Adulteration in wine refers to the illegal practice of altering wine’s compositions-such as adding artificial color, sugar, or other substances-to deceive consumers or mimic higher-quality products. It has been a form of wine fraud for centuries, undermining trust in producers and markets alike. To combat this, many countries have developed controlled appellation systems (like France’s AOC, Italy’s DOC/DOCG, or Spain’s DO), which regulate everything from grape varieties and geographic origin to yields and production methods. These systems help protect authenticity and quality, offering consumers greater assurance that what's in the bottle reflects its label and origin truthfully.