Why the Shape and Size of Ice in Your Drink Matters

An extra-large, crystal-clear ice cube is perfect for an Old Fashioned, but it would do a cup of cola no favors. Likewise, the crushed ice that makes a Big Gulp so cool and refreshing on a hot day would result in a watery, weak Negroni. One size or shape of ice isn’t better than another. Different ice performs different functions for different drinks. 

We all know that ice chills and dilutes our drinks, but let’s take a scientific look at how it can affect taste and texture. Two important concepts should be kept in mind. 

Melting matters

When you drop ice into your drink, it warms up and then melts. A certain amount of energy is needed to warm up the ice, but much greater energy is required to convert solid ice into meltwater. That energy is taken from the surrounding liquid, which cools that liquid. So, your drink gets a bit colder from warming ice, but becomes chilled much more from melting ice. 

That melted ice will dilute the drink with water, of course. Dave Arnold, author of the scientific bartending book Liquid Intelligence: The Art and Science of the Perfect Cocktail, says that from a practical standpoint, “there is no chilling without dilution.”

The more ice that melts, the more that a drink cools off. That’s why the giant cube of ice is the wrong choice for a room-temperature soda. It just doesn’t melt fast enough.

Surface area and volume

Ice melts at its surface, so the more ice surface that touches your beverage, the more it can cool at one time. Picture a great big ice cube sitting in a glass of liquid. If you crack that cube in half, more surface touches the liquid. The two pieces of ice can chill the drink faster than the unsplit cube. 

Now, let’s think about the total volume of ice in the glass, as that represents the amount of cooling power it has. A small piece of ice can only chill a beverage so much. More ice equals more chilling power, no matter if it’s shaped in one big cube or many small cubes. 

The total volume of ice determines its cooling power, while the surface area influences the rate of cooling. The big cube we cracked in half has the same amount of total cooling power as it did when it was whole, but it will cool faster when split into two. It will cool even faster if it’s split into smaller sizes.  

This ice is too big, this ice is too small

The shape with the lowest surface area-to-volume ratio is the sphere. A big sphere of ice will chill a drink more slowly than an equivalent amount of ice in another shape. 

Many people claim that an ice sphere in a glass of whiskey or other drink “cools the most with the least amount of dilution,” but that’s not true. It both cools and dilutes at a slow rate; those are linked. If you want a drink that chills with the least dilution, put a glass in the freezer for 10 minutes before you pour a drink into it. No ice means no dilution.

Still, big ice can be ideal for a drink like whiskey, where you don’t want it to get quite as cold as a cocktail. The ice will dilute and chill the drink slowly, which allows you to sip it over time. 

Often, dilution is just as important to the enjoyment of the drink as the chilling. If the whiskey is super high proof, like a barrel-strength scotch or bourbon, that water might bring it down to a more manageable sipping strength. A couple of small cubes placed in a glass of cask-strength bourbon can quickly dilute and chill it, and a big cube placed on top can maintain the temperature.

Sometimes you want a really cold drink with dilution, such as a Mint Julep. Crushed or shaved ice is the right tool for that job. When served in its traditional metal cup, all that ice cools your hands and provides ice-cold, minty water to sip for a few more minutes after the bourbon is gone. 

Which ice is just right?

So, what about regular ice cubes, the kind from your freezer tray or icemaker? Those are the most useful for the most drinks (if not being the prettiest ice, but that’s another story). They’re the ideal size to shake or stir cocktails, as well as for serving the majority of drinks. 

Big, two-inch cubes aren’t great to shake or stir. Often, they don’t fit into the shaker, and when they do, there’s not enough room to move around to mix and dilute efficiently. 

Ice that’s too small is also ineffective. In a cocktail shaker, soft, small ice (like pebble or nugget ice) doesn’t help much to mix ingredients or to smash up things like mint leaves, milk, and egg whites. 

In the glass, small ice covers the surface of a drink, and it can dampen the impact of carbonation. That may be why gas-station sodas with cracked ice taste better with a straw. Carbonated highballs, like a Gin & Tonic or a Vodka Soda, are ideal served over mid-sized ice, as they allow some of the bursting bubbles to tickle your nose as you sip. 

When cocktails are shaken, the ice breaks up inside the shaker. Most drink recipes specify to strain the drink over fresh, usually regular-sized ice cubes. 

The most common size of ice cube may be the most versatile option, but there are plenty of good reasons to work with other shapes to best control the temperature and dilution of your drink.