A lot of people think I am crazy when I tell them that ice is the most important ingredient in a cocktail. They challenge me by asking, “what about the booze?” But the truth is that without great-quality ice, you can never have an incredible cocktail. Having large chunks of double-frozen ice decreases the surface area of the ice that is touching the liquid and therefore slows down the dilution process, keeping your drink colder and more flavourful for longer. Most bars with beautiful icebergs in their cocktails buy their ice commercially, but there is a little trick that you can even do at home. Take your Thermos cool box and fill it with water. Place it in your freezer and wait. The insulation of the box slows down the freezing process, allowing the air and minerals to rise to the top. Simply remove this top layer and, hey presto, you have professional-quality blocks of ice.