Châteauneuf du Pape Magnum
A magnum contains 1.5 L of wine, the equivalent of 2 bottles. It is a bottle that is mainly used for so-called "long-keeping" wines such as the red wines of Châteauneuf du Pape, but also for champagnes, and today rosé wines. Everyone has heard "a magnum is better". Yes but why ?
Aside from the festive nature, and the fact that presenting a magnum of Châteauneuf du Pape red at the table, or offering a magnum, “is impressive”, the good reasons are above all technical. The effect of large volume storage, starting with the magnum size, on the aging of a red wine is, ultimately, easy to understand. The bigger the bottle, the more wine there is: the greater the volume of wine, the more likely it is to preserve its original characteristics. It will be said that, compared to the same red wine in a 75 cl bottle, a Châteauneuf du Pape red wine kept in a magnum will stay younger for longer, retaining a better quality of fruit in its flavors. The greater thermal inertia in a magnum of red wine helps slow down some of the oxidative effects of aging on wine.
Finally, the wine-air ratio is lower in a magnum of red wine, and therefore aging is slower. Conversely, when the magnum is open, a red wine, Châteauneuf du Pape or other, oxygenates more quickly during service because the diameter of a magnum is larger than that of a 75cl. You can thus, for example, taste the same red wine in two services during a meal: the 1st half of the magnum is decanted and reserved for the cheeses, the aeration will be greater than on the other half which is oxygenated in the bottle, and which will be served with the main course.