Sodium carbonate is a versatile alkaline compound used across dozens of industries, from laundry detergent to glass manufacturing to food production. You probably know it better as “washing soda” or “soda ash.” Global production hit an estimated 73 million metric tons in 2024, making it one of the most widely produced chemicals on the planet.
Cleaning and Water Softening
The most familiar use of sodium carbonate is in household and industrial cleaning. It shows up in laundry detergents, automatic dishwasher soaps, and all-purpose cleaners. Its cleaning power comes from two properties: it’s strongly alkaline, which helps break down grease and organic stains, and it softens hard water by binding to the calcium and magnesium minerals that interfere with soap performance. When those minerals are neutralized, detergents lather better and leave fewer residues on clothes, dishes, and surfaces.
Sold on its own as “washing soda,” sodium carbonate is a popular standalone cleaner for tough jobs like degreasing ovens, scrubbing tile grout, and stripping buildup from laundry machines. A small amount dissolved in water creates a strongly alkaline solution that cuts through grime more aggressively than baking soda, its milder cousin.
Glass and Industrial Manufacturing
By volume, the single largest use of sodium carbonate is in glass production. It acts as a flux, lowering the melting point of silica sand so manufacturers can form glass at achievable temperatures. Without it, producing flat glass, bottles, and fiberglass would require far more energy. China alone produced an estimated 36 million tons of soda ash in 2024, most of it feeding that country’s massive glass and chemical industries. The United States and Turkey round out the top three producers globally.
Beyond glass, sodium carbonate is a key ingredient in making other chemicals, paper pulp, soap, and certain dyes. It’s also used in metallurgy to refine ores and in the production of sodium-based compounds like sodium silicate (waterglass), which itself has applications in adhesives and sealants.
Food Production
In the food industry, sodium carbonate functions as an acidity regulator, raising the pH of foods to achieve specific textures and flavors. Its most celebrated culinary role is in Asian-style alkaline noodles, including ramen. Adding it to noodle dough creates the springy, chewy texture and yellow color that distinguish ramen from ordinary wheat noodles. It’s approved for use in dried noodles and certain specialty pastas under international food standards.
You’ll also find it used as a leavening agent in some baked goods, where it reacts with acidic ingredients to produce carbon dioxide gas that makes dough rise. In European food labeling, it appears as additive E500. Other food applications include pretzel-making (where it creates that distinctive dark, glossy crust) and processing cocoa powder to mellow bitterness, a technique known as Dutch processing.
Water Treatment
Municipal water systems and swimming pool operators use sodium carbonate to raise the pH of acidic water. Because it’s food-grade safe and dissolves easily, it’s a straightforward way to bring water closer to a neutral pH of 7. Acidic water corrodes pipes and leaches metals, so adjusting pH with sodium carbonate protects both infrastructure and drinking water quality. It’s considered completely safe for this purpose when food-grade material is used.
Personal Care Products
Sodium carbonate appears in some toothpastes as a mild abrasive that helps scrub surface stains from teeth. It’s also added to certain bath products, including bubble baths and bath salts, where it softens the water and creates a silkier feel. In these formulations it typically plays a supporting role, present in small concentrations alongside other ingredients.
Where Sodium Carbonate Comes From
There are two routes to producing soda ash: mining it from natural deposits or synthesizing it chemically. In the United States, all production comes from natural sources. Companies in Wyoming and California extract it from trona ore (a mineral that’s roughly half sodium carbonate) or from sodium carbonate-rich underground brines. Wyoming’s Green River Basin holds the world’s largest known trona deposit. China, by contrast, relies mostly on synthetic production using the Solvay process, which converts salt and limestone into sodium carbonate through a series of chemical reactions.
How It Differs From Baking Soda
Sodium carbonate and sodium bicarbonate (baking soda) are closely related but not interchangeable. The key difference is alkalinity. At the same concentration, a sodium carbonate solution reaches a pH of about 10.5, while sodium bicarbonate sits around 8.3. That makes washing soda roughly 100 times more alkaline than baking soda on the pH scale, which is logarithmic. In practical terms, washing soda is a much more aggressive cleaner and degreaser, while baking soda is gentle enough for cooking, brushing teeth, and neutralizing mild odors.
Safety and Handling
Sodium carbonate is not highly toxic, but it’s not harmless either. It’s classified as a mild skin irritant and causes serious eye irritation on contact. Prolonged skin exposure can cause dryness or redness, and getting the powder in your eyes can be painful and damaging without prompt rinsing. If you’re using it for cleaning or any hands-on project, wearing gloves and eye protection is a good idea.
The powder is also hygroscopic, meaning it absorbs moisture from the air and clumps over time. Store it in a sealed container in a cool, dry place. When cleaning up spills, avoid sweeping in a way that sends fine particles airborne, as inhaling the dust can irritate your nose and throat. Wiping it up with a damp cloth and ventilating the area is the safer approach.