Pato no Tucupi (Duck in Tucupi with Jambu)

Variations

• With boiled duck: many households boil the duck first instead of roasting it, then add it to the tucupi. The broth is cleaner and lighter, and there is no roasted skin. The photograph shows the roasted version.
• Tucupi in other dishes: in Belém the same broth goes into tacacá, a street food served in a gourd bowl with prawns, jambu and tapioca starch. Tucupi is less an ingredient of one dish than the region's broth.
• Without jambu: better to serve it without than to fake it — there is nothing that stands in well. See the romazava note in the Tips.
• With chicken: chicken in place of duck needs 40 minutes in the oven and 20 in the broth. But in Belém this broth's partner is duck.

Tips

• The broth here is the water everyone else throws away. Tucupi is the juice wrung out of grated cassava when cassava flour is made. Attiéké, which works the same root, presses its fermented mash and says "That liquid is discarded". Cepelinai catches the water squeezed from its potatoes, lets the starch settle and then says "Pour off the clear water carefully" so that only the white sediment is kept. Tucupi is the yellow liquid above that sediment. The settled starch becomes tapioca, and the wrung-out pulp is dried into the cassava flour served beside the plate. Of the three things one root gives, two are on this plate.
• The poison is in the liquid, and a pot takes it out. Cassava is cyanogenic. Rawon sets itself beside fufu, which peels the root thickly and throws that part away: "Rawon spends weeks changing the part that was the poison and then eats it. Same problem, opposite solution." Tucupi does not sit on either side of that. The poison is in the juice, and hydrogen cyanide is volatile — boiling drives it off in the steam — so fermented juice boiled long enough is made safe. Not weeks of burial in a solid, but a pot on the boil.
• That boiling was finished outside your kitchen. Tucupi as sold has already been through it, and attiéké says as much of the root itself: "Bitter varieties are not a home project." The 20 minutes in this recipe are for flavour, not to make raw juice safe. Buy from a reliable source only, and throw away anything that looks or smells wrong.
• Tucupi is sour. It is a fermented juice, so it is sour and savoury at once, which is why a fatty bird is its partner. Pouring off the fat in the oven and skimming it in the pot keeps the broth from turning heavy.
• Jambu is not heat but tingle. Jambu is the same plant as the mafana in romazava — paracress — and that page has already explained it: spilanthol. "It tingles, numbs a little, and makes the mouth water." Romazava cooks the leaves in the soup for two minutes; here they are blanched separately in salted water and go in at the end. If the tip of your tongue buzzes after the first spoonful, it is in there properly.
• Do not thicken the broth. Tucupi's starch was settled out and removed before it was sold. The broth is meant to be thin; the cassava flour is scattered over on the plate a little at a time to soak it up.