My recipe for a coffee mead that comes out at about 14%. High alcohol and high caffeine content are always a good mix.
For me it took about 10 weeks to ferment out, and took another good 2-3 months before it lost its jet fuel tang. Completely rank when I first bottled it but it slowly became really pleasant. Probably more of a winter drink than a summer one.
Yields 5l (1 UK gallon).
(slightly less than) 5l of cold brew coffee
Leave a 1:4 ground coffee to water mixture overight. The next day, strain it through some cheesecloth into a demijohn. I used Columbian but I think any low-acidity coffee will work…
1.3kg of honey
I used a general wine yeast but the fermentation stalled about half way. I added some EC-1118 champagne yeast which got it going again and fermented it to completion - so use that (or something similar)
Note on gravity measurements
The gravity of the unfermented mead will be offset by the gravity of the coffee. For example my coffee had a gravity of 1.010 so I when I was checking the progress of the fermentation I was referencing the gravity of the coffee as the point at which the mead would be dry (which is usually 1.000)
This is assuming there’s no fermentable stuff in the coffee itself which could be totally wrong but it seemed to work out for me.