The Scientific Reason Grenadine Sinks In Some Cocktails

Grenadine is an incredibly versatile, non-alcoholic syrup with the power to turn even the most basic drinks into delicious cocktails, such as the Queen Mary, made from light beer and grenadine. It also lends its rich, pomegranate and orange flavors to several alcohol-free concoctions, like the Grown-Up Shirley Temple Mocktail.

If you've ever gone out for brunch with friends, you've likely seen the vibrant red and orange layers of the iconic tequila sunrise cocktail. When making the drink, the order in which you add ingredients matters. Orange juice and tequila are added first, then grenadine is slowly poured in, sometimes cascaded down a bar spoon inserted into the glass. Despite being the last ingredient added to the cocktail, the grenadine quickly sinks to the bottom, creating the classic "sunrise" color gradient we all know and love. But why?

There's a scientific reason for this reaction: Grenadine is a very dense liquid, which gives it its signature ability to sink to the bottom of most drinks. Its high sugar content with little water also boosts its density, giving it a higher specific gravity than most other cocktail ingredients.

A liquid's density is determined by its specific gravity, which Merriam-Webster defines as "the ratio of the density of a substance to the density of some substance (such as pure water) taken as a standard when both densities are obtained by weighing in air." Essentially, a liquid's weight is measured and compared to that of water of the same volume. If the liquid weighs less than water, it has a lower specific gravity, and vice versa. Water has a gravity of 1.0, so a liquid with a higher gravity will sink when poured into pure water. Grenadine has a gravity of 1.18, although that can fluctuate depending on the brand.

Sugar also plays a major part in determining a liquid's density. For example, low-sugar, high-proof liqueurs like triple sec will float on top of high-sugar, low-proof liqueurs like Butterscotch Schnapps. Pure, high-proof spirits like whiskey, tequila, and vodka all have lower specific gravities than water, meaning they will float on top of nearly every layered cocktail. This is why you might be hit with a strong alcoholic flavor if you sip from the top of a layered drink. Grenadine itself is jam-packed with sugar and little water content, making it denser than most other ingredients at the bar.