During a crude fiber or acid detergent procedure, the time frame during which samples are exposed to 100°C solution(s) is extremely important. If the fiber analyzer begins a procedure at a temperature higher than 20°C, the instrument will heat the solution too quickly and the effective digestion time frame will be too long. This will create lower than expected fiber values. As a result, when performing back-to-back fiber runs with the second being a crude fiber or acid detergent procedure, we would suggest pouring cold water into the vessel prior to the second run in order to cool the instrument to room temperature.