When you boil baking soda in water, it transforms into a different compound: washing soda (sodium carbonate). The reaction releases carbon dioxide gas (those bubbles you see) and water vapor, leaving behind a solution that’s noticeably more alkaline than what you started with. This simple chemical change is the reason boiling baking soda makes it a stronger cleaner, and it’s useful for everything from rescuing burnt pans to deep-cleaning laundry.
The Chemistry Behind the Change
Baking soda (sodium bicarbonate) is not particularly stable when heated. It actually starts breaking down at temperatures as low as 122°F (50°C), and by the time water reaches a full boil at 212°F (100°C), the conversion to sodium carbonate is essentially complete. The reaction splits each molecule of baking soda into three products: sodium carbonate, water, and carbon dioxide. That carbon dioxide is the fizzing and bubbling you’ll notice in the pot.
In practical terms, you don’t need to boil for long. Once the water is at a rolling boil, the decomposition happens rapidly. Five minutes of active boiling is more than enough to convert the baking soda in a typical pot of water. If you’re just dissolving baking soda in hot tap water without boiling, the conversion will be partial, and you’ll end up with a mix of both compounds.
Why the Solution Gets More Alkaline
This matters because sodium carbonate is a significantly stronger base than sodium bicarbonate. At the same concentration, a baking soda solution has a pH of about 8.3, which is mildly alkaline. Sodium carbonate solution jumps to roughly 10.5, making it about 100 times more alkaline on the pH scale. That shift is what gives boiled baking soda its extra cleaning muscle. The higher pH is better at breaking down grease, dissolving proteins, and loosening baked-on grime.
You can actually buy sodium carbonate directly (it’s sold as “washing soda” in the laundry aisle), but boiling regular baking soda achieves the same result with something most people already have in the kitchen.
Cleaning Burnt Pots and Pans
This is probably the most common reason people boil baking soda. If you’ve scorched food onto the bottom of a pan, adding a few tablespoons of baking soda to water and bringing it to a boil in that pan works remarkably well. The alkaline solution attacks the carbonized food from a chemical angle, breaking down the bonds holding the char to the metal surface. Meanwhile, the rolling boil provides physical agitation that loosens debris further.
For a lightly burnt pan, 10 to 15 minutes of simmering is usually enough. For serious scorching, let the solution cool in the pan and soak for a few hours before scrubbing. The mild abrasiveness of any undissolved baking soda particles helps with the final scrub. This works on stainless steel, enamel, and most cookware, though you should avoid it on aluminum, since the high alkalinity can discolor the surface.
Laundry Stripping
Boiled or very hot baking soda is also a key ingredient in “laundry stripping,” a deep-cleaning method for towels, sheets, and workout clothes that have built up residue over time. The process involves filling a bathtub with very hot water and adding about a quarter cup of baking soda (or washing soda) along with borax and powdered detergent. You submerge the already-clean laundry, stir every so often, and soak for three to six hours.
The hot water converts some of the baking soda to the more alkaline sodium carbonate, which helps dissolve mineral deposits, body oils, and detergent buildup trapped in the fabric fibers. If you’ve ever done this with white towels, you’ve likely been startled by how brown the water turns. After soaking, you run the items through a water-only wash cycle to rinse everything out. Using washing soda directly (or pre-boiling the baking soda) is more effective than adding plain baking soda to warm water, since you get the full alkaline strength from the start.
Drain Clearing
A popular home remedy for slow drains involves pouring baking soda into the drain, following it with vinegar, and then flushing with boiling water. The fizzing reaction between baking soda and vinegar produces carbon dioxide gas, and in the enclosed space of a pipe, that gas pressure can help nudge soft blockages. The boiling water then melts and flushes away grease that’s solidified inside the pipe.
It’s worth being realistic about this method. It works for minor buildup and slow-running drains, but it won’t clear a serious clog the way a mechanical snake or enzyme cleaner would. The chemical reaction between baking soda and vinegar actually neutralizes both ingredients, producing mostly salt water and carbon dioxide. So the fizzing looks dramatic, but the end result is a fairly mild solution. The boiling water itself is doing most of the heavy lifting on grease.
Handling the Stronger Solution Safely
Because boiling converts baking soda into a much more alkaline substance, the resulting solution is harsher on skin than plain baking soda dissolved in cool water. Sodium carbonate can irritate skin on prolonged contact and is more serious if it gets in your eyes. When you’re working with a pot of boiled baking soda solution for cleaning, use rubber gloves and avoid splashing. If it does contact your eyes, rinse thoroughly with water for several minutes.
For most household cleaning tasks, the concentrations involved (a few tablespoons in a pot of water) aren’t dangerous, but they can dry out and irritate skin if you’re scrubbing barehanded for an extended time. The solution is also slippery, which is actually a sign of its alkalinity, since strong bases have that characteristic soapy feel.
Cooking and Baking Implications
This same decomposition is what makes baking soda work as a leavening agent. When you put baking soda in cookie dough or pancake batter and expose it to oven heat, it breaks down and releases carbon dioxide gas, creating the air pockets that make baked goods rise. In recipes that also include an acid (buttermilk, lemon juice, yogurt), the reaction starts before heating and produces even more gas.
Some recipes deliberately call for boiling baking soda in water before adding it to a batter or dough. This is common in certain pretzel recipes and traditional biscuit methods, where the more alkaline sodium carbonate solution promotes browning through a reaction between sugars and proteins on the surface. It’s the same principle behind the deep golden crust on a traditional Bavarian pretzel, which is dipped in an alkaline solution before baking. Using boiled baking soda gives you a milder version of that effect without handling lye.