All about coffee by William H. Ukers

5. _Moisture--Tentative_

Dry 5 grams of the sample at 105°--110°C. for 5 hours and subsequent periods of an hour each until constant weight is obtained. The same procedure may be used, drying _in vacuo_ at the temperature of boiling water. In the case of whole coffee, grind rapidly to a coarse powder and weigh at once portions for the determination without sifting and without unnecessary exposure to the air.