Noilly Prat (French pronunciation: [nwa.ji pʁat]) is a brand of vermouth from France, owned by the Italian company Martini & Rossi, which is a subsidiary of Bacardi.
Noilly Prat is made exclusively from white grape varieties grown in the Marseillan area, principally Picpoul de Pinet and Clairette.
The wine stays in these casks for 8 months, maturing and absorbing the flavour of the wood, before being transferred to smaller oak barrels which are taken outside and left for a year.
A small quantity of Mistelle (grape juice and alcohol) is added to the wines in order to soften them, along with a dash of fruit essence to accentuate their flavour.
In the oak casks, a process of maceration, supposedly unique to Noilly Prat, takes place over a period of three weeks.
The exact mix of herbs and spices that goes into Noilly Prat is a closely guarded secret, but includes camomile, bitter orange peel, nutmeg, centaury (yellow gentian), coriander, and cloves.
Over the years, the American preference for "extra dry" martinis led to the switch from gin to vodka, and to drastically reducing the flavour and quantity of the vermouth employed.