Why Bubbles? Because Food's Negative Space Matters

Lightness. Levity. A little frivolity. These are the words we thought of when the idea of bubbles first came up in a brainstorming session for this digital issue many months ago. It felt right, especially as a follow-up to the moody visual tone of our first digital issue dedicated to the wok. 

Ha. What fools we were!

Bubbles may not weigh much, but there's nothing lightweight about them. It's probably not an exaggeration to say that scientists have a better understanding of how to land robots on Mars than they do of the physics of bubbles in our food. But we pushed ahead anyway to create this tribute to—if we may borrow an art-world term—food's negative space.

It's easy to look past the pockets of air that occupy so much of what we eat, but food as we know it wouldn't be recognizable without them. Bubbles inflate breads, lighten cakes and batters, aerate creams and mousses, and add fizz to so many drinks. They're a byproduct of fermentation, a critical determinant of texture, the thing that makes your eyes water as you let out an Aaahhhhhhhhhh after that first spicy sip of cold soda or beer. So much of what defines our food is all the stuff that's not there.

To organize the issue, we landed on the following (semi-unscientific) trifecta: Free, Foamy, Fixed.

"Free" bubbles would be the ones that move unrestricted through a liquid, most often in the form of carbonation or as a byproduct of fermentation. In this section, we go deep on kombucha, offer an easy recipe using pineapple scraps for Mexican tepache, check in on the beer industry's adaptation to a CO2 shortage, explore the science of boiling water, and find out how to listen to our morning coffee—because no, you're not dreaming, it really is talking to you (through bubbles!).

"Foamy" bubbles, meanwhile, gets us into the wild and wacky world of foams; to be clear, we do not mean that merely in the early 2000's molecular gastronomy sense. Foams are everywhere in the culinary world, from whipped creams to meringues (whether made from egg whites or aquafaba), doughs to batters, and the frothy heads of carbonated drinks and popular beverages like cheesefoam tea.

As for "Fixed" bubbles, well, this is where we're going to give every scientist reading this digital issue a headache, because technically what we're calling fixed bubbles are really still foams, just solid ones. A baguette or brioche dough doesn't stop being a foam just because it's been baked into bread, a genoise cake doesn't stop being one just because it's ceased to be batter, and flatulence-causing gas from beans doesn't stop being free just because it's trapped in a digestive tract.*

* Yes, there are farts in this issue: we teamed up with Dave Arnold (food scientist, founder of the Museum of Food and Drink, Radio Host, and much, much more) and some brilliant scientists at Harvard to run the first-ever study of common gas-reducing cooking techniques to see which actually work. All in the name of science, right?

The subject may have turned out to be weighty, but we never lost sight of keeping it light. Just like bubbles.