Wood ash tempering in archaeological ceramics: an experimental approach for its characterisation using textural, chemical, and mineralogical analysis

Abstract

This paper establishes criteria for identifying wood ash tempering in archaeological ceramics, a practice documented ethnographically across the globe but likely often unrecognised in archaeological studies due to the lack of established diagnostic markers. Through an experimental project employing a multi-analytical approach, this study identifies key indicators of ash tempering, highlighting the utility of thin section petrography for low-fired ceramics and X-ray diffraction (XRD) analysis for high-fired ceramics as particularly effective techniques. Finally, we present two archaeological case studies in which the application of our findings has enabled the identification of likely wood ash tempering.

Recognising this practice is essential, as its absence in archaeological interpretations may result in missed opportunities to understand past craftspeople and technological traditions. Furthermore, the identification of wood ash tempering offers insights into cross-craft interactions and the potential application of circular economic principles, given the frequent use of waste ashes from other industries in ethnographic examples. By refining methods to detect ash tempering, this research contributes to broader discussions on sustainability, resource reuse, and technological innovation in the past.