Term
Oxidation
ox-ih-DAY-shun
Air as friend and enemy
Oxygen can polish a wine in barrel or wreck it in a forgotten bottle. Knowing which you are looking at is a core somm skill.
Unwanted oxidation: walnuts, sherry-like notes in a wine that should be fresh, browned color in a young white, flat fruit. A bottle left open too long, a bad closure, a tired old white.
Intentional oxidation: Oloroso sherry, Madeira, some white Rioja, certain Jura vins jaunes, oxidative Chenin. These wines are built for air. They smell of nuts, broth, and dried fruit on purpose.
Reduction is the opposite problem — too little oxygen, struck match, rotten egg. A splash in a decanter usually helps. Oxidation does not reverse. When in doubt, ask whether the style is supposed to taste like Sherry.
