- Potassium bicarbonate (chemical formula KHCO₃) is a white, crystalline, water-soluble compound composed of potassium (K⁺), hydrogen (H⁺), carbon, and oxygen, forming the bicarbonate ion (HCO₃⁻). It is a mildly alkaline salt, similar in appearance and function to sodium bicarbonate (baking soda), but with potassium as the cation instead of sodium. Potassium bicarbonate is commonly used in agriculture, food production, fire suppression, and as a dietary supplement, particularly where low-sodium alternatives are desired.
- In agriculture, potassium bicarbonate is valued as both a fungicide and a potassium source for plants. It is often used to control fungal diseases like powdery mildew, particularly on grapes, cucurbits, and ornamental plants. Its mode of action involves altering the pH on leaf surfaces, making them less hospitable to fungal growth, while also providing potassium—a critical nutrient for plant metabolism, water regulation, and stress tolerance. Since it leaves no toxic residue and breaks down into naturally occurring substances, potassium bicarbonate is approved for use in organic farming in many countries.
- In the food industry, potassium bicarbonate is used as a leavening agent in baked goods, serving as a low-sodium alternative to baking soda. It releases carbon dioxide when combined with an acid, helping doughs and batters rise. This makes it useful for individuals on sodium-restricted diets, where sodium bicarbonate might otherwise be limited. It is listed as E501(ii) when used as a food additive and can be found in baking powders, effervescent beverages, and dietary supplements.
- Potassium bicarbonate is also employed in fire suppression, particularly in dry chemical fire extinguishers designed for Class B and C fires (flammable liquids and electrical equipment). It acts by releasing carbon dioxide and disrupting the combustion process, making it effective in high-risk environments such as industrial settings and commercial kitchens.
- In the realm of health and medicine, potassium bicarbonate may be prescribed as an alkalizing agent to help correct metabolic acidosis or to replenish potassium levels in patients with hypokalemia. It can also be used as a buffer in pharmaceutical formulations and laboratory applications due to its pH-stabilizing properties.
- While generally non-toxic at low concentrations, excessive intake of potassium bicarbonate—especially as a supplement—can lead to hyperkalemia (elevated blood potassium levels), which may cause muscle weakness, arrhythmias, or more serious cardiac complications, particularly in individuals with kidney impairment.
