The Test weight concept was developed many years ago by the grain trade as a means of accounting for the varying densities of grain caused by weather and/or production practices. When grain density is lower than the accepted standard (low test weight), more volume is needed to store and transport a given weight of grain, thus increasing storage and transport costs. Different grades of each grain have different standard test weights. No. 2 yellow corn has a standard of 56 pounds per bushel while No. 3 yellow corn has a lower weight. Test weight is determined on each load of grain sold by weighing a known volume of the grain. If the weight is lower than the acceptable range, the sale is "docked" on a percentage basis. The seller of grain with test weight greater than the acceptable range is usually not rewarded for a superior product. Varieties of a crop often vary in their inherent test weight
http://ohioline.osu.edu/agf-fact/0503.html

Terme français : POIDS À L'HECTOLITRE
Définition française : POIDS SPÉCIFIQUE métrique, habituellement exprimé en kilogrammes par hectolitre; on convertit les livres par boisseau en kilogrammes par hectolitre en multipliant par 1.247 (Céréales et Oléagineux, IICG, 1984)
Terme anglais : hectolitre weight
Définition en anglais : METRIC TEST WEIGHT USUALLY IN KILOGRAMS PER HECTOLITRE; pounds per bushel can be converted to kilograms per hectolitre by multiplying by 1.247 (Grains and Oilseeds, CIGI, 1982)
http://www.grainscanada.gc.ca/glossary-lexique/ggtabc-abcltg...

English term: TEST WEIGHT
English subject field: grain technology
English abbreviation: TWT
English definition: weight of a specific volume of grain; bushel weight is the test weight, in pounds, of a bushel of grain; in metric measurements, it is the weight, in kilograms, of a hectolitre of grain; it is an important criterion in assessing the milling value of wheat; generally, the higher the test weight the greater the flour yield (Grains and Oilseeds, CIGI, 1982); weight of a measured volume of grain expressed in kilograms per hectolitre; for procedures, see chapter 1 of the Guide, Determining test weight (Official Grain Grading Guide); standard abbreviation
French term: poids spécifique; poids au boisseau
French subject field: technologie des céréales
French abbreviation: TWT
French definition: poids d'un volume spécifique de grain; le poids au boisseau est le poids en livres d'un boisseau de grain; dans les mesures métriques, c'est le poids en kilogrammes d'un hectolitre de grain; c'est un critère important d'évaluation de la valeur meunière d'un blé; en général, plus le poids est fort, plus le rendement en farine est élevé (Céréales et Oléagineux, IICG, 1984); poids d'un volume mesuré de grain exprimé en kilogrammes par hectolitre; voir la procédure au chapitre 1 du Guide, Détermination du poids spécifique (Guide officiel du classement des grains); abréviation standard
http://www.grainscanada.gc.ca/glossary-lexique/ggtabc-abcltg...

If you are SELLING YOUR GRAIN BY CONTRACT to a company in the United States, TEST WEIGHTS SPECIFIED IN THE CONTRACT are in pounds per bushel
http://www.grainscanada.gc.ca/guides-guides/weight-poids/itw...