Ice is an essential part of the cocktail. the type of dilution it provides can substantially impact on the quality of your cocktail.
Ice does two things to a cocktail: cools it & dilutes it
LARGE ICE CUBES
If you’ve been to a cocktail bar in the last five years, you’ve probably seen those giant ice cubes that fill up most of the glass. Serving a spirit-forward drink over those large rocks will add less water to your drink, over time.
With big ice, that drink temperature and dilution are going to stay consistent for a pretty extended period of time. If you have a really nice whiskey or a really nice bourbon, you want to serve it over a big rock, because then you have a long time to finish it before turning your drink watery.
Serve spirit-forward drinks such as the old fashioned over big ice. Ice spheres (big circular ice balls) have no edges, which yields even less condensation.
Some drinks benefit from a big old pile of crushed ice, especially those that are designed to be served in warmer climates or use a lot of fancy syrups and juices. Because the tiny pebbles will thin out syrups and juices, they work well for those types of drinks — call it the snow cone effect. If you’re whipping up a refreshing Mint Julep, a boozy tiki, or Rum Swizzle, you’ll want crushed or pebble ice. That will add just the right amount of dilution to these spirit-forward cocktails, while keeping them consistently chilled.
The most important consideration with crushed ice is how much water it gives off. Since it’s made up of a lot of small pieces, crushed ice can get watery very quickly, and that could dilute your drink faster than you want. Note that cloudy ice shatters more easily, so if you’re working with standard freezer ice, be aware of that.
For home bartenders, a Lewis bag and a wooden mallet (see video above) will give you a fun way to work out any mid-party aggression, while the bag absorbs any excess water.
STANDARD ICE CUBES
Standard, one-inch-by-one-inch cubes are the workhorse of the ice world. They are great in pretty much every cocktail, and if you use cubes that are all about the same size, they’ll also melt consistently. Believe it or not, ice does have a shelf life — about two weeks, depending on what else you have in your freezer.
If you don’t use your ice very often, store it in a plastic bag, because your ice will start to pick up ambient flavors from your freezer. You’ll pour a little Japanese whiskey over an ice cube and go, ‘This tastes like frozen pizza.’
Most people can get away with freezing water right from the tap, but use this rule of thumb: If you wouldn’t drink your tap water, don’t use it to make ice. The main issue home bartenders run into with standard cubes, according to bartenders, is not having enough. you always need more ice than you think you do. You do need to fill the entire shaker with ice, and then move your ingredients around through that.