Mechanical properties and structure of bread crumb are important factors in bread quality evaluation. The objective of this study was to determine the relationship between crumb texture and crumb grain, as affected by flour type and proof time. Bread was prepared using a short time process using four spring wheat flours of varying strength. Proof time was varied (optimum, -40%, -25%, and +40%) to manipulate crumb grain. For two of the flours (CWRS and CWES), the effects of varying water absorption (60-65%) were also assessed. After density measurement, crumb grain was measured by digital image analysis (DIA). Tensile tests were performed on dumbbell shaped specimens cut from the same bread slices used for DIA. Crumb density, grain, and texture were significantly affected by flour type and proof time. Absorption significantly affected crumb texture only. Young's modulus was most closely related to crumb grain based on a linear regression model comprising crumb void fraction and cell wall thickness; depending on flour type, the R2 ranged from 0.6 to 0.8. Strength and energy to failure were dependent on flour type (i.e. dough strength) only. It was concluded that mechanical properties of bread crumb are strongly influenced by crumb structure. The protein quality of wheat, by its influence on dough strength, also appears to be an important underlying factor affecting the tensile strength of bread crumb.