Things I do for coffee (A.K.A., fun with thermodynamics)

I needed hot water at around 80-85 Celsius to use withnAeroPress.nAt the time, I didn’t have a thermometer that goes higher than 50C.nI know the room temperature and the temperature of near-boiling water (close to 100C ).nThe result: a calculator, for a cool (pun intended), practical use of thermodynamics.