lemon slice

Acids, like lemon juice, add a tangy or sour note in baking.


What are Acids?

Acids plays a vital role in baking. In bread, acids affect yeast fermentation and extend shelf life through the use of vinegar (acetic acids) and cultured wheat.  In batters and cakes, acids affect the chemical leavening.

An acid is defined as a substance or compound dissolvable in water that release Hydrogen ions, or H+ ions into a surrounding solution. Acidic substances can be identified via litmus paper. If a sample of litmus paper exhibits a red color after contacting a substance, the substance is indeed an acid. In regards to the pH scale, acids have a pH value lower than 7. The addition of an acidic substance into a primarily basic substance causes the basic substance to weaken and vice versa.

“Acid” is a Latin term translating to “sour”. Sour is a very appropriate term to describe acid because any acidic substance has a sour taste such as lemon juice or vinegar.


In baking, acids add a tangy or sour note when such flavors are desired. Sour milk products, lemon juice, and fruit products are acids used in the baking industry to enhance flavor and add a sharp taste, or balance flavors of sweetness such as in sourdough bread, raisin bread, and turnovers or pastries.

If an acidic ingredient is included in a recipe, an alkali ingredient, otherwise known as a base, must balance the substance out. Baking soda is the most commonly used alkali in baking. In recipes containing an acidic ingredient and a balancing agent of a base, they act as a leavening agent, increasing the volume of the baked good. Breads, cakes, muffins, and pancakes are baked goods where such a chemical reaction is exhibited. Ingredients such as lemon or lime juice, apple cider vinegar, buttermilk, honey, coffee or cocoa powders are common ingredients that are acids used in the world of baking.


  • Acetic Acid: The prime ingredient in vinegar. Created by reacting ethyl alcohol and bacteria or via the reaction between methyl alcohol and carbon dioxide. In baking, acetic acid is what gives vinegars their distinctive sour taste. When vinegar is used in baking such as apple cider vinegar, the combination of baking soda and vinegar creates a chemical reaction leading to the production of carbon dioxide gas. The carbon dioxide gas bubbles expand in the baked good causing rise.
  • Tartaric Acid: Is a naturally occurring product. Commercially, it is obtained as a by-product from wine making. It is commonly added in confectioneries to regulate the pH in the food. In bakery products, it may be used in icings and fillings as a chelating agent. It is also found in cream of tartar.
  • Citric Acid: Naturally found in many fruits, mainly sour fruit such as grapefruits, oranges, limes, lemons, gooseberries, plums, pineapples and peaches. Used primarily as a flavoring or firming agent. Citric acid, or sour salts, are used in the production of sourdough bread, assisting in creating the distinct sourdough flavor.