The pH scale is a measure used to determine how acidic or basic a substance is, with a neutral value of 7.0 sitting exactly in the middle. Values below 7.0 are considered acidic, while values above 7.0 are considered basic or alkaline. Butter, the concentrated fat product made from churning cream, is classified as slightly acidic, although its pH is remarkably close to neutral.
The Acidic Nature of Butter
The pH of sweet cream butter typically falls within a narrow range of 6.1 to 6.7, placing it just below the neutral point. This slight acidity means butter is not a highly acidic food like citrus fruits or vinegar, but it is technically classified as acidic. The initial cream used to make butter has a similar pH, and the churning process retains this near-neutral state.
Sweet cream butter is made from unfermented fresh cream, resulting in a higher pH, close to fresh milk. Cultured butter is made from cream ripened with bacterial cultures, similar to buttermilk. These cultures produce lactic acid, which significantly lowers the butter’s pH, often resulting in an acidic range of 4.4 to 5.0. This method creates the distinct, tangy flavor of cultured butter.
Chemical Components Determining pH
The slight acidity in uncultured butter is linked to the presence of free fatty acids. While milk fat is mostly composed of neutral triglycerides, the small amount of free fatty acids present in the water portion contributes to the overall pH. These organic acids, such as butyric acid, naturally lower the pH of the aqueous phase.
Butyric acid, a short-chain fatty acid, is a component of butter fat, making up about three to four percent of the total fat. While it is mostly bound within triglycerides, it can be liberated by hydrolysis as butter ages or goes rancid. The release of this acid lowers the pH further and produces the characteristic strong odor of spoiled butter. In cultured butter, the acidity is predominantly due to the lactic acid produced by bacterial fermentation.
Practical Implications of Butter’s pH
Butter’s near-neutral pH is advantageous for its use in cooking and baking, providing chemical stability in recipes. Since it is not strongly acidic, butter does not typically react aggressively with alkaline ingredients, such as baking soda, used as a leavening agent. This stability allows butter to be used universally without causing premature or excessive rising.
When considering digestion and health, butter is generally classified as a low-acid food. The vast majority of butter is fat, which does not contain the high concentration of free acid molecules found in foods that commonly trigger acid reflux. Any potential digestive discomfort related to butter is usually attributed to its high fat content, which can delay stomach emptying, rather than its minor acidic pH level.