Think of the ingredients you need to make a great cocktail and your mind probably turns to spirits, mixers and fruit. But one vital ingredient often gets overlooked. Nonetheless, it's one of the most important components of a cocktail. That ingredient is ice. And it can make or break a cocktail.

Before the beginning of the 19th century, ice was not a common ingredient in alcoholic drinks – it was an expensive luxury, and most was reserved for food preservation. Frederic Tudor (aka the Boston Ice King) had the idea of selling and distributing ice to bars in order to give patrons cool drinks. Business quickly boomed.

A couple of hundred years later and good ice is so important in the making of cocktails that many bars have installed ice machines to ensure they are using the best ice.

At The Roosevelt, they have two ice-making machines to create the ice for their award-winning cocktails. Bartender Phil Gandevia explains that good ice “is now back in fashion”.

“It has come from places like Japan, where high-quality ice has always been important in cocktail making.” Use bad ice, he says “and you'll taste impurities in the ice and you'll get a more diluted cocktail, both of which will upset the flavour of your drink.”

So how can you make good ice at home without a fancy machine? Firstly, get a clean plastic takeaway food container. Get water from your cold tap and then boil it (the more times you boil it, the purer it will be). Let it cool, pour the water into the container and put in the freezer. When it's ready, remove it from the freezer and let it sit for 10 minutes. Using a cheap meat cleaver, saw back and forth through the ice. When you're about one-third of the way down, get a screwdriver or chisel to break the ice into blocks. Repeat until you've got six pieces from your one block.

You can do other things with your large block of ice, like splitting it into thin spears for use in highball glasses. Or you can the put cubes into a zip-lock plastic bag and pound them with a mallet to get crushed ice for drinks like mojitos.

You can also experiment. Silicon baking trays and cake moulds are a great for interesting shapes. You can also get really creative and make flavoured ice – ideal for punches – or freeze herbs or flowers for use in your own homemade cocktails.

Flick through the gallery above and watch how it’s done.