Andaliman is the dried (or fresh) berry of Zanthoxylum acanthopodium, a thorny prickly-ash of the Sumatran highlands and the signature spice of the Batak peoples of North Sumatra. Like its cousins Sichuan pepper, Japanese sanshō and Nepali timur it is neither a true pepper nor a chilli but a member of the citrus family, and it delivers the same buzzing, tongue-tingling numbness. What sets andaliman apart is its aroma: an unusually vivid, almost perfumed burst of lime, grapefruit and lemongrass that Batak cooks prize above the numbing itself — the soul of dishes such as arsik (spiced carp), naniura (Batak "ceviche") and sambal andaliman.