Roast profiles rely on consistency. To perfectly replicate a roast, all variables need to be controlled and matched to the original reference profile. This includes your batch size.
If you use a 10lb roast profile to roast a 6lb batch, you will need to steer your roast differently. At Mill City's Roastery, the majority of our roasting is done on two 20-kilogram roasters. We have set batch sizes to maintain consistency. This gives us the flexibility to scale up or down based on what our customers order while maintaining flavor consistency for each coffee.
We’ve calculated our standard batch sizes to produce specific amounts of roasted coffee, or output. Because most of our roasting program is wholesale, and the coffee is packaged in five-pound bags, our batch sizes are always in increments of five. This helps us eliminate waste and ensures we don’t end up with odd amounts of extra coffee.
Here are our standard batch sizes:
| Batch Size | Greens Weight | Roasted Weight (approx.) |
| Full Batch | 42lb | 35lb |
| Medium Batch | 30lb |
25lb |
| Small Batch | 18lb | 15lb |
Each of these standardized batch sizes has a set charge temperature and initial fuel setting, making it easy to plan for the roast. If you are a newer roaster, this is a helpful approach. When you bring in new or unfamiliar coffees into your space, you will use similar charge temperature or gas pressure in relation to your batch sizes.
Consistent batch sizes are vital for roast profile accuracy and flavor consistency. Standardizing these streamlines your processes, reduces waste, and ensures predictable roasting.
