Roasting coffee is a complex chemical process. Comparing that process from one roaster to another is difficult for a number of reasons.
● Each lot of coffee is different. Even if you have coffee from the same farm as another roaster, it is likely to be a different batch.
● Ambient conditions also come into play. Roasting environment temperature, humidity, temperature of the green going in all effect the roast.
● Voltage varies greatly and individual roasters behave slightly different as well.