Quality assessments made in leaf threshing factories have a dramatic impact on the usability of these products by tobacco manufacturers. Historically, there have been no common definitions and methodologies used in measuring stemmery quality. The CORESTA Task Force on particle size sieve analysis and stem content presented draft proposals to the CORESTA Scientific Commission which were accepted during the Octobre 1990 CORESTA conference in Greece. The result of this work establishes a format for international standardization of stemmery quality assurance procedures.