How one plant-based milk became our test kitchen's favorite "egg" wash

In the kitchen, new discoveries can occur when you least expect them. You might be elbow deep in baguette dough when you learn an eye-opening way to develop bread dough.  

Or, like King Arthur recipe tester Molly Marzalek-Kelly, you’re working on perfecting a batch of bagels when you discover your favorite new ingredient to make vegan egg wash.

What is egg wash, anyway? 

First, a quick baking refresher. An egg wash is typically made from whole eggs and water whisked together (in a ratio of 1 large egg to 1 tablespoon water), then brushed on the surface of a baked good before it goes into the oven. A whole egg is most frequently used, though sometimes you'll see it with just yolks for extra color or just whites for extra shine.

Photography and food styling by Liz Neily

Brushing the dough with egg helps with browning and developing a shiny, “glazed” crust. It’s most commonly used on pie crust, puff pastry, scones, rolls, and breads like brioche. Without it, baked goods may come out looking wan, with a dull, dried-out surface. An egg wash is also helpful for attaching toppings like seeds, acting like glue to keep them in place on the surface of the baked good.

Why soy milk is our new go-to vegan egg wash

“I was testing a new bagel recipe, and I wanted to see if there was a way to adhere Everything Bagel Topping that wasn’t just a regular egg wash,” says Molly. “I was looking for a vegan option since the rest of the recipe is vegan. Plus, I tend to be frugal about when I use a whole egg for just one batch of baked goods.”

John Sherman

While researching vegan egg washes, Molly developed a list of options to try that included melted coconut oil, a cornstarch-and-water slurry, and plant-based milk.

“I didn’t like the coconut oil,” she explains. “It had too much flavor, plus gave a slightly greasy feel to the bagel.”

As for the cornstarch slurry, “it left a light white film on the surface of the bagel” instead of a golden-brown sheen, according to Molly.

Which left the plant-based milk. Molly figured that the protein in soy milk would help with browning, so she gave it a try. (Why is protein important? The Maillard reaction that creates a browned crust in the oven occurs when both sugar and protein are present.) Sure enough, it resulted in nice color on her bagel tests, and it also made an excellent “glue” to keep Everything Bagel Topping and other toppings adhered to the surface of the bagel.

In what she calls “a happy testing accident,” Molly landed on her favorite new vegan egg wash.

How soy milk compares to other vegan egg washes 

Inspired by Molly’s insight, I decided to see how soy milk compares to some other common vegan egg washes, as well as the original standard: egg (plus a splash of water).

After doing some research on popular options, here’s what I landed on to test:

• Unsweetened soy milk  

• Unsweetened oat milk  

• Maple syrup  

• Maple syrup mixed with unsweetened soy milk  

• Vegan butter 

• Coconut oil  

• Aquafaba 

I baked a batch of Baking Powder Biscuits with each of these “egg” washes, plus a real egg wash to use as a control. I then evaluated the results based on shine, color, and overall performance.

Rossi Anastopoulo

After baking, I can totally see why Molly landed on soy milk. It gives baked goods both color and shine, while other options mostly only succeed with one or the other. Oat milk was also a good option, if that’s the plant-based milk you keep in your fridge. I imagine almond milk could serve in a pinch.

Vegan egg wash that brings both color and shine 

If you want to give your soy milk egg wash (or one made with another plant-based milk) a little extra boost, there’s one additional trick you can try: Stir in a little maple syrup (about 1 teaspoon per 2 tablespoons of soy milk should do the trick).

The sugar in the syrup provides even more browning on the surface of the baked good for a noticeable golden color. Unlike just maple syrup, the baked good still has some shine, which is why you want to use the combo with soy milk. Similarly, using a sweetened version of plant-based milk on its own would give you similar color, since there's more sugar present to promote browning.   

Overall, maple syrup + soy milk was the standout option of the bunch and the one I’d recommend for future baking — both vegan and non-vegan alike. And the best part? You can use only as much as you need, without the need to crack an entire egg just for one bake.  

If you’re looking to skip the eggs in all your baking, check out our collection of Vegan Dessert recipes.  

Cover photo by Jenn Bakos.