In the world of specialty coffee, the term "small batch coffee roasting" is a significant distinction. The general premise is that smaller batch sizes allow for greater precision and control. To truly appreciate this approach, let's delve into the technical aspects that define smallb atch coffee roasting.
What is Small Batch Coffee Roasting?
As an industry standard, small-batch coffee roasting involves using a roaster with a capacity of 20 kilos or smaller. At a roaster capacity greater than this, the ability to hit a particular profile begins to narrow significantly. Thus the small batch roaster will have greater control of the roast process. Also, because of the difference in sheer mass, the small batch roaster will be able to increase the percentage of convective heat transfer relative to the two other types taking place during coffee roasting, conductive and radiant. How the percentages of these methods of heat transfer affect the flavor of coffee is a “rabbit hole” for another day.
Benefits of Small Batch Coffee Roasting
The potential advantage of small batch roasting lies in the heightened control over the roasting profile and process. An analogy that I first heard years ago during coffee roasting school at Mill City Roasters, is that roasting coffee is like steering a boat. The larger the boat the earlier and perhaps more significant the steering inputs needs to be in order to make the boat change direction and the slower that boat is to turn. So it is with coffee roasting, the larger the batch, especially relative to the capacity of the roaster, the more time it will take for the adjustments to affect the “direction” of the coffee roast.
The inferred lesson here is that smaller batch sizes are more controllable. Changes to gas and air inputs can affect the roast profiles in a much shorter amount of time and allow the roaster a greater amount of control over the coffee roast. Momentum is a term used often in coffee roasting. If you’re in a boat screaming across the water at a high rate of speed the more time it will take to slow that boat down. With coffee roasting momentum refers to the rate of heat transfer. The more heat you put into a roast early on may not show dramatically at that time. However when it’s time to reduce the rate of heat transfer that early “momentum” can make that difficult. And a large boat at speed will take quite a while to slow down while a small boat, or batch, can lose momentum more quickly.
How it Differs from Other Roasting Methods
Comparing small-batch roasting to its larger-scale counterparts reveals a trade-off between controllability and production capacity. While small batch roasting can offer meticulous control over complexity and nuance of the roasted coffee, facilities with larger roasters or even continuous flow roasters sacrifice control for increased production. At some point no matter the gas and air flow inputs, the larger roasters cannot match the roast profiles of the small batch roasters.
Why Choose Small Batch Coffee Roasting?
I’ve been reading about a conversation that’s happening between coffee growers, coffee buyers and coffee importers that suggests substituting the the word complexity for the word quality as a positive descriptor for coffee. I agree with this to the point that quality may be generally agreed upon within a group or an industry, however it is very subjective and difficult to convey outside of the group. However I observe complexity to be more measurable and more easily described. This implies that complexity is a desirable trait in coffee, with which I agree. So a small batch roaster with greater controllability would be able to reveal the complexities of specialty coffees to a greater degree, even potentially being able to modulate the flavor profiles.
As we navigate the complexities of small-batch coffee roasting, it becomes evident that this method is not just about quantity – it's about an intimate understanding of the beans, a commitment to complexity, and a tool within the artistry of roasting. In the next blogs, we'll further explore the history, benefits, challenges, and future of small-batch coffee roasting. Stay tuned!