| Roaster Guide: Why Is Green Bean Moisture Content Important? - Perfect Daily Grind
Of equal concern is #UnderDrying . Like with under-drying, over-drying can have profound effects on cost. The farmers will have to pack more beans into each sack in order to make up for the loss in weight. Therefore, in larger plantations, the farmer may lose an entire sack's worth of coffee from poor drying methods. As moisture can be lost during transit, farmers may over-pack the sacks anyway. This is both a courteous gesture and done to help procure the sale of more sacks in the future.
Over-drying also affects the quality and taste of coffee. At 9% moisture, you can expect a loss in aroma, freshness, and clarity. If the moisture content drops below 8%, then the roasted bean would contain hardly any flavour at all. As we said above, coffee below 8% should not be shipped.
Moisture content is also crucial when the coffee is being roasted. Since water conducts heat, the moisture in the bean provides a pathway for the heat to transfer to the centre of the bean. With too little moisture, the beans roast too quickly on the outside and the inner is left raw creating grassy flavours.
The temperature of the roaster can be adjusted. However, a slow roasting process can draw out baked flavours. This is equally undesirable.