At dinner, a young Cabernet feels less sandpapery after some air. What changed most in the wine?

Answer: The tannin grip feels softer

The acidity mostly disappears — Not quite. Acidity is a separate part of wine structure, and air does not simply erase it. A young red can taste rounder after breathing because aromas integrate and the tannin grip feels less aggressive. If the real problem is high acid in a lean white, extra air may make it seem flatter rather than better.

The oak flavor fades fast — Not quite. Oak notes can seem better integrated after air, especially in a young red with vanilla or toast aromas. But the sandpaper feeling is mainly about mouthfeel, not oak smell. If the wine feels less abrasive, the useful change is the perceived tannin grip.

The tannin grip feels softer ✓ — Correct. At dinner-table timescales, the main change is sensory: the tannin grip feels less sharp, not gone. Oxygen exposure can make young tannic reds seem smoother while aromas integrate; deeper aging chemistry can modify tannins over longer periods. The useful surprise is that softening is not the wine becoming sweet.