What can I say? It’s actually really nice. Cold brewing works, the coffee is tasty and slightly less bitter than hot-brewed; it’s damn refreshing on a hot day and it miles healthier than any iced concoction bought from Starbucks or Costa – probably a minuscule fraction of comparable sugar content and negligibly calorific in comparison.
It’s not, however, a new hipster thing: cold brewing comes from 17th century Japan and, as you might expect, was an elaborate, tortuous (drop by drop) process. But by all means you can just mix ground coffee with filtered water and set it on the kitchen worktop overnight.
The filtering of the liquid is the key element, of course: you want the resulting liquid to be lovely crystal clear. Standard coffee filters work well though you might need two, stuck together or in a filtering succession. If you have a fine mesh tea strainer, you can use that. Or a cheesecloth over a sieve. Or a silk hankie.
The caffeine content is allegedly higher in cold brew than regular coffee, be aware. I am so caffeine-immune that I nod off over a double espresso, thus not the right judge of that. It is tasty diluted anyway, with condensed milk over ice cubes for best experience.