For dairy, I chose milk and almond milk (to see how a non-dairy milk would perform). For oil, I went with coconut oil. For egg washes, I chose two: an egg and water mixture that Kitchn recommends in our basic pie crust (recipe link below) and an egg and salt mixture recommended by Fine Cooking. Finally, I baked one no-wash crust, for both a point of comparison, and to determine whether a wash was truly necessary.
A Few Notes About Methodology
For testing purposes, I used Kitchn’s basic pie crust recipe. It’s easy and reliable — a basic flour, butter, and water mix. I made it as instructed, including chilling the dough twice: once before rolling and once after rolling. I brushed each wash on with a silicone baking brush, which worked fine, although some prefer a bristled pastry brush.Then each of these were rated based on color, sheen, and consistency of browning.
Not that it matters, but I also tested all of these washes on a traditional apple pie and a peach-maple-bourbon pie. Both were fantastic.
Method: Almond Milk
About this method: Nondairy milks have exploded into the market over the last few years, so vegans or those avoiding milk for any reason can take their pick of washes. With roughly half the fat of whole milk, and very few sugars, there’s not much there to provide color or sheen.
Results
I found that nut milk didn’t make for the most even wash; it was dark in several spots. Dairy-averse bakers may want to find a higher-fat milk alternative, and even add a little sugar to the mix before brushing it on to encourage browning.
Rating: 5/10
Method: No Wash
About this method: It’s rare to find a pastry recipe that doesn’t call for brushing your dough with something before popping it in the oven, but will dessert be ruined if you just skip it?
One test pastry went into the oven completely nude to find out.
Results
This pastry tasted fine (better than fine, actually), but there was a stark difference in its appearance — zero shine, and minimal browning. I might eat a pie without a pastry wash, but I might not serve one to guests: It would feel like something was missing. (But this is still preferable to the uneven browning from an almond milk wash.)
Rating: 6/10
Method: Coconut Oil
About this method: Another way to achieve a good sheen and browning is to simply use fat — in most cases, that would be an oil. Butter has a good deal of water in it, although some chefs recommend melted butter or even ghee (which is clarified butter, so the water is removed). I settled on coconut oil, as I thought it might work best with sweet pies.
Results
Beating an egg isn’t difficult, but I did appreciate the ease of being able to just brush a little oil directly onto the crust without having to break out a whisk. Ease aside, the crust browned ever so slightly, but it had no detectable shine. It’s not a bad option if you run out of eggs, are making a vegan dessert, or are just going for a more simple, rustic pie look.
Rating: 7/10
Method: Egg Beaten with 1/8 Teaspoon Kosher Salt
About this method: In an article on washes, Fine Cooking notes that some professional chefs add salt to their egg wash, as it helps break down the proteins and makes the egg easier to brush onto the dough. Unfortunately, it’s not instantaneous. The article recommends waiting “a minute or two,” but other sources have suggested waiting 30 minutes or even overnight, before brushing it on the crust. This makes some sense; J. Kenji Lopez-alt once tested the effect of salt on eggs at Serious Eats, and found at least 15 minutes were needed to make a difference.
Results
To be safe, I waited a full 30 minutes after salting before brushing the egg mixture onto my crust, to make sure the salt had the full effect. Additionally, I tried this method with a whole egg as well as just the white (it’s what Grandma would have done). In both cases, the shine was nearly perfect, but the gold color looked a bit too deep for me and a little uneven.
Rating: 7/10
Method: Whole Milk
About this method: Dairy is a classic pastry wash. The natural lactose sugars gild the crust with a golden hue, and the more fat the milk has the deeper the color you’ll get. What you won’t get is as high a shine as egg washes give you. As with oil, this wash is easy to apply, but also easy to over-apply. You want to avoid letting any liquid puddle on the crust, as it promotes uneven browning.
Results
The color of my crust was almost too yellow for my taste, and uneven, but I chalk that up to user error. I tried a second time with heavy cream, which was more viscous and easier to brush on evenly, which gave the pastry a more even color and a light sheen.
Rating: Whole milk: 7/10, Heavy cream: 8/10
Method: One Egg Yolk Beaten with One Tablespoon of Water
About this method: This is the most basic, go-to wash. You can vary it by using yolks only, whites only, or by altering the amount of water you add to vary the amount of shine. Yolks will give you a darker finish, whites a lighter one, and more water will dilute the wash and make it lighter still.
Results
This is a gold standard for a reason: It’s simple to make and it consistently looks great. The color isn’t too yellow or brown, and the shine is like a semigloss paint.
Rating: 9/10
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