Muddler
The muddler is an important bar tool for anybody wishing to really make the best classic cocktails. You might commonly see it used by bartenders in a glass full of ice to mash up some lemons or limes when used in the construction of a drink such as a Lemon Drop, Cosmopolitan or a Margarita. In the construction of a classic cocktail however it is used prior to adding any ice as a way to crush an ingredient in order to get it to release its oils and other flavor components.
For an Old Fashioned, you will use it to both extract the flavors from a half orange wheel, as well as to mix the sugar and bitters in the glass. In the preparation of a Mint Julep it will be used to crush the mint and simple syrup together in order to bring out a lovely mint flavor that then blends with the syrup. When you make a Caipirinha you will crush the lime quarters together with the granulated sugar, this will not only juice the limes, but it will also grind the sugar against the lime skin to better extract it's flavors and add it to the drink.
The picture shown on the right, is just a few of the muddlers that I've gathered over the years, They are all shown to scale, with the largest ones in the picture being just a little over 10 inches, with the smallest one coming in at half that size.
The first muddler on the left, is one that was custom made by Chris Gallagher, who will hopefully soon be making them commercially available.
The second two muddlers in the picture are the more common style of muddlers that you should be able to readily find at most bar supply stores as well as some well-stocked kitchen stores.
The muddler in the middle is a marketing muddler, branded with "Cachaça Pitu", and the one to the right of it is an antique marketing muddler with "Abbott's Aged Bitters" stamped on it.
Also in the picture, the "working" ends of the muddlers (ie. the end that is muddled against the product) is at the bottom of the image... far too often I see bartenders using the wrong end of the muddler, while technically either end can get the job done, it just shows a certain lack of knowlege about the tool to use the wrong end.
Where and What to Buy
Years ago, it was hard to find muddlers, and so my first muddler was a long wooden spoon that I sawed off just below where the spoon started forming. This gave me a reasonably good flat surface to use for muddling drinks, and in all truth worked very well indeed. So if you can't find a muddler, they are easy enough to make.
These days however it appears to be far easier to find good quality, and fairly inexpensive, muddlers. Here are just a few of the online sites that you can purchase from:
Instawares.com
Deuster
BigTray