I am a human. I need coffee. I also need to not drink hot beverages on 90 degree days. Dilemma. Of course, you could drink iced coffee, but our ice machine isn't working...and it's either too concentrated or too diluted... or, hell... it's just too boring.
This is my verion of hot-weather caffeine, a cross between a Coke and a Cappuccino -- a nice mug of cold, fizzy black coffee. No milk or sugar please. I find that seltzer always tastes a little bitter to me. This just furthers that, with a front nose of coffee, a bitter bubble, then a crisp finish that brings to the fore coffee's lighter flavors -- not nuts and tobacco, but more delicate notes of citrus.
Carbonated coffee would be killer with a scoop of chocolate ice cream. Like a Rockwellian soda fountain treat trying to be an affogatto. Delightful.
Recipe: Make 1 liter of coffee as you like it. Refrigerate until cold. Carbonate in your Sodastream or other soda maker. Your Sodastream will not like this. I think it's the oils in the coffee that emulsify with the air. The fizz will be formidable, so just unscrew the bottle in the sink. It is a machine and you are a human, so make it do your bidding.