Baking soda, or sodium bicarbonate (NaHCO3), is a mildly alkaline white powder with a unique combination of chemical properties that make it useful far beyond the kitchen. It reacts with acids to produce carbon dioxide gas, acts as a pH buffer, gently abrades surfaces, and neutralizes odors. These properties explain why the same simple compound shows up in recipes, cleaning routines, medicine cabinets, and athletic training.
Chemical Makeup
Sodium bicarbonate is made of sodium, hydrogen, carbon, and oxygen, with a molecular weight of about 84 g/mol. In water, it separates into a positively charged sodium ion and a negatively charged bicarbonate ion. That bicarbonate ion is the workhorse behind most of baking soda’s useful properties: it can both accept and donate protons, meaning it reacts with acids and bases alike. This dual reactivity is what makes baking soda a buffer, a substance that resists sharp swings in pH.
Dissolved in water, baking soda creates a mildly alkaline solution with a pH around 8.3. It’s soluble enough to dissolve readily at room temperature, though it dissolves less easily than table salt. At higher temperatures, it breaks down into sodium carbonate, water, and carbon dioxide gas, a decomposition that begins slowly at lower temperatures and becomes significant as heat climbs toward 100°C and above.
How It Works in Baking
When baking soda meets an acid, like buttermilk, lemon juice, vinegar, or cream of tartar, it produces carbon dioxide bubbles almost immediately. Those bubbles get trapped in batter or dough, causing the mixture to rise. This is why recipes that rely on baking soda (rather than yeast) tend to call for an acidic ingredient and why you need to get the batter into the oven quickly, before the gas escapes.
Heat provides a second leavening boost. As the temperature inside your oven rises, the remaining baking soda that didn’t react with acid decomposes on its own, releasing additional carbon dioxide. This thermal decomposition is why baking soda can still produce some lift even in recipes without an obvious acid source, though the results are less predictable and can leave a soapy, metallic taste from the leftover sodium carbonate.
Buffering and Acid Neutralization
The same acid-base reaction that makes cakes rise also makes baking soda effective at neutralizing stomach acid. When sodium bicarbonate meets the hydrochloric acid in your stomach, it produces salt, water, and carbon dioxide. The reaction is fast, which is why people have used it as a quick-acting antacid for generations. The carbon dioxide does cause belching, an expected side effect.
This buffering capacity extends to the blood. Your body naturally uses bicarbonate to regulate blood pH, keeping it in a narrow range. In people with chronic kidney disease whose blood becomes too acidic (a condition called metabolic acidosis), oral sodium bicarbonate is sometimes used to help bring levels back up. One clinical trial of 134 adults with reduced kidney function found that those taking about 1.2 grams of sodium bicarbonate daily were less likely to experience rapid decline in kidney function over two years compared to a control group. The evidence remains limited, though, and this is an area where dosing and patient selection matter enormously.
Odor Neutralization
Baking soda’s reputation as a deodorizer isn’t just folk wisdom. Because it acts as a buffer that can neutralize both acidic and alkaline substances, it chemically reacts with a wide range of smelly compounds rather than simply masking them. Many common household odors are volatile fatty acids (acidic) or ammonia-based compounds (alkaline). Baking soda can interact with both types, shifting their pH enough to convert them into less volatile, less odorous forms.
This is why an open box in the fridge, a sprinkle in shoes, or a dusting over organic waste in a compost bin can reduce smell. Research on food waste found that baking soda helped control the release of both acidic and ammonia-based odors from decomposing organic matter, where moisture levels of 75 to 85 percent and organic content above 85 percent would otherwise produce strong smells.
Mild Abrasiveness
As a fine crystalline powder, baking soda is abrasive enough to scrub away surface grime but soft enough that it won’t scratch glass, stainless steel, or ceramic. On the Mohs hardness scale, it sits at about 2.5, softer than most household surfaces. This makes it a practical cleaning agent for stovetops, sinks, and teeth. Mixed with a small amount of water into a paste, it provides gentle mechanical cleaning action while its alkalinity helps dissolve grease and protein-based stains.
Athletic Performance
During intense exercise, your muscles produce hydrogen ions that lower pH and contribute to the burning sensation and fatigue you feel. Because sodium bicarbonate increases the blood’s buffering capacity, athletes use it to delay that acid buildup. A position statement from the International Society of Sports Nutrition confirms that doses of 200 to 500 mg per kilogram of body weight improve performance in high-intensity activities lasting one to seven minutes, including cycling, running, swimming, rowing, and combat sports.
The optimal single dose appears to be 300 mg per kilogram, roughly 21 grams for a 70-kilogram person. Higher doses don’t add performance benefits and are more likely to cause gastrointestinal distress, including nausea, bloating, and diarrhea. This is one of the most well-supported legal ergogenic aids in sports nutrition, though the side effects are a real tradeoff that limits its practical use for many people.
Safety Limits
Baking soda is safe in small amounts, but it’s possible to overdo it. For adults under 60, the maximum recommended intake as an antacid is about 15.6 grams per day, taken in divided doses. For adults 60 and older, that ceiling drops to roughly 7.8 grams per day. Exceeding these amounts, or taking large doses too quickly, can push your blood pH too high. This condition, called metabolic alkalosis, reduces the level of available calcium in your blood and in severe cases can cause muscle spasms and cramping.
People who already have alkaline blood chemistry, whether from a medical condition or from hyperventilation, should avoid supplemental sodium bicarbonate entirely. The sodium content is also worth noting: each teaspoon of baking soda contains over 1,200 mg of sodium, more than half the daily limit recommended for most adults. Regular use as an antacid can add up quickly for anyone watching their salt intake or managing high blood pressure.