Protein content, ash percentage, and granulation determine whether a product is classified as flour, groats, meal, or pellets under the HTS. These distinctions affect both the applicable duty rate and admissibility documentation, so laboratory certificates of analysis are commonly required at entry.

Certain grain mill products sourced from specific origins have been subject to antidumping or countervailing duty orders in the past. Importers should check the USITC and Commerce Department databases for active orders covering the specific HTS subheading and country of origin before contracting a shipment.