The experimental heating of rye, oat, spelt, wheat and barley between 215 and 300 °C: the stable carbon and nitrogen isotope data and the photographic evidence of changes to the morphology of the grains.

ABSTRACT

The effect that heating has on cereal grain morphology and isotopic values has far reaching consequences for archaeobotanical research and palaeodietary reconstructions. Stable carbon and nitrogen isotopic data and mass loss percentages on, and photographs of, rye, oat, barley, wheat and spelt from a heating experiment are presented and support Stroud et al. (2023). The experiment heated rye, oat, and spelt at 215 °C, 230 °C, 245 °C, 260 °C and 300 °C for 4 h, 8h and 24 h, with each temperature/duration condition consisting of 3 samples of 10 grains per sample. The mass loss of the grains, the %C and %N, and δ13C and δ15N values are presented. Furthermore, photographs of the grains' external and internal morphology for each temperature/duration combination are provided. The wheat and barley data of samples charred between 215 °C and 260 °C/ 4-24 h were obtained from the published and unpublished dataset of Nitsch et al. (2015) and it is this dataset which the new data builds upon. This article also provides the published and unpublished data and photographs from Nitsch et al. (2015), bringing together a dataset of nine crop species. This article provides the raw data from two cereal grain heating experiment, which will enable further research into understanding the impact of heating on both grain isotopic values and grain morphology. It also allows users to construct charred-uncharred isotopic offsets for a combination of species relevant to their research.