There is much discussion and consternation about the temperature of the lever group and its relation to shot temperature on the pull. Group temperature is notoriously fussy on the saturated groups such as Olympia Cremina and La Pavoni machines (the manual levers) but even the large commercial spring piston groups can "heat up" on consecutive shots and require some user thought and monitoring to maintain proper temperature balance.
The optimal group temperature for pulling a shot of course depends on many user centric variables, such as coffee used, ambient temperature, number of shots in succession, type of machine, and frankly, the list goes on and on. And yes, there are differing schools of thought on the subject as well so nothing is etched in stone and there is no magic formula since as in many cases, "your mileage may vary".
These thermo indicating temperature strips can help one gain some factoids of information on the generally analog lever group and give one feeling of control preparing to pull a shot. The pair of strips in tandem can also help you generate your own data set to enable a better degree of repeatability for some desired extraction parameter. One glance and you know that it is time to do a bit of thinking before pulling that shot!
We carry this temperature strip in 2 ranges:
60 - 90 Centrigrade
Or, the pair to cover from 60-120 Centigrade!