Bi carb, short for bicarbonate of soda, is the common kitchen name for sodium bicarbonate (NaHCO3). It’s the fine white powder sold as baking soda in most grocery stores. It’s mildly alkaline when dissolved in water, which is what makes it so versatile: it reacts with acids, neutralizes odors, soothes heartburn, and makes baked goods rise. Whether you’ve heard it called bi carb, bicarb soda, baking soda, or bicarbonate of soda, it’s all the same single-ingredient compound.
How Bi Carb Works in Baking
Bi carb is a leavening agent, meaning it creates the gas bubbles that make cakes, muffins, and pancakes fluffy. The mechanism is straightforward: when sodium bicarbonate meets an acid, the two react and release carbon dioxide gas. Those tiny CO2 bubbles get trapped in the batter, causing it to expand as it bakes. The acid can come from buttermilk, yogurt, vinegar, lemon juice, honey, or even cocoa powder.
This is where bi carb differs from baking powder. Baking soda is pure sodium bicarbonate and needs you to supply the acid. Baking powder already contains sodium bicarbonate plus built-in acids. One of those acids reacts as soon as the powder gets wet, creating an initial rise. A second acid only activates when it reaches oven temperatures, giving baked goods a second lift during cooking. If a recipe calls for baking soda specifically, it’s because the batter already contains something acidic. Swapping in baking powder (or vice versa) without adjusting the recipe will change the texture and taste of the final product.
As an Antacid for Heartburn
Because bi carb is a mild base, it neutralizes stomach acid on contact. Half a teaspoon dissolved in a glass of water is a traditional home remedy for heartburn and sour stomach. The Mayo Clinic notes that adults can take 325 milligrams to 2 grams, one to four times a day, in tablet form. However, sodium bicarbonate should not be used as an antacid for more than two weeks. If heartburn keeps returning, it’s a sign of something that needs a different approach.
The relief is fast but temporary. Bi carb doesn’t reduce how much acid your stomach produces the way other heartburn treatments do. It simply reacts with whatever acid is already there.
Use in Sports Performance
During intense exercise, your muscles produce acid that contributes to the burning, fatiguing sensation that eventually forces you to slow down. Sodium bicarbonate acts as a buffer in the bloodstream, helping neutralize some of that acid and allowing athletes to sustain high-intensity effort slightly longer. The Australian Institute of Sport classifies it as a supported performance supplement.
The recommended protocol is 200 to 400 milligrams per kilogram of body weight, taken with a small carbohydrate-rich meal about two to two and a half hours before competition. For a 70-kilogram person, that works out to roughly 14 to 28 grams. At those doses, blood buffering capacity rises significantly and the effect lasts three to four hours. The main downside is gastrointestinal discomfort: bloating, nausea, and cramping are common, especially at higher doses. Spreading the intake across capsules over one to two hours and pairing it with food reduces those symptoms.
Why It Removes Odors
An open box of bi carb in the fridge is a classic deodorizing trick, and there’s real chemistry behind it. Many foul smells come from volatile acidic compounds, molecules light enough to drift into the air and reach your nose. Sodium bicarbonate neutralizes those acids, converting them into heavier, non-volatile salts that stay put instead of floating around. Butyric acid, for example, is the compound behind the smell of rancid butter. It vaporizes easily at relatively low temperatures. When bi carb reacts with it, it forms sodium butyrate, a solid that doesn’t release fumes until it reaches much higher temperatures. The odor molecule essentially gets locked down.
This same principle applies when you sprinkle bi carb on carpets, in shoes, or down drains. It’s most effective against acidic odors. For smells caused by alkaline compounds (like ammonia from cat urine), it’s less useful because the chemistry doesn’t favor the same neutralization reaction.
Medical Uses Beyond the Kitchen
Sodium bicarbonate plays a role in managing chronic kidney disease. Healthy kidneys regulate blood pH by retaining or excreting bicarbonate. When kidney function declines, the body can’t clear acid effectively, leading to a condition called metabolic acidosis, defined as blood bicarbonate levels persistently below 22 milliequivalents per liter. Left untreated, this accelerates kidney damage and contributes to bone loss and muscle wasting.
Oral sodium bicarbonate supplements are the standard treatment. They’re inexpensive, widely available, and generally well tolerated. The most common side effects are bloating and burping. Because sodium bicarbonate contains sodium, it can worsen high blood pressure or fluid retention in some people, so ongoing monitoring is part of the treatment.
Risks of Taking Too Much
Bi carb is safe in the small amounts used in cooking and occasional antacid use, but consuming large quantities is genuinely dangerous. Overdose symptoms include nausea, vomiting, diarrhea, muscle spasms, muscle weakness, irritability, and in severe cases, convulsions. If vomiting and diarrhea become uncontrolled, the resulting dehydration and electrolyte imbalances can trigger heart rhythm disturbances.
The core danger is pushing your blood pH too far in the alkaline direction, a condition called metabolic alkalosis. Your body’s enzymes and cellular processes depend on blood pH staying within a narrow range. People who chronically use bi carb for stomach problems or who take very large doses for perceived health benefits are at the greatest risk. This is why even over-the-counter antacid use is capped at two weeks, and why medical use in kidney disease requires regular blood tests to check bicarbonate levels and adjust dosing.
Baking Soda vs. Washing Soda
Bi carb is sometimes confused with washing soda, but they’re different compounds. Baking soda is sodium bicarbonate (NaHCO3). Washing soda is sodium carbonate (Na2CO3), a stronger alkaline substance used for heavy-duty cleaning and laundry. Washing soda is too caustic for food or medical use, so the two are not interchangeable. If a recipe or remedy calls for “bi carb” or “bicarb soda,” it always means baking soda, the one found in the baking aisle.