Cold Brewed Iced Coffee
I'm relatively new to coffee drinking, but have graduated from instant to actual brewed liquid energy. I was intrigued when I read about cold brewing and how it can make a smoother beverage with more kick. So I gave it a try and I am a convert. Any leftovers can be stored in the fridge, or made into ice cubes.
You don't have to add more water to your drink, but remember that this coffee concentrate is quite potent in terms of caffeine kick, so you may want to water it down a bit.