Different design coffee roasting plant, different behaviours 😉 If you are recycling hot air and have the capability to change the point at which the recycle cycle is shut off (as in where you stop recycling and bring in only 100% ambient air instead) , try changing the recycle cut off point to a few different set points and see what happens & if that affects anything, significantly, marginally, or otherwise. My equipment is also very well insulated and enclosed nevertheless I am always making adjustments dependent on the prevailing weather, and have never really gone into the "why's", just the "arh harhs" of it all! Learn something new every day, especially with the very very different type of weather we've had this summer. which resulted in my making quite some changes to compensate for what I want in the roast. All good! This is the difference between having higher end 21st century equipment that can be "manipulated" according to the whims of the in house master of coffee, and old technology roasting plant where you cant do anything except vary inflow of gas to the burners and air flow through the flue. I expect those that are using old technology / budget type equipment with little control will have been having a very interesting summer, make no mistake.
