Pre-blending before roasting. Pre-blending is combining different coffee components into one batch when the beans are green, then roasting the pre-blended beans together simultaneously. The most important advantage of pre-blending is guarantee of consistent batch size, which creates consistency in roast. The main challenge of blending before roasting is a lowered level of refinement.
Post-blending after roasting. Post-blending is about roasting each component as a separate batch, then mixing the roasted beans to create a blend. Post-blending considers more control over the roasting process of each bean type, so you can calibrate the roast level. It also allows more diverse roasting combinations like a blend of light-roast and dark-roast beans. Post-blending is a best choice if you know you’ll have varying batch sizes for each type of coffee.
Split roasting. This technique involves separating coffee beans into different sections based on density or size, not origin. After roasting each section separately, blend all the roasted beans. It requires a skilled master. By roasting each density or size as a separate batch, beans can roast evenly to develop full roasting potential.