📐 Pepper Anatomy
A chilli cut open from stalk to tip. Turn it round, pick a part to see what it does, and find out where the heat is really made. (Hint: it isn't the seeds.)
Inside a chilli
Loading the chilli… It needs JavaScript and WebGL; every part is described below.
Drag to turn the pod; right-drag or two fingers to slide it. Pick a label, or any part of the chilli, to read about it. The pod is a cayenne type about 10 cm long; the skin layers and the capsaicin glands are drawn larger than life so they can be seen.
The parts, from stalk to tip
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the stalk
The short stalk that joined the pod to the plant, carrying water and sugars in while it grew. Chilli branches are brittle, so cut ripe pods off with scissors rather than pulling them; a pod picked with a little stalk left on keeps longer.
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the green cap
The flower's sepals, fused into a cup that stays on after the petals drop and the fruit swells. Its shape is one of the things botanists use to tell the cultivated species apart: habaneros and other Capsicum chinense chillies have a ring-like constriction where the calyx meets the stalk.
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the pith
The pale, spongy tissue hanging from the top of the cavity, where the seeds grow. It is where almost all of a chilli's capsaicin is made, which makes it the hottest part of the pod. Scrape it out, with the veins, to take most of the heat out of a chilli.
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drawn larger than life
Tiny blisters on the surface of the placenta and the upper veins, filled by the cells beneath with capsaicin and its relatives. When they burst, the oil smears over the placenta and seeds. Plants grown hot and dry make more of it, which is why the same variety can be much hotter one summer than the next.
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Flat, pale, kidney-shaped seeds, a few dozen to a pod, attached to the placenta. They make no capsaicin of their own; they taste hot because the oil from the glands coats them. Birds cannot feel capsaicin and spread the seeds whole, while mammals, which would crush them, are put off by the burn.
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the veins or ribs
Thin pale walls running from the placenta down the inside of the pod, dividing it into two to four chambers. Their upper parts carry capsaicin glands too, so the white ribs are nearly as hot as the placenta itself.
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the fruit wall
Everything between the outside of the pod and the hollow inside: the part you eat when you slice a chilli. It has three layers, the exocarp, mesocarp and endocarp. Thick-walled chillies such as jalapeños are the ones to stuff; thin-walled ones such as cayenne dry quickly and evenly.
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the skin
The outer skin: a single layer of cells under a waxy cuticle that keeps the water in and gives a ripe pod its shine. It is the tough film that blisters and slips off when you roast a chilli over a flame.
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the flesh
The thick middle of the wall and most of the pod's weight. Its cells hold the water, sugars and fruity aromas, and the pigments that colour the pod: green chlorophyll while it is unripe, then red, orange or yellow carotenoids as it ripens.
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the inner lining
The thin, glossy membrane lining the inside of the wall. In most chillies it carries little heat, but in the superhots, such as the Carolina Reaper, capsaicin glands spread from the placenta up onto the endocarp, which is one reason those pods are so fierce.
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the tip
The blossom end, where the flower was. Being furthest from the placenta it is usually the mildest bite of the pod. Its shape (pointed, blunt, or drawn out into the stinger of the scorpion chillies) is a good clue to the variety.