ASAE Standards for Moisture Determination

ASAE Standard S358.2 (DEC93) - Moisture Measurement - Forages

This standard describes the procedure for estimating the moisture content of forage materials in various forms. A representative sample of at least 25g is selected. It is not necessary to chop or grind the sample unless it has been previously compacted (i.e. cubes and wafers). If grinding is necessary, the ground particles should be less than 15 mm. The sample is placed in the sample container. An aluminum dish is preferred but containers made from other non-hygroscopic materials may also be used. The samples are placed in a convection oven and dried. If the sample is for moisture determination only, it can be dried at 103°C for 24 hours. If the sample is to be used for further chemical analysis, dry it at 60°C for 72 hours. This lower temperature reduces the chance that organic acids may be driven off during heating.

Note: Some scientists contend that drying at 103°C drives off volatiles other than water and that 103°C should not be used under any circumstances.