The quality of wheat (Triticum aestivum L.) is end result of the expression of many genes that are modulated by the environment. The physiology of wheat quality can be understood by examining the environmental effects on the gene products that most influence flour quality. For simplicity, this presentation will examine the expression of two contrasting systems: the relatively simple puroindolines that determine grain hardness and the more complex genetic systems that produce gluten, a matrix of different protein classes, lipids and minerals that provides the network for dough development in during food preparation. Puroindolines are encoded by a single complex locus on chromosome 5DS. Functional forms of the 5DS genes confer a soft endosperm kernel with low energies to mill flour that typically has small particle sizes and low water absorptions. Loss of function in one or more of the tandemly repeated puroindoline genes results in hard kernels that require greater energy to mill and produce a much higher water absorption flour than flour milled from soft kernel. Environmental influences, particularly moisture stress, can modulate kernel hardness yet a majority of the variation in kernel hardness can be assigned to genetics rather than environment. In contrast to the puroindolines, gluten is coded by at least 6 complex loci that are strongly influenced by environment. Soil nitrogen, moisture availability, and air temperature during grain-fill are a few of the known environmental causes of gluten variation. This presentation will pose necessary questions to improve our understanding of both grain hardness and gluten.