Pan-Thai — chilli cultivation arrived with Portuguese traders in the 16th century and was fully integrated within 100 years
Thai cuisine uses at least five distinct chilli types in regular cooking, each with different heat profiles, flavour compounds, and applications. Prik kee noo (bird's eye chilli, Capsicum frutescens) is the hottest, used fresh in dressings, stir-fries, and as a table condiment — its thin walls mean heat hits immediately. Prik chee fah (spur chilli, Capsicum annuum) is long, mild, and flavour-forward with low heat, used in curry pastes, stir-fries, and garnishes. Prik haeng (dried spur chilli) brings a deep red colour and roasted depth to pastes. Prik yuak (banana chilli) is large, mild, and used stuffed or in gaeng pa. Understanding which chilli does which job is fundamental — substituting bird's eye for spur chilli produces a curry paste that is incendiarily hot with little flavour.
Chilli in Thai cooking is not solely about heat — it is a flavour ingredient. Bird's eye chillies add sharpness and citrus-adjacent brightness; dried red chillies add depth and colour; fresh long green chillies add vegetal sweetness.
{"Prik kee noo: maximum heat, minimum flavour — use for sharpness and fire, not colour","Prik chee fah: mild heat, maximum colour and sweetness — the backbone of red curry pastes","Prik haeng (dried): roasted, smoky depth — always rehydrate before pounding or dry-toast for curry pastes","Seed removal reduces heat by approximately 40–60% — the capsaicin is concentrated in the pith, not the seeds","Heat in fresh Thai chillies is volatile — dishes cool rapidly and the burn fades; dried chilli heat lingers"}
For paste work, the ratio of prik chee fah to prik kee noo determines both colour and heat — most commercial pastes use 8:1 or more in favour of the mild chilli. If your green curry paste comes out pale and insipid, you've used too few long green chillies; if it comes out fire-engine hot, too many bird's eye.
{"Using only bird's eye chillies in curry pastes — produces flat, hot, uncoloured paste","Not rehydrating dried chillies before pounding — they don't break down and leave fibrous chunks","Substituting jalapeños or serranos — wrong capsaicin compounds and completely different flavour profiles","Treating chilli heat as binary (hot/not hot) rather than understanding the flavour dimension of each type"}