How to Make Washing Soda from Baking Soda
Learn how to make washing soda at home using baking soda and your oven. A simple, money-saving method for natural cleaning that really works.
It never fails. You’re all geared up to make your monthly batch of homemade cleaners, and—bam—you’re out of washing soda. That’s exactly what happened to me. I figured a quick trip to Wal-Mart would fix it, but their shelves were empty. Again the next week. And then a store clerk told me they wouldn’t be carrying it anymore—but “they have plenty of baking soda.” As if that’s the same thing.
Spoiler alert: it’s not.
After checking every store in the county, I was just about ready to give up. Then someone at the tiny local hardware store mentioned that her nephew had made some for a school project. “It’s just heated-up baking soda,” she said. I was skeptical. But I tried it anyway.
And guess what? It worked.
What’s the Difference Between Baking Soda and Washing Soda?
This part matters. Baking soda and washing soda aren’t interchangeable, but they’re closely related.
Baking soda (sodium bicarbonate) becomes washing soda (sodium carbonate) when it’s heated to the right temperature. That heat drives off carbon dioxide and water, leaving behind a more alkaline, more powerful cleaning agent. It’s not just fluff—it’s chemistry.
Baking soda has a pH of around 8 and is great for gentle deodorizing.
Washing soda has a pH of 11 and is strong enough to cut grease, lift stains, and soften hard water.
How to Make Washing Soda at Home
If you’ve got baking soda and an oven, you’re halfway there. This process is simple, fast, and saves you a trip to the store.
Step-by-Step Instructions
1. Preheat your oven to 400°F.
You need consistent, dry heat to trigger the chemical reaction.
2. Spread baking soda in a thin layer on a baking sheet.
Use a rimmed metal sheet or a glass baking dish—no more than ¼” thick. Thick layers may not convert fully.
3. Bake for 1 hour, stirring occasionally.
Use a wooden spoon—rubber will melt (ask me how I know). Stirring ensures even heating.
4. Check for changes.
Washing soda looks dull and grainy, unlike baking soda’s soft, fluffy texture. If you’re unsure, compare it side-by-side with unbaked soda.
5. Let it cool completely before storing.
Washing soda is hygroscopic (it absorbs moisture from the air), so store it in an airtight container in a cool, dry place.
Safety Notes
Keep it labeled. Store homemade washing soda away from food items and clearly mark it to avoid mix-ups.
Don’t inhale the dust. Washing soda is more caustic than baking soda and can irritate your lungs and skin.
Avoid aluminum pans. Sodium carbonate can react with aluminum, so stick with stainless steel or glass.
How to Tell If It Worked
Still not sure if you got it right?
- Visual test: Washing soda is gritty, not powdery.
- Feel test: It should feel dry and a bit like fine sand.
- pH test: If you’re curious, dissolve some in water and test with a pH strip. Washing soda will read around pH 11. Baking soda will read closer to 8.
Why Make Washing Soda Yourself?
Availability: In some areas, washing soda just isn’t sold locally anymore. This method keeps you from having to rely on online orders or big box stores.
Cost: Baking soda is cheaper and easier to find. Making your own washing soda saves money—especially if you use it often.
Self-Sufficiency: There’s something satisfying about being able to make your own basic supplies. It’s one more way to simplify, cut plastic waste, and take control of your home environment.
Storage Tips & Shelf Life
- Let your washing soda cool completely before storing.
- Keep it in an airtight container in a cool, dry place like a pantry or cupboard.
- Label it clearly, and avoid storing it near food.
Shelf life: Indefinite, as long as it stays dry. If it gets clumpy or looks “off,” it may have absorbed moisture and reverted to baking soda.
What Is Washing Soda Used For?
Also known as soda ash or sodium carbonate, washing soda is a natural, heavy-duty cleaner. It’s best known for laundry use but has lots of other applications:
- Laundry detergent booster: Try it in my homemade laundry soap recipe.
- Dish soap base: I love this liquid dish soap from The Prairie Homestead for quick hand washing.
- Fabric prep: Root Simple explains how to use washing soda to prep cotton for dyeing.
- All-purpose cleaner: One Good Thing by Jillee shares 39 creative uses, from de-greasing pans to cleaning patio furniture.
Frequently Asked Questions About Making Washing Soda
Before you jump in, here are a few things people often ask:
Want to remember this later? Pin this post to your Natural Cleaning board so you’ll never be stuck without washing soda again.
Making your own washing soda is quick, easy, and surprisingly satisfying. It’s a great way to make your home cleaning routine a little more self-sufficient and a lot more eco-friendly. Whether you’re whipping up laundry soap or prepping fabric for a dye project, this pantry-to-cleaner swap just makes sense.
Have you tried making your own washing soda? Drop your tips or questions in the comments—I’d love to hear how it went!