Both are bicarbonate base and with similar functions in food, but we always think of baking soda when it comes to bicarbonate.

Potassium bicarbonate does not contain any sodium and can be used as a substitute of sodium bicarbonate (baking soda) to lower the sodium content.

Their difference is that potassium bicarbonate is used less than the latter in baking as it brings an undesirable taste, and more quantity is needed to produce equal carbon dioxide. Plus, it is highly hygroscopic, this property makes it difficult to store.

Soda water
Soda water, also known as carbonated water or sparkling water, is water forced with carbon dioxide under pressure for the purpose of fizz and refreshment.

Potassium bicarbonate can be added to bottled water to enhance the water taste (2) by increasing the PH. You can find this ingredient in Coca Cola’s of Seagrams Club Soda (3) and Smartwater Sparkling (4)

Winemaking
Potassium bicarbonate is an alkaline that can be used as a pH regulator to reduce the acidic taste (tartaric acid) in wine and therefore improve the flavor in winemaking. It can also be added to your coffee to make it less acidic with the same property.

Pharmaceuticals
It can be used as a potassium electrolyte replenisher to prevent or treat low blood levels of potassium (hypokalemia), also an antacid to neutralize gastric acid.

Plus, it acts as an excipient in effervescent tablets. Different from ordinary tablets, effervescent tablets use the combination of acidulants (e.g. citric acid, malic acid) and carbonate or bicarbonate salts (e.g. potassium bicarbonate) as a disintegrant.

The mechanism is that when place a effervescent tablet in water, the reaction between acidulents and alkalines generates and produces a large amount of carbon dioxide gas, the phenomenon like boiling. This process makes the tablet disintegrate and the active ingredients dissolved in vitro quickly, which results in a quick absorption of active ingredients into the blood, thereby achieving a quick action and high-efficiency of a drug in our body.

Fungicides
It is used as a fungicide and best suitable to control powdery mildew diseases and useful in prevention of other diseases (for example, alternaria, anthracnose, black dot root rot, botrytis blossom and twig blight, botrytis bunch rot) on various vegetables and fruits. (5)

It functions as an active ingredient in pesticide products by diluting with water and sprayed on foliage of plants.

Fertilizer
Potassium hydrogen carbonate can be used to reduce acidity in soil and help crop growth in agricultural applications. Also improve the soil absorption of potassium, and synergy with phosphate fertilizers.

Feed
It is added as a nutritional supplement to animal feed to prevent potassium deficiencies and increase feed consumption and therefore enhance weight gain in livestock. It is also a rumen buffer in the form of bicarbonate.

Fire extinguisher
Potassium bicarbonate is a dry chemical fire extinguisher which is primarily used on Class B (flammable liquids and gases) and Class C (electrical) fires. (6)

The mechanism of potassium bicarbonate puts off fire mainly by the way of releasing carbon dioxide under pressure, which reduces the oxygen concentration around combustibles and in addition, it will quickly evaporate from the condition from liquid to gas, and thus absorb some heat from the surroundings to cool down the burning objects.