Short definition
A 1.5-liter bottle holding twice the standard 750ml, considered the ideal format for aging wine and serving groups.
A magnum holds the equivalent of two standard bottles. The larger volume relative to the cork means slower, more even aging — which is why collectors favor magnums for wines they plan to cellar for decades. At dinner, magnums are festive and practical for groups of four to six. Many restaurants stock magnums for celebrations. Expect to pay slightly more than double the standard bottle price, but the wine inside is often in better condition.