Category: Lab Best Practice

Even the best laboratory equipment produces unreliable results if the testing procedure is flawed. After years of working with flour and grain laboratories, we have seen the same errors appear repeatedly — often in facilities that consider themselves well-equipped. Here are the five most common testing mistakes and the practical steps to eliminate them. 1. Inconsistent Sample Conditioning Most flour laboratory tests are highly sensitive to moisture content. Failing to condition samples to a standard moisture level (typically 14% for wheat flour) before testing introduces systematic variability. Always use a conditioning chamber and allow adequate equilibration time — a minimum of 2 hours, preferably overnight for cold samples arriving from storage. 2. Skipping Instrument Warm-Up Electronic laboratory instruments — particularly NIR analysers and Falling Number units — require warm-up periods for their heating elements, electronics, and optics to stabilise. Running tests immediately after switching on the instrument is a common source of outlier results. Follow manufacturer warm-up specifications religiously. 3. Neglecting Reference Sample Checks Running certified reference materials at the start of each testing session is the only reliable way to verify that an instrument is performing within specification. Many laboratories skip this step to save time — and then spend far more time investigating unexpected results. A simple daily check with one certified reference takes less than five minutes and protects every result that follows. 4. Poorly Maintained Sieves and Consumables For gluten washing and sedimentation tests, damaged or clogged sieves are a frequent source of error. Sieves should be inspected regularly under magnification, replaced on a scheduled basis, and never cleaned with abrasive materials. Similarly, Falling Number viscometer tubes should be inspected for scratches, which alter fluid dynamics and introduce measurement bias. 5. Inadequate Sample Homogeneity A 10-gram sub-sample for a Falling Number test must be truly representative of the lot being assessed. Failing to properly mix and split bulk samples before sub-sampling is one of the most common root causes of between-laboratory discrepancies. Use a rotary divider or riffle splitter to ensure representative sub-samples, particularly for heterogeneous grain lots with potential sprouting pockets.