Any aspiring bartender or cocktail connoisseur knows that presentation plays a huge part in making a great drink. When serving simple drinks, like a glass of straight whiskey, ice may be the only garnish one can add without affecting the whiskey itself. So will this ice sink or float?
Ice does not float in whiskey. This is because ice has a lower density than whiskey, which causes it to sink to the bottom of the glass. In a whiskey cocktail, ice may float slightly due to the mixture of water and alcohol, but it will not float in a glass of pure whiskey.
This article will further explore how density affects ice’s behavior in whiskey, alcohol in general, and other liquids and take a look at how best to use ice when making whiskey drinks at home.
Why Ice Doesn’t Float in Whiskey
While most of us probably learned about density at some point, it’s easy to forget that we see it in action almost every day. Density is a principle of matter and is used to essentially measure the heaviness of an object. It’s not the same thing as weight, however. UCLA Physics defines weight as the force of gravity on an object, whereas density is defined as mass per volume.
Are you still confused? It’s easier to think about these concepts with examples. Elmhurst College suggests thinking of two objects that are a similar size but made of different materials. Picture a tightly crumpled piece of paper and a rock of a similar size. We all know that the rock will be heavier.
You can also think of two cups, one made of styrofoam and one of ceramic. Even if they hold the same amount of liquid, we automatically know the ceramic cup will be heavier.
If we think of density as a measurement of how much is stuffed into a certain amount of space, it’s easier to understand. Let’s look at one more example. You can pack the same size suitcase with 3 sweaters or pack it to the brim with bricks. Even though the suitcase would be the same size, it would definitely be denser with the bricks. Pretty simple, right?
Density of Alcohol
So what is the density of whiskey, and how does that relate to ice sinking in it? Whiskey, like other popular spirits like vodka and gin, is a form of ethyl alcohol, also known as drinking alcohol or ethanol. Its density can vary slightly due to different distilling methods, but the National Library of Medicine puts it at 46.07 g/mol.
What does that mean to non-scientists? Basically, alcohol is pretty light. It’s actually lighter than water, which is why you will often see swirling patterns in whiskey cocktails that include water. The two liquids don’t mix easily because of their density, and eventually, the whiskey will float to the top. This short YouTube video shows this in action:
Density of Ice
Ice is relatively heavy when compared to alcohol, which is why it sinks to the bottom in a glass of whiskey. This is true, regardless of the shape of the ice. While fancy ice balls or ice slides used in cocktails may seem heavier than simple ice cubes, both will sink to the bottom in a glass of whiskey.
Why Ice Floats in Other Liquids
It makes sense to assume that because ice is heavier than alcohol, it would also be heavier than water and other liquids that are mostly water. Using common sense, we also know that cold things tend to be heavier than hot things. After all, hot air rises. Shouldn’t water increase in density as a cold, frozen solid?
Floating in Water
It turns out that the exact opposite is true due to the unique shape of water molecules in ice. When water freezes, molecules form into a lattice pattern instead of their random arrangement in liquid water. According to the US Geological Survey, this lattice pattern allows the water molecules to spread out, which results in ice being less dense than water. In fact, upon freezing, water is 9% less dense.
While you’ve probably seen ice floating in a glass of water countless times, the difference in density is even more dramatic when you think of icebergs. These giant ice chunks can be the size of small countries, according to the National Snow and Ice Data Center. And yet, because of their density, they still float in water.
Other Liquids
Since many of the most commonly consumed liquids are largely made up of water, ice floats in them as well. This includes:
- Milk
- Sodas
- Juices
- Smoothies
Using Ice With Whiskey
Whether or not to put ice in your whiskey is a topic of serious debate among whiskey aficionados. For many people just starting out with drinking whiskey, adding ice may be a good method to control the intensity of drinking the alcohol straight. As the ice melts, it will dilute the whiskey. Whiskey purists are unlikely to be okay with this, but it may be the best way to go for the casual whiskey drinker.
One thing all whiskey lovers can agree on, however, is that if you are using ice, you need to use the right kind. According to Whisky Advocate, small ice cubes are best for quickly getting your drink cold, while larger balls or squares are perfect for slow sippers. If you order a glass of whiskey at a restaurant or cocktail bar, they’ll probably use one of these larger options.
Tools for the Perfect Ice
If you are enjoying your whiskey at home, you will want to ensure you have the right tools to make the perfect addition to your whiskey.
- Ice balls: These ice spheres definitely add a touch of class to any glass of whiskey. This Glacio Large Sphere Ice Mold Tray lets you easily create them at home, with a silicone mold that makes it easy to pop the ice out when you are ready to make a drink.
- Ice slides: If you’d rather your drink have a more modern edge, consider using an ice slide. Amazon offers an Ice Cubist Cocktail Slide Set that comes with a mold for the ice slide and a whiskey glass.
Ice Alternatives
Want to keep your whiskey cold without diluting the great taste? Consider investing in whiskey stones as an ice alternative. Simply store these reusable cubes in your freezer and pull out when you are ready to make your drink. They come in a wide range of materials, but all function by holding the temperature of the freezer in order to chill your drink without adding water.
Amazon.com offers many different whiskey stone sets, including this Stainless Steel Whiskey Ice Cubes Set
and this Set of 9 Gray Beverage Chilling Stones made of natural soapstone. Whether you want the sophistication of stainless steel or the grit of soapstone, there’s a whiskey stone option that will work for you.
Conclusion
While it seems like ice arbitrarily chooses whether or not to float in different liquids, it’s all down to the simple physics principle of density. Density affects how ice behaves in every liquid it’s put in, from whiskey to water.
Aspiring bartenders should take note of how ice is denser than straight alcohol and sink in the glass. Investing in creative ice molds is a great way to add a fun element to cocktails and demonstrate physics in action.
Steve Rajeckas is an HVAC hobbyist with an avid interest in learning innovative ways to keep rooms, buildings, and everything else at the optimal temperature. When he’s not working on new posts for Temperature Master, he can be found reading books or exploring the outdoors.