© Denzil Green
Italian Vermouth, when used without any qualification, means "red" vermouth. All vermouth starts as white wine. To make it red and to add flavouring, a caramel solution is added, along with additional flavourings.
There are two main brands of Italian Vermouth; Martini & Rossi's is more lemony tasting while Cinzano is more herb tasting. In Italy, however, the most popular brand (as of 2004) is actually called "Stock."
Red is far sweeter than white, and its 18% alcohol content is 2% higher than white's.
Red Vermouth is a bit harder to use in cooking than White Vermouth is: while White Vermouth, being dry, can be swapped in for white wine, red is a bit tricker to just swap in for red wine as it is so sweet. It is great for carmelizing onions with, and for use in other dishes where its sweetness would be appropriate.
A sweet red wine, perhaps with a dash of Angostura bitters to pick up the bitter notes that would have been in the vermouth.
Store indefinitely at room temperature before and after opening.
If you offer someone a drink and they ask for a "Gin and It", they mean a drink of 1 part gin, 1 part Italian vermouth. Some might argue that without meaning to, they are also showing their age.