Assessing natural variation and the effects of charring, burial and pre-treatment on the stable carbon and nitrogen isotope values of archaeobotanical cereals and pulses

► We examine levels of isotopic variation within modern cereal and pulse crop species. ► We examine the effects of a charring on the carbon and nitrogen isotope values of cereal and pulses. ► We examine the effects of the ABA pre-treatment method on the δ13C and δ15N values of cereals. ► Charring has negligible effect on δ13C values but can increase δ15N values approximately 1‰. ► δ13C and δ15N values of charred ancient crops can provide valuable palaeodietary information.