It doesn't matter what you're drinking. If there's ice in your glass, it's holding all the power. Those little frozen cubes (or shards, or shavings) can make the difference between a perfectly chilled, flavorful cocktail and a watery waste of good liquor. Once you've chosen your spirits and picked out a recipe, it's time to reconsider your rocks.
The rise of the mixologist in recent years has ushered in a new era of hand-carved ice, glass-sized cylinders engineered to cool and dilute drinks at the perfect rate. But you don't have to be a full-on frozen water enthusiast to get your hands on the right cubes -- with just a few tips, you too can stop bad ice from ruining great cocktails.
Consider the cocktail (or spirit). The purpose of the ice in the drink will determine the best sort to use. If you're enjoying a spirit straight, and your goal is to enjoy the liquor in all of its purity, you'll want to choose cubes that offer limited surface area -- a few large, hard frozen, uniform blocks as opposed to a glassfull of oddly-shaped smaller ones -- to ensure that you can finish the drink before the ice has melted. Scotch or other dark spirit drinkers (or anyone else looking for a cold drink with no dilution) can opt out of ice altogether, and select whiskey stones instead.
Colder is better. Conversations about ice are often eye-roll-inducing, typically because of comments like this one. But it's true: adding wet, already-melting ice to your drink is essentially like adding water right away. If you've mixed a perfect cocktail and want to keep it as is, don't add ice that's already halfway back to liquid. For cocktail parties at home, keep your ice in the freezer as long as possible, not in an icebucket at the bar.
Keep it fresh. Believe it or not, ice gets old in a hurry. It may stay frozen for months on end, but after just a few weeks in the freezer, it picks up the flavors and aromas of anything nearby. Protect your drink from tasting like salmon filets or even just like the freezer itself by replacing your cubes on a regular basis.
Know Your Ice Types.
Cracked -- Great for mixed drinks that need a fast chill and good stir. Crack larger ice cubes by tapping them on a hard surface with a spoon.
Crushed -- Appropriate for mojitos and mint juleps, crushed ice is great for when dilution is a desireable result -- a little melt-off helps soften very strong flavors. To crush ice at home without a blender or ice-o-matic, place cubes in a plastic bag, wrap it in a towel, and tap with a hammer until you're left with shards.
Cubed -- Look for cocktail-specific ice trays that make ice cubes into, well, actual cubes; the larger the better. Achieve clearer pieces by using hot filtered water at the outset. For larger cubes to use for Scotch or other spirits, freeze water in small Picardie tumblers or jelly glasses, running hot water over the outside of the glass once frozen to release the large cylinder of ice.