Ice is one of the most overlooked and important factors in how drinks taste. You can never have too much, though the public see it as a way of bars saving money and ripping them off, when it couldn’t be further from the truth!
The Science of Ice
The more ice in a drink, the LESS watery it will taste. While this sounds counter intuitive, when you think about the physics of it, it really makes sense.
Ice cools the drink buy absorbing the heat in the liquid, which raises the temperature of the ice. If half of the content of your glass is ice at -5 and the rest is liquid at +7, all your ice will melt to water. So the colder your ice is to begin with, the better, and higher proportions of ice is better!
Also when you fill a glass with ice, the ice sits in contact with other ice, keeping both cooler for longer. Any drink that you serve on the rocks should end up empty before the ice is all gone!
When you fill a glass with ice, yes, there is less space to fill with liquid, and this makes drinks taste better – bartenders are not going to add more liquor to a drink because you ask for less, you might get extra mixer though, and your drink will taste weaker – the ideal ratio in general for a spirit and mixer is 1:3, but with less ice the drink will have more mix at the start, and be a watery mess by the end!
While cubes are by far the most common way you’ll find your frozen water, crushed ice is very popular in modern drinks from the Mojito to the Russian Spring Punch, and sits even tighter together in the glass, rapidly chilling the drink. On the downside, the smaller pieces will melt more quickly when not enough is used to really chill the drink in the first place.
At the other end of the spectrum is the whiskey ball – large balls (about 2″)of ice generally made in silicon moulds which have a large mass of ice in a single block. These melt very slowly and therefore limit the amount of water being added to a drink.
Whiskey stones are another option, particularly for drinking expensive malt whiskeys or other premium spirits that you want cold but with zero dilution. They’re solid stones which are kept in the freezer and then added to a drink to chill it without any water involved.
Camper English over at Alcademics writes extensively about craft ice and its use in cocktails, you should check out his awesome work!