Ice: the most important ingredient
Ice chills a drink by melting into it, so the water it adds is part of the recipe. Choose the right size, keep it cold and dry, and make it clear.
Why it works
Ice chills a drink almost entirely by melting. Turning 1 g of ice at 0 °C into 1 g of water at 0 °C absorbs 334 joules, about 80 times the energy needed to warm that gram of water by 1 °C. That is why a handful of cubes can take a stiff drink from room temperature to below zero in seconds. The cold surface of the ice does very little on its own. The chilling comes from the melt.
So chilling and dilution always arrive together, and you cannot have one without the other. That is a good thing. A Negroni at full strength is harsh, sweet and closed; with roughly a third more volume in water it opens up and the aromas lift. Recipes are written with that water in mind, so treat ice as an ingredient you measure by technique: how long you stir, how hard you shake, what size the cubes are.
Ice straight from a cold freezer, at around -18 °C, is dry and frosty. Warming it to 0 °C absorbs only about a tenth as much heat as melting it, so very cold ice chills a little better but its real advantage is that it carries no water on its surface. Ice that has sat in a bucket is wet: it is at 0 °C and coated in meltwater, and that water goes straight into your drink without chilling anything. Use the coldest, driest ice you have, and drain any that has been sitting out.
Size matters because ice melts at its surface. A 5 cm cube has half the surface per gram of a 2.5 cm cube, so it melts more slowly; crushed ice has many times more, so it chills and dilutes fast. A sphere has about 20% less surface than a cube of the same weight. Match the ice to the job: fast chilling and dilution in the shaker, slow and steady in a glass you will sip from for twenty minutes.
What you need
- Small insulated cooler: A hard-sided cooler of 4–8 litres that fits in your freezer with the lid off; this is how you make clear ice.
- Silicone ice trays: Trays for 2.5–3 cm cubes for shaking and stirring, and 5 cm cubes for rocks drinks; silicone releases ice without cracking it.
- Bread knife and wooden mallet: The serrated edge scores the block and a tap on the spine splits it; a rolling pin works in place of the mallet.
- Lewis bag: A thick canvas bag for crushing ice; the canvas soaks up meltwater so the crushed ice stays dry.
- Freezer bags or a lidded box: Keeps cut ice from picking up smells and from shrinking in the freezer.
- Metal ice scoop: Never scoop with a glass; a chipped glass leaves shards hidden in the ice.
Step by step
Fill the cooler
Fill the cooler with tap water to about 3 cm below the rim and put it in the freezer with the lid off. The insulated walls and base stop cold getting in from the sides and bottom, so the water freezes from the top down. As it freezes, dissolved air and minerals are pushed ahead of the ice front, into the water below.
Tip: Filtered water tastes cleaner but is not needed for clarity. Boiling the water does little; the direction of freezing is what makes clear ice.
Freeze for 18–24 hours
Leave it until there is a thick clear slab on top and a pocket of unfrozen or cloudy water at the bottom. In most home freezers that takes 18–24 hours for a small cooler. Check from the 18-hour mark; if you leave it too long, the cloudy water freezes and can crack the block as it expands.
Unmould and drain
Turn the cooler upside down over the sink and let it sit for a few minutes until the block slides out. Pour away any unfrozen water. If the bottom has frozen, you will see a white, cloudy layer; you will cut that off.
Temper the block
Leave the block on a towel or a board for 10–20 minutes, until the frosty white surface turns glassy and wet. Ice straight from the freezer is brittle and will shatter unpredictably when you strike it. Tempered ice at close to 0 °C splits cleanly along the line you score.
Tip: The same applies to single large cubes. Let them sit for a minute before they go into a drink.
Score and split
Saw a groove about 1 cm deep across the block with the bread knife where you want it to break. Set the blade in the groove and give the spine a firm tap with the mallet. Cut off the cloudy bottom first, then cut slabs, then cubes or spears.
Tip: Work on a damp towel so the block does not slide, and keep your free hand well away from the line of the cut.
Store it cold and sealed
Put the cut ice back in the freezer on a tray for 30 minutes so the surfaces refreeze and the pieces do not stick together. Then pack it into freezer bags or a lidded box. Ice left open soaks up freezer smells and slowly shrinks as it sublimates.
Crush ice when you need it
Put standard cubes in a Lewis bag, fold it closed and hit it with the mallet until the ice is the size you want: a few heavy blows for coarse cracked ice, many more for fine crushed ice. A clean tea towel works, though it soaks up less water. Crush just before serving, because crushed ice melts quickly.
Tip: For cracked ice to stir with, hold a cube in your palm and strike it with the back of a bar spoon; it breaks into three or four pieces.
Use plenty
Fill the shaker two-thirds to three-quarters with cubes, fill the mixing glass about three-quarters, and fill a serving glass to the top. Plan on about 1 kg of ice per guest for a cocktail evening, more in hot weather.
Tip: Shake or stir with fresh ice, then strain over fresh ice. Ice that has been shaken is broken and wet, and it will water the drink down in the glass.
Types of ice
| Ice | Size | Best for | Melt rate |
|---|
| Standard cubes | 2.5–3 cm | Shaking, stirring, spritzes and everyday serves | Medium |
| Large cube | 5 cm | Spirit-forward drinks on the rocks: Negroni, Old Fashioned, whisky | Slow |
| Sphere | 5–6 cm across | The same drinks as a large cube; looks elegant, about 20% less surface | Slowest |
| Collins spear | About 3 x 3 x 12 cm | Highballs and Collins: gin and tonic, Americano, Tom Collins | Slow |
| Cracked ice | 1–2 cm pieces | Faster stirring, frappés, short drinks served over ice | Fast |
| Crushed or pebble ice | Under 1 cm | Juleps, swizzles, cobblers, tiki drinks | Very fast |
Dilution and serving temperature
| Style | Water added | Temperature in the glass | Notes |
|---|
| Stirred, served up | 25–40% | About -1 to -4 °C | Silky and clear; stir 20–40 seconds with cold, dry cubes |
| Shaken, served up | 35–55% | About -5 to -7 °C | Colder and more diluted than stirred; aeration adds texture |
| On the rocks | About 20–25% when built, rising as you sip | About 0 to -2 °C | A large cube keeps later dilution slow |
| Highball | 5–10% at first | About 2–5 °C | Most of the volume is cold mixer; a full glass of ice keeps the fizz |
Troubleshooting
My ice is cloudy
Freezer trays freeze from every side at once, trapping air and minerals in the middle as a white core. Freeze in an insulated cooler with the lid off so the ice forms from the top down, and cut away the cloudy bottom. Cloudy ice chills just as well; it melts a little faster and looks less clean.
The cubes crack as soon as I pour the drink
This is thermal shock. Very cold ice warms and expands at the surface while the centre stays cold, and the strain splits it. Temper large cubes for a minute or two until the frost turns glassy, and set your freezer to around -18 °C rather than its coldest setting.
The ice tastes of the freezer
Ice absorbs smells from anything nearby, especially onions, fish and old food. Store it sealed in bags or a lidded box, keep it away from strong-smelling food, and use it within a couple of weeks. If the ice from your tray tastes off, wash the trays and check your water.
My drinks taste watery
Usually the ice was wet, there was too little of it, or the drink was stirred too long. Use ice straight from the freezer, fill the shaker and glass properly, and taste as you stir. Strain over fresh ice rather than tipping the shaker ice into the glass, and chill the glass first.
Crushed ice turns to slush before I can serve
Crushed ice has a huge surface, so it melts fast, and wet ice melts faster still. Crush in a Lewis bag so the canvas takes the water, crush just before building the drink, and pack the glass high so the ice sits as a cold mass.
My cooler block cracked in the freezer
It was left too long, so the trapped water at the bottom froze and expanded against the solid ice above. Take it out between 18 and 24 hours, or as soon as the clear layer is as thick as you need.
Ice, knives and glass
Ice straight from the freezer is brittle and shatters into sharp shards when struck. Temper it first and treat the knife with respect.
- Temper blocks and large cubes for 10–20 minutes before cutting.
- Cut on a damp towel so nothing slides, and keep your free hand behind the blade.
- Never scoop ice with a glass; if a glass breaks near the ice, throw all that ice away.
- Ice adds volume, not alcohol, so a long, well-iced drink is still a full serve. Drink with food and never before driving.
