You should keep it out of your liquor cabinet
“It may begin to turn four to six weeks after opening,” says our expert. “To preserve your vermouth after you've opened the bottle, treat it like you would an open bottle of wine and store it in a refrigerator rather than cabinet.”
The flavor changes over time
Again, put it in your fridge. But once you do, the flavors will change as it sits. “The liquid will evolve in the bottle, seeing as vermouth is wine based,” Leboulengé says. “We recommend enjoying Vermouth Royal, especially the extra dry, within a month or two to ensure the product’s quality. After this time, it may start to lose its organoleptic (aka taste and odor) characteristics.”
It’s more versatile than you think
Sure, your local cocktail bar is stocked with vermouths for mixing into Manhattans, Negronis, and other cocktails, but it’s also technically an aperitif, which means you shouldn’t feel too weird taking a pull of straight vermouth once in a while, especially before dinner. It’s also great for cooking: both for drinking while in the kitchen and as an ingredient.