Ruby port reduced to a glossy sweet-savory syrup — duck breast's classical partner, and dangerous drizzled near blue cheese.
Does the alcohol really cook off?
Mostly. A hard 2–3 minute boil drives off the harsh raw alcohol; long simmering removes more. A splash of flavor compounds carried by the wine stays behind — that's the point.
Which wine should I use?
One you would drink, but nothing precious. For reds: dry, mid-weight, low-oak (Côtes du Rhône energy). For whites: dry and crisp (Sauvignon Blanc, unoaked Chardonnay). Sweet or heavily oaked wines concentrate into syrup or bitterness.
How do I know when it's reduced enough?
Drag a spoon across the pan: the sauce should hold a brief trail. Nappe — coating the back of a spoon — is the classic test. It thickens further as it cools, so stop a shade early.