It’s the little touches that separate the professional from the home bartender. Certainly, things like jigger technique and a flawless shake may be the most obvious, but in my mind, the fastest route to knowing if the person making your drinks is a pro is to ask them to make simple syrup. Most home bartenders, guided by countless bad recipes online, will reach for a saucepan. The person you really want to trust with your cocktails grabs a scale.
Simple syrup is just two ingredients—sugar and water—combined in equal parts by weight. This ratio creates a solution at the magical level 50 degrees Brix, meaning that 50 percent of the total weight is sugar. When building a cocktail with citrus like lime and lemon, which both measure 6 percent titratable acidity (a much more accurate measure of the flavor profile of a juice than pH, which is great for determining whether or not microorganisms will grow in a given juice but tells you very little about the taste on the palate), a 50 Brix syrup will balance either perfectly, leaving the finished drink neither too sweet nor too sour for the majority of drinkers. It’s why so many classic cocktail recipes in the sour family, like Daiquiris and Gimlets, follow that classic formula of two parts spirit to three-quarter parts each of citrus and simple.
Recipes should always start at that neutral position and move based on the goals of the drink and the wants and needs of the drinker. For example, I like Daiquiris that offer a big juicy flavor bomb with a high acid attack. Because I’m using a 50 Brix simple syrup, I know that adding an additional quarter-ounce of lime will get me there, because I know that my measurements are accurate. Cocktails are much more like baking than they are cooking—precision is the key to success and adding heat into the equation can put that precision in jeopardy.
Cooking simple syrup adds an extra variable to the mix—evaporation. As the syrup reaches a simmer or boil, water molecules are evaporating on the surface, leaving the syrup with a higher concentration of sugar. It may be negligible, but it’s a completely unnecessary step that only has potential to ruin your cocktails by leaving them too sweet without adjusting by taste on the fly. Sugar and water will dissolve easily at room temperature with only some stirring or shaking. Just combine them in equal parts on a scale in a sealable container like a Mason jar and shake until it’s dissolved. If you really need the syrup right now, then toss the sugar and water in a blender. It’s even faster than heating the water and guaranteed to not ruin your solution’s balance.
Of course, there are exceptions to every rule. For example, it can often be prudent to introduce heat for better flavor extraction when infusing spices, herbs, citrus peels, or any other fruit or vegetable in a syrup. In these cases, I’ll watch the mixture like a hawk, and cut the heat as soon as I see the first sign of a simmer. By doing so, you’ll avoid overextracting the spices, and for added intensity you can always let the mixture sit off the heat, tasting regularly, until it reaches the desired flavor.
In a professional bar setting, I would be checking every syrup with a refractometer to make sure it’s at the desired Brix. I would never ask the same from a home bartender. But please, for your cocktail’s sake, don’t cook your simple.