acidify

Acidify is a verb meaning to make something more acidic or to lower its pH. In chemistry, acidity is quantified by the concentration of hydrogen ions in a solution; acidification increases this concentration or shifts the equilibrium toward proton donation. The term can describe processes that cause a substance to become acidic, or the act of adjusting a solution to a desired acidic level.

Acidification is commonly achieved by adding acids, such as mineral acids (hydrochloric, sulfuric) or organic acids (acetic, citric). It can also occur through reactions that generate carbonic, sulfurous, or organic acids, or by dissolving carbon dioxide in water, which forms carbonic acid. In biological systems, metabolism and fermentation often produce acids (for example, lactic acid by lactic acid bacteria), which lowers surrounding pH.

Environmental acidification refers to the increase in acidity of soils and surface waters due to acid deposition from burning fossil fuels, rainwater with dissolved sulfuric and nitric acids, and industrial discharges. Acidification can mobilize toxic metals, deplete buffering minerals, alter nutrient availability, and affect organisms, particularly in freshwater and forest ecosystems.

Practically, acidification is used in food and beverage processing to control texture and microbial growth, in wine and fermentation to influence flavor and stability, and in laboratory workflows to preserve samples or enable certain reactions. It also plays a role in medicine and biology for adjusting bladder urine pH, gastric juice, or intracellular environments in cell biology experiments.

Acidity is measured on the pH scale; many processes also rely on buffering to resist pH change. Safety concerns include handling acids, which can cause burns and tissue damage, and the environmental risks of excessive acidification.