Now that you've mixed some cocktails that only require a base, it's time to start mixing alcohol with, well, more alcohol. Vermouth is a fortified wine that's been flavoured with botanicals like roots, bark, flowers, seeds, herbs and spices.
Originally sipped straight in Italy, it became a bartender's staple in the 1800s and remains one today. Vermouth traditionally is available in sweet (red) and dry (white), but today many variations are available. Start off with one bottle of sweet vermouth and one of dry (we recommend Dolin Rouge and Dry).
A word of caution: as vermouth is based on wine, it has a shorter shelf life than your bases. Most vermouth will last 4-6 weeks; you can extend the shelf life by sealing the bottle after first use and keeping it in the fridge. If you can purchase half-bottles more frequently, your drinks will taste better.