Wheat starch paste: a study of cooking profiles and adhesive properties across preparation recipes.

Wheat starch paste (WSP) is an adhesive commonly used in the field of book and paper conservation. Each conservation studio must regularly prepare WSP in small batches because of its very short shelf life. Over time this has led to the development of a corpus of ad-hoc recipes and sometimes contradictory practices. This article attempts to rationally analyse WSP preparation and to identify what parameters may affect the quality of the end-product for conservation use. After collecting over 50 recipes from publications and conservation professionals, a set of eight parameters were identified: starch source, pre-soaking, starch-to-water ratio, cooking method, cooking duration, cooking temperature, sieving and storage time/method. A set of 72 cooking experiments were then conducted varying each of these parameters in turn. The findings presented here are intended to provide a set of practical guidelines to help conservators optimise their paste-making processes and identify which practices and parameters had no measurable effect on paste quality and, conversely, which ones did; and for the latter, to provide a well-defined range of values for the production of a very homogeneous quality product, suitable for conservation work. It is important to stress that this research has only scratched the surface of conservation WSP quality analysis, leaving many areas open to further study. [ABSTRACT FROM AUTHOR]