Papa and chuño — the Andean tuber and its freeze-dried form in the Spanish record
Three printings read here — Seville 1553, Seville 1590 and the Madrid reissue of Garcilaso — describe the papa, the frost-and-tread process that turns it into chuño, and the trade in that chuño which supplied the mines of Potosí. The technology recorded is Andean, not Spanish; what is Spanish is that it was set in type in Europe within twenty years of the conquest of Peru. Modern literature supplies the route out of the Andes and the famine at the far end of it.
Why this wins its question: The potato's exit from the Andes is normally told with a date, a port and a conquistador, none of which is documented, and the Andean side of it is reduced to "the Incas grew potatoes". This object quotes three printings from the page instead: the 1553 Seville description of a tuber that cooks as tender as a boiled chestnut, Acosta's 1590 explanation of why wheat and maize fail above the Collao and his sentence that the chuño trade supplied the mines of Potosí, and Garcilaso's step-by-step account of frost, straw, treading and sun, ending in the Inca pósitos. Then it puts the modern literature beside them and keeps its hedges — the Canary Islands route stated as a likelihood rather than a fact, and the Irish famine's near-million dead named as the cost of the dependence that followed. The dependency, the technology and the famine are in one place, each bound to what actually states it.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Cieza de León's Crónica del Perú, printed at Seville in 1553, describes the tuber on the leaf numbered xlix. Besides maize, he writes, there are two other staples "que se tienen por principal bastiméto entre los Indios"; the first is called "Papas, que es a manera de turmas de tierra", which after cooking is "tan tierno por de dentro como castaña cozida", has neither rind nor stone, and grows underground as the truffle does, the plant above it being "ni mas ni menos que la hamapola". The passage is a plain botanical description, written by a man who had walked the country, and it is in a book that went through the Seville press seventeen years after the fall of the Inca state.
Acosta's Historia natural y moral, Seville 1590, states the agronomic reason the tuber mattered. On page 240 he writes that in the high sierra of Peru and the provinces of the Collao — "que es la mayor parte de aquel Reyno" — the weather is so cold and dry that neither wheat nor maize will grow, "en cuyo lugar vsan los Indios otro genero de rayzes que llaman Papas". These are gathered, left to dry well in the sun and broken up. On the same spread he records the opposite failure in the Caribbean islands, where wheat sprouts but ripens so unevenly it cannot be harvested and flour has to be shipped in from New Spain, Spain or the Canaries.
The product of that drying is named on the next page: "que llaman chuño, que se conserua assi muchos dias, y les sirue de pan". Acosta then adds the sentence that turns a food into an economy — "y es en aquel Reyno gran contratació la deste chuño para las minas de Potosí". The freeze- dried tuber is what provisioned the silver mountain, which is to say that the labour drafted to Potosí was fed on it; the same page records that papas were also eaten fresh, boiled or roasted, and made into the stew "que llaman Locro".
Acosta also records the fragility of the system he is praising. "En fin estas rayzes son todo el pan de aquella tierra, y quando el año es bueno destas, estan cótentos, porq̃ hartos años se les añublan y yelan en la misma tierra: tanto es el frio y destemple de aquella region." A staple that fails in the ground in many years is on the record from the source that calls it the bread of the country.
Garcilaso de la Vega, in the Comentarios reales read here in the Madrid 1829 reissue, gives the process step by step and places it inside Inca administration. In the province called Colla, more than a hundred and fifty leagues long, the land is too cold for maize; among the crops that fruit underground "hay una que llaman Papa; es redonda y muy humida, y por su mucha humidad dispuesta á corromperse presto". To preserve it they lay it on straw, leave it many nights to the frost that falls all year in that province, cover it with straw and tread it gently so it gives up its water, press it, sun it and keep it from the night damp until wholly dry: "Desta manera preparada se conserva la papa mucho tiempo, y trueca su nombre y se llama Chuñu". All of it grown on the lands of the sun and of the Inca was so treated and stored "en los pósitos con las demas legumbres y semillas". Confidence sits below the other primaries because the copy read is a reissue of 1829, not the Lisbon sheets of 1609.
None of the three printings read here says anything about carrying the plant to Europe; the route is a reconstruction of the modern literature, and that literature hedges it. A 2016 review in Theoretical and Applied Genetics states that after the Spanish conquest of the Inca state in 1532–1536 the first potatoes were introduced into Europe "most likely via the Canary Islands, where the ships anchored on their way from America to Europe", that cultivation then spread slowly across Europe over four centuries and thence to the rest of the world, and that the potato is now the world's third food crop after wheat and rice. The Canary Islands step is given as a likelihood, not a documented sailing, and is reported here as such.
The cost at the far end of the transfer. Phytophthora infestans, the oomycete that causes late blight, emerged in the mid-1840s and rapidly became pandemic; Miles Joseph Berkeley identified it as the cause in 1846. The resulting failure, in the words of a 2013 eLife review, "led to almost a million deaths in Ireland and the emigration of many more, plus considerable loss of life and extreme political upheaval throughout mainland Europe". Neither the sixteenth-century authors nor the crown they wrote for chose the narrow set of genotypes that crossed the Atlantic, and no source read here apportions responsibility for the famine; what is on the record is that the crop Europe came to depend on arrived from the Andes and that its dependence proved catastrophic.
What the record does and does not credit to Spain. The tuber, its cultivation, and the freeze-drying that made it storable are Andean, and all three printings say so plainly — Garcilaso attributes the whole process to the practice of the Colla and to the Inca storehouse system. The Spanish contribution documented on these pages is narrower and worth stating exactly: description, naming in a European language, printing, and — in Acosta's case — an explanation of why the crop existed at all that is agronomically correct. The mine trade he records is the same transfer seen from the other side, since the market for chuño at Potosí was created by a labour draft the corpus treats under the mita.