UGNI BLANC
A white variety cultivated in the Southwest (and in Charantes under the name Saint-Émilion) that produces a rather acidic wine that does not age well and is perfectly suited for being distilled into Cognac brandies.

ULLAGE
Also known as topping off, a process that consists of regularly adding wine to each barrel during the maturation process in order to keep them full and avoid exposure to oxygen and particularly the development of acetic acid (vinegar flavor).

UNBALANCED
Said of a wine that lacks balance because one of its elements dominates the others. These elements include acidity, astringency, smoothness, alcohol, and residual sugar (for white wines). Acidity and astringency (tannins) reinforce one another, while acidity, sugar and smoothness cancel each another out.