Acidification is the winemaking practice of increasing the acidity of grape must or wine by adding an approved acid, most commonly tartaric acid. It may be used when grapes have low natural acidity, often because of warm growing conditions or very ripe fruit. The aim is to improve freshness, balance, microbial stability and the wine’s overall structure.
Grapes naturally contain several acids, particularly tartaric and malic acid. In warm climates or hot vintages, grapes may lose acidity as they ripen, resulting in must that can produce a broad, soft or flat wine. A carefully calculated acid addition can help restore balance and support the desired style. The need and permitted methods vary by region and wine category.
Tartaric acid is commonly used because it is a major natural acid in grapes and is relatively stable in wine. Other acids may be permitted for specific purposes and under local regulations. Winemakers usually conduct laboratory analysis and bench trials before making an addition, because the effect depends on pH, titratable acidity, potassium level and the composition of the must or wine.
Acidification increases acidity, while deacidification reduces acidity, often using permitted chemical or physical methods. Both are regulated in many wine regions and may be restricted by appellation or vintage conditions.
Example: a winery in a warm region may add a measured amount of tartaric acid to a low-acid must to improve freshness and balance before fermentation.
Chef’s note: acidification is a controlled cellar adjustment, not the same as adding lemon juice to finished wine. It must follow local winemaking regulations and be based on analysis and trials.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
