If you're interested in whipping up a batch of coffee kombucha yourself, here's a quick and easy recipe to start with. Making coffee kombucha is no more labor-intensive than making regular kombucha with tea, but there are a few pitfalls you need to be aware of.
In a non-porous container—glass or ceramic is a good choice—combine 2 quarts of freshly-brewed hot coffee with ½ cup of sugar. Stir until the sugar dissolves and let the mixture cool to room temperature.
Add the SCOBY and cover the container with a coffee filter or cloth. Make sure the container is tightly sealed by securing the cover with a rubber band.
Leave the mixture at room temperature out of direct sunlight for at least 7 days. Be sure to monitor the kombucha for signs of rancidity daily.
After 7 days, taste small amounts of the kombucha through a straw once per day until you reach your desired taste.
Notes
If you're unfamiliar with the term SCOBY, it is an abbreviation for "symbiotic culture of bacteria and yeast" used for making fermented drinks. Coffee is more acidic than tea and contains natural oils from the coffee bean. Both of those factors combine to increase the chance of coffee kombucha spoiling during the fermentation process. It is imperative that you carefully check your coffee kombucha for signs of rancidity before you consume it. If the kombucha has a funny smell or look, discard the entire batch and try again.