Moisture content (or level) is the percentage of water present in the coffee, which tells you how well the coffee was dried. Our acceptable range of moisture content in coffee is 9.0-11.5%. Any higher and the risk of mould or other fungal infections is high. Any lower and the coffee will lose flavour quickly, and show signs of early ageing.
A sudden change in moisture content can be a sign of bad storage or ageing. When the moisture percentage rises it is usually due to high moisture levels in the air of the storage space, and mould or fungus can infest the green coffee. The ideal storage facility has a stable temperature of 18-20 degrees celsius, and stable humidity of 40-50%.
A moisture meter for measuring moisture content