Black Hole Star Cake

  • By Greg Kestin
  • Posted 01.11.18
  • NOVA

NOVA has teamed up with Cook's Illustrated to cook up a recipe for stars and black holes—a culinary course on how the most mysterious objects in the universe are created. Find out more in this episode of What the Physics?!

Running Time: 05:10


Black Hole Star Cake

Published January 10, 2018

GREG KESTIN: The physics of black holes and stars is tough to digest.

So, I'm here with the senior editor at Cook's Illustrated Lan Lam, and she has made something incredible.

LAN LAM: I developed a recipe for a cake that goes through the life cycle of a star. This cake is going to change colors and then collapse into this smoking black carcass of a former star.

KESTIN: You're gonna learn about stars, black holes, and cooking all at once.

KESTIN: What ingredients do we have here?

LAM: So, in any cake one of the key ingredients is sugar. I also have some cake flour. Next up, one of the key ingredients to this cake in particular. It's fumaric acid.

To round out our dry ingredients I have some baking powder for lift. And we're gonna season our cake with a little bit of salt.

KESTIN: A key ingredient to any star, including the huge ones that will become black holes, is hydrogen there's also some helium, and a little bit of carbon dioxide, dust, and water. They all get mixed together in a diffuse nebula, a stellar nursery

To make a cake you also need some water.

LAM: We're going to mix this water into the dry ingredients to make a batter and mixing disperses all of the ingredients evenly, it breaks up the clumps, and all of that ensures a nice rise and expansion in the microwave.

KESTIN: The stellar nursery gets mixed up and spun from its magnetic interactions with the galaxy at large. This spin is going to make the star it creates spin, but before that happens, we need to put in two special ingredients: gravity and time.

LAM: Our cake also has two special Ingredients. I have here butterfly pea flower powder.

KESTIN: Okay, that a mouthful.

LAM: I had to practice it a couple times.

I'm going to sprinkle this into our egg whites, and I'm doing that because alkaline egg whites will help enhance its blue color

Now we just have to wait for three minutes.

KESTIN: Now we just have to wait for a million years. And the nebula starts forming a blue giant star.

LAM: This cake gets its lift from the air that's beaten into these egg whites.

When I beat the egg whites their proteins will start to unwind and then they tangle with each other, and in doing so they trap air to form a foam. I'm gonna stabilize that foam by adding a little bit of sugar.

KESTIN: Okay, so now we have the foam and the batter…

LAM: Yes let's bring it all together. I'm just gonna add about a third of this foam. Let's get the rest of this in. I've got some greased bowls here. I'm just going to fill them and then give them a quick mist of water, and let's head to the microwave.

KESTIN: All right. I'm so excited to see what this thing's gonna do.

As the star burns, hydrogen at the star's core fuses into helium, the core heats up and pushes the outer layers of the star further outward, and the star grows.

Something's definitely going on. It's getting pretty huge.

LAM: So, it might look like it's going to overflow but it won't. What's happening is all that air that we trapped in the egg foam is expanding due to the carbon dioxide produced by the baking powder.

KESTIN: While the core's getting hotter, the outer layers of the star are actually cooling down due to the expansion. And like a flame, as it gets cooler, the star goes from blue to red.

It's starting to get like purple, it's starting to get a little red.

LAM: The fumaric acid is causing the batter's pH to drop and as that pH gets lower and lower the butterfly pea powder goes from blue to red.

KESTIN: The nuclei at the star's core fuse into heavier and heavier elements, eventually reaching iron, which can fuse no more. With no more outward gas pressure from fusion, gravity overwhelms the central structure of the star, which implodes, while expelling the out layers of the star in a supernova. The core then collapses into a black hole.

LAM: And you can see all the black smoke that it's emitting right now.

KESTIN: Yeah, it's definitely smoking and turning black.

These look pretty cooked.

Should I try it?

LAM: Absolutely.


LAM: I would describe it as charred sugar.

KESTIN: Charred sugar black hole.

That is what I would think a black hole would taste like.

LAM: Want to try these?

KESTIN: All right. Cheers.

LAM: Cheers.

KESTIN: Thanks for watching.

It's crunchy and chewy. It's sweet, but a little sour. Candy, but cakey. It's like everything in the universe.

LAM: If you are interested in the recipe development process or wanted to get a look at the recipe, click the Cook's Illustrated link below.

KESTIN: Subscribe, like, all that good stuff. Thanks for watching.


Writer, Host, Producer: Greg Kestin

Cinematography: Brian Kantor and Ari Daniel

Editorial Input form: Julia Cort

Editor in Chief, Cook's Illustrated: Dan Souza

Senior Editor, Cook's Illustrated: Lan Lam

Scientific Consultants: Scott Kenyon

Animation: Edgeworx

Editing and Animation: Greg Kestin

Special thanks: Entire NOVA and Cook's Illustrated teams

From the producers of PBS NOVA © WGBH Educational Foundation

Funding provided by FQXi

Music provided by APM

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