When it comes to cocktail shakers, most home bartenders kit themselves out with a Classic Shaker, also known as a Cobbler Shaker. These have three pieces: a tumbler, a cover with a strainer embedded in it and a cap for on top.

Most professional bartenders, however, will use what’s known as a Boston Shaker. In the pic at left, you can see famed 19th century bartender Harry Johnson using one to strain six drinks at once.

A Boston Shaker consists of two tumblers, one glass and one of stainless steel. The former typically holds 500 ml, the latter 900 ml. The trick here is that, if they are of decent quality and the right size, the glass half will form an airtight seal with the stainless steel half when they are tapped together.

To mix a cocktail using a Boston Shaker, build the drink in the glass tumbler first. Then add  ice to the steel half and pour the cocktail over it. Place the glass half into the steel half and give it a firm tap (more of a whap, really) with the palm of your hand. Shake in a vertical arc with the stainless steel tumbler on the bottom and a hand on each.

Shake hard and vigorously. A Boston Shaker should sound like a tommy gun.

Once the cocktail is sufficiently cooled, hold the shaker in one hand — I find this part works best if you keep most of your fingers wrapped around the stainless portion but keep one or two on the glass part to steady it. Give the spot on the stainless half where the two tumblers meet a good solid whack with your free hand. That should break the vacuum and you’ll be able to separate them and strain the cocktail.

As for the strainer, the one you’ll need is called a Hawthorne Strainer. You’ve seen these. They look like a metal ping pong paddles with holes and a spring around the top edge.

Now, you’re probably wondering why bother going to all the trouble of a Boston Shaker? Well, the chief reason is that a Boston Shaker is much easier to clean than a Cobbler. Also, the glass half can be used as an attractive serving vessel on its own as these are often embellished with fetching, comical or, occasionally, racy illustrations.

But more than anything, the prime attraction of the Boston Shaker is that machine gun rattle.