This might get you going... I don't have your HW so you get to test it 
A lot of the variables are gone and things just depend on the currentState.
Also, I tweaked the LCD162 library to clean up a done of warnings (const char* to char*)
coffee_roaster.h (2.0 KB)
coffee_roaster.ino (17.4 KB)
LCD16x2.cpp (5.2 KB)
LCD16x2.h (1.6 KB)