Crisp bread (rye)

Rye naturally supports the growth of lactic acid bacteria, which is great for sourdough flavor but also means more histamine potential.

• Rye fermentation — most rye crispbreads use some form of fermentation or sourdough starter, which builds histamine as part of the process that gives rye its characteristic tang

• Concentration effect — because crispbread is dried down to a dense, shelf-stable product, whatever histamine developed during production is present in a more concentrated form than in soft bread

Plain rye crispbreads with minimal added ingredients tend to be the more predictable option.