To roast coffee, you need to burn gas.
Burning gas emits a lot of carbon. And it’s expensive. But not all roasters are created equal in terms of their gas efficiency. We had this in mind when we first acquired our Loring Peregrine S70 and S7 Nighthawk.
We wanted to compare the energy efficiency per kilo between our Probat P25 and the Loring S70. We knew that the Loring would be more energy efficient, but we weren’t sure exactly by how much.
Here are some calculations from our warehouse, based on gas usage measurements during roasting from the gas meter. These calculations are based upon the energy required to roast 1kg of coffee*. Both roasters are powered by natural gas.
NOTE: calculations based upon a full batch size (70kg in Loring and 21kg in the Probat P25). Carbon emissions are based off the combustion of natural gas only–emissions resulting from electricity usage are not included in the calculation.
Loring S70 Peregrine
• 2.3MJ/kg
= 138g of CO2 emitted per kilo
Probat P25 + Afterburner
• 10MJ/kg
= 600g of CO2 emitted per kilo
There you have it. The Loring S70 is over four times more efficient than our P25. It’s not a truly fair experiment as some efficiency is achieved at scale (i.e. if we were comparing to 70kg roasters). However, it’s worth mentioning that the P25 uses 30% more gas in absolute terms than the S70! Check this out:
Total MJ required for a single roast:
Loring S70 Peregrine
• 162.381MJ per roast
= 9.72kg CO2 emitted per roast
Probat P25 + Afterburner
• 212.641MJ per roast
= 12.758kg CO2 emitted per roast
In other words, the Probat P25 uses 30% more gas to roast only 30% of the coffee that can be roasted by the Loring S70.
We were stoked to see how remarkably efficient the Loring is. A future goal is to replace our entire ‘fleet’ with Loring roasters. As a co-roasting facility concerned with sustainability issues, we believe this is a significant step in the right direction.
