This article analyses how gluten was discussed by chemists in the nineteenth century in Great Britain and France as a proxy for both nutritive and baking quality. It examines the role of gluten in the broader quest to measure and render the quality of wheat and flour through a set of objective and quantifiable criteria. The paper also shows how measuring quality proved to be an extremely complex task, and how chemistry was, by itself, unable to reduce the complexity of the wheat grain, and the various demands made upon it, to a simple numerical indicator.