Thai green curry gets its colour from the fresh green chillies, kaffir lime leaves, and coriander blended into the paste. That’s really all there is to it. Whether you follow a vegan Thai green curry recipe or the traditional version, the green colour comes from exactly the same source.
How Thai green curry gets its colour
Thai green curry, or “Gaeng Keow Wan” as it’s known in Thai, balances coconut milk, green chillies, and a mix of fresh herbs and spices. The colour is not incidental: it comes directly from the raw green ingredients pounded into the paste, with no dyes or additives involved.
The green stands out clearly on the plate before you even taste it. It reflects the lush Thai landscapes where basil, kaffir lime leaves, and green chillies grow in abundance.
Why is green curry green: the green chillies in the paste
The primary source of green curry’s colour is Thai green chilli peppers, often called “Phrik Khi Nu.” Green bird’s eye chillies are noticeably hotter than the dried red chillies used in red curry paste, which is why green curry usually outburns red despite what the colours might suggest. For a full breakdown of where these chillies land on the heat scale, see my guide to Thai chilli vs habanero heat.
The bird’s eye chillies
The specific variety of green chilli used in green curry is the bird’s eye chilli. These chillies are known for their intense spiciness and their bright green colour. The hue comes from a combination of ripeness, pigment concentration, and the natural variation in chilli peppers.
The role of ripeness
The stage of ripeness at which the bird’s eye chillies are harvested affects the depth of green in the curry. Young, unripe chillies tend to have a more vivid green colour because of the higher concentration of chlorophyll, the green pigment responsible for photosynthesis in plants.
Understanding chlorophyll
Chlorophyll is what drives the green colouration of plant tissues, including green chilli peppers. As the chillies mature and ripen, chlorophyll levels decrease, giving rise to other pigments such as red and yellow carotenoids. That is why red and yellow chillies also appear in Thai cuisine, though they are quite different from the unripe bird’s eye chillies used here.
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How the paste is made
In the traditional preparation of green curry, the green chillies are pounded into a paste together with lemongrass, galangal, garlic, shallots, and other spices. Pounding releases the colour from the chillies and distributes it through the paste. I show you exactly how this is done in my guide to how to make Thai green curry paste the Thai way.
No artificial colours or additives
There are no artificial colourings or additives in a proper green curry. The colour comes entirely from fresh green chillies and herbs pounded into the paste. If you’re wondering whether red or green Thai curry is hotter, the answer may surprise you.
The short answer
Green curry is green because of the fresh green chillies in the paste. That is the whole explanation.
