92 pts - Wine Advocate
Opus One's 1991 is a gorgeously rich, opaque ruby/purple-colored wine with a knock-out nose of smoke, cassis, vanilla, and a whiff of herbs and licorice. Full-bodied, with surprisingly supple, concentrated, chocolatey, cassis, and blackcurrant flavors that ooze across the palate, this voluptuously-textured example of Opus One is atypical in a vintage that produced so many backward wines. There is no question the wine possesses plenty of tannin, but it is admirably concealed by the copious quantities of concentrated fruit. This Opus can be drunk now as well as over the next 15+ years.
97 pts - Wine Spectator
This monumental wine has enormous richness, depth and polish, brimming with ripe, juicy plum, cherry, currant and cedary oak. Should be uncommonly long-lived. Delicious.--Opus One vertical. Drink now through 2012. 23,000 cases made. — JL
92 pts - Vinous
The 1991 Opus One is completely different from its predecessors. The style is decidedly rich, voluptuous and opulent for the era. Sweet silky tannins support a creamy, expressive finish in a wine that is very much built on texture. Today the 1991 is showing beautifully. The slightly advancing aromatics suggest it is best enjoyed over the next decade. The 1991 is a racy Opus One long on personality. The blend is 93% Cabernet Sauvignon, 6% Cabernet Franc and 1% Merlot.- Antonio Galloni (6/213)