One of the best parts about sitting at a bar is watching professional bartenders shake cocktails. Every bartender has their own signature style and no two shakes are exactly alike. But if there isn't one "correct" technique, then what makes a good shake?Before answering that question, it's important to understand the purpose of shaking a cocktail, which is to chill and slightly dilute the drink you're making. Shaking will also aerate the beverage and help the ingredients fully combine. This is especially crucial when the ingredients have varying densities (e.g. cocktails that use egg whites) and are not easily soluble in one another. But to answer the original questions of "what makes a good shake," we asked the Yardbird and RŌNIN bartenders for their #SundaysProTips when bartending at home.How Vigorous Should My Shake Be?It's essential to give the movement some force and power, but there’s a common misconception that the best shake is the most vigorous one. It really depends on the situation - you'll probably need a more gentle shake if you don’t want to bruise your gin, if you want to keep some texture in your bloody mary, or if you’re shaking a cocktail that is traditionally stirred, etc. You gotta know what your end goal is.How Long Should I Shake a Cocktail For?Typically, a cocktail requires a vigorous shake for approximately 12 seconds. For cocktails that use eggs or cream, which don't combine easily with other ingredients, you may need to shake for longer.What is the Ideal Motion?There’s no right or wrong way per se - that’s why every bartender develops their own style. But our pro-tip is to have a slight twist in your wrist rather than violently shaking in an up-and-down motion (which breaks the ice much quicker and can over-dilute your drink). This twisting motion requires less effort, aids in aeration, and allows the ice to fully incorporate into the drink, rather than just hitting the top and bottom.How Much Ice Should I Use?Generally speaking, fill at least half of your shaker with ice. If you’re stingy with ice, it will melt too quickly and your drink will come out too diluted.What Should I Do if I Don’t Own a Shaker?A great hack is to use a mason jar with a lid. But if you’re passionate about home bartending, it really is worth investing in a 3-piece cobbler shaker or a 2-piece Boston shaker.