The Delicious Thing That Happens When You Add Baking Soda To Toffee

If you have ever made toffee at home, or at least hovered nearby while someone else bravely tackled molten sugar, you have likely seen that mysterious step at the end: right as everything hits a deep amber, the recipe suddenly demands a splash of baking soda. Not salt. Not vanilla. But Baking soda! Why? Here's the short answer: chemistry. Here's the longer, more delicious answer: baking soda makes your toffee crunchier, airier, and just better.

There is a lot of science behind how baking soda works in such recipes. When you stir it into your hot toffee mixture, baking soda reacts with the acidic sugars and butter in the pan, creating a fizzy burst of carbon dioxide gas. That might sound like something you would want to avoid in a candy that's supposed to harden into shiny, glassy sheets, but those bubbles are exactly the point. They create tiny pockets of air throughout the toffee, giving it that light, crisp snap when you break it apart (instead of the jawbreaker density you might get otherwise).

Think of it like the candy version of aerating your cake batter. The process is a lot like what happens when making honeycomb candy (aka sponge toffee), where baking soda is the star player. In honeycomb, the bubbles are exaggerated for drama and chew; in English toffee, they are more subtle, like background singers making the lead taste shine.

From cleaning your kitchen to softening your canned chickpeas, baking soda does everything, and we cannot undersell the transformation it brings to your toffee either. Without baking soda, your toffee might still taste fine, but it will be much denser — sometimes aggressively so. That can mean unpleasantly chewy centers or edges that feel more like weaponized caramel than dessert. You will even notice the difference when breaking it up for serving; the pieces come apart in satisfying, glassy cracks, not frustrating lumps. Also, a pro tip: Add the baking soda only after removing the toffee from heat. Stir it in quickly and watch it puff up slightly, changing texture right before your eyes. (It's a good time to pour it immediately into your prepared pan — hesitate too long and you'll have a volcanic candy situation on your hands.)

Baking soda also plays well with add-ins. Want to swirl in some chopped almonds or drizzle with chocolate? Go for it. The airy base will hold them beautifully without turning rock solid. And if you are the kind of person who likes mixing broken toffee bits into cookies, brownies, or even over ice cream, the soda-enhanced texture makes for better crumbles and crunches every time.

So the next time a toffee recipe calls for baking soda, don't question it. Don't skip it. That unassuming little scoop is the unsung hero of candy-making, turning your sugar-butter masterpiece from solid snack to snap-happy showstopper. Science never tasted so good!