Castanha de caju

Ingredients

Nuts

• 1.5 kgraw cashew nuts in the shell, sun-dried for 2–3 days after harvest
• A perforated steel drum, an old wok or a heavy iron pan, used outdoors over a wood fire
• Dry sand, about 1 kg, if roasting in a pan

Protection

• Thick leather or rubber gloves
• Long-handled tongs and a stirring paddle
• Ash or wood ash, for rubbing the hands and the nuts

To finish

• 1 tspfine salt
• A little groundnut oil, optional, for re-roasting

Directions

1. Twist the nuts off the cashew apples at harvest and dry them in the sun on mats for 2–3 days, until the shells rattle and are hard.
2. Build a wood fire outdoors, upwind, and set the drum or pan over it. This is never done indoors, for reasons that become clear in the next step.
3. Tip the nuts in and roast, stirring with a long paddle. Within a few minutes the shells begin to ooze and then flare, because the shell is full of caustic cashew nut shell liquid, which catches fire and burns off with thick black smoke.
4. Let the shells burn and blacken for 3–5 minutes, keeping the nuts moving so they do not scorch through, then smother the flames with a lid or by tipping the nuts into sand or ash.
5. Rake the hot nuts out onto the ground and rub them through wood ash or dry sand while still warm. The ash absorbs the remaining caustic oil and stops it burning your hands.
6. Leave them to cool completely, at least 30 minutes; hot shells are far harder to crack cleanly and still carry active oil.
7. Crack each nut by laying it on a flat stone and giving it one sharp, controlled tap with a wooden mallet or a smaller stone, splitting the shell along its curve without crushing the kernel inside.
8. Prise the kernel out and peel off the thin brown testa with a fingernail; if it will not come away, dry the kernels in the sun for another hour.
9. Toast the shelled kernels in a clean dry pan over low heat for 8–10 minutes, shaking constantly, until pale gold and fragrant, then toss with salt while hot.
10. Cool completely before storing in an airtight tin. Warm nuts sweat in the jar and turn soft and rancid within days.

Technique

• The cashew shell contains anacardic acid and cardol, chemically related to poison ivy. The liquid raises blistering burns and the smoke from roasting is a serious respiratory irritant. Roast outdoors, upwind, with gloves, and never over a kitchen stove.
• There is no such thing as a genuinely raw commercial cashew. Every cashew sold to eat has been heat-treated to destroy that shell oil; the pale nuts labelled raw have been steamed rather than roasted.
• Guinea-Bissau lives on this crop. Cashew is around 90 per cent of its export earnings, and almost all of it leaves the country in the shell to be processed elsewhere, which is why hand-cracked local nuts are so prized.
• The cashew apple is not waste. It is juiced, drunk fresh, or fermented and distilled into the local cana de caju spirit.

Substitutions

• Do not attempt shell roasting at home if you cannot work outdoors with proper gloves. Buy shelled raw kernels and start at the pan-toasting step instead.
• No wood ash: dry sand works for rubbing the roasted shells, and is what many small producers use.

Variations

• Plain salted castanha, sold in twists of paper at every roadside in Bissau.
• Castanha roasted with chilli and salt.
• Cashew apple juice and the distilled cana de caju, made from the fruit the nuts hang from.

History

Cashews were brought from Brazil by the Portuguese and now dominate Guinea-Bissau’s exports and farmland, making the country a leading producer.

Frequently asked questions

What is Castanha de caju?

Castanha de caju is a snack from Guinea-Bissau: cashews roasted over fire and cracked from their shells by hand. Cashews were brought from Brazil by the Portuguese and now dominate Guinea-Bissau’s exports and farmland, making the country a leading producer.

How long does Castanha de caju take to make?

Castanha de caju takes 30 min of preparation and 45 min of cooking. The recipe makes about 400 g shelled nuts. It is rated medium to make.

What can I substitute in Castanha de caju?

Yes, within limits. Do not attempt shell roasting at home if you cannot work outdoors with proper gloves. Buy shelled raw kernels and start at the pan-toasting step instead. No wood ash: dry sand works for rubbing the roasted shells, and is what many small producers use.

What is the most important thing to get right in Castanha de caju?

Build a wood fire outdoors, upwind, and set the drum or pan over it. This is never done indoors, for reasons that become clear in the next step.