Care For A Glass Of Chicha?

by Elio

Fig­ure 1. Glass of chicha. Source

Al­co­holic bev­er­ages typ­ify hu­man so­ci­eties. Think of cham­pagne and the French, scotch and the Scot, and so on. In the West­ern re­gions of South Amer­ica, mainly Peru, Ecuador, and Colom­bia, the main ar­ti­sanal al­co­holic drink made by the na­tive peo­ple is called chicha. It is the prod­uct of fer­men­ta­tion of one of var­i­ous grains, the main one be­ing maize. Cas­sava (man­ioc), quinoa, the fruit of the chonta palm, and oth­ers are also used. What typ­i­fies some chicha from Ama­zo­nia is that the ma­te­r­ial to be fer­mented (cas­sava) is first cooked (boiled) and then chewed into a pulp by will­ing par­tic­i­pants, tra­di­tion­ally women. The "chewate" is then placed in vats where fer­men­ta­tion takes place. It is ready for con­sump­tion as quickly as 2–3 days af­ter prepa­ra­tion. Chicha has a no­table his­tory. It was used for rit­ual pur­poses by the In­cas, tra­di­tion­ally pre­pared by the "vir­gins of the sun."

I spent my teen years in Ecuador, but be­ing young and rea­son­ably ab­stemious, did not par­take of chicha un­til I re­turned for a visit. En­ter­ing a "chichería," a place where the stuff is both brewed and con­sumed, I over­came my qualms in the spirit of mi­cro­bi­ol­ogy. I was aware that that the point of the chew­ing is to ex­pose the sam­ple to sali­vary amy­lase, which con­verts starch into fer­mentable sug­ars. The taste was ac­cept­able, al­though not likely to turn me into an avid "chichero."

The mi­cro­bi­ol­ogy of chicha has been stud­ied in some de­tail (see, for ex­am­ple, here, and here). It has re­cently been com­ple­mented by an el­e­gant and thor­ough re­port from the lab­o­ra­tory of Prof. Gabriel Trueba, of the Uni­ver­si­dad de San Fran­cisco in Quito, Ecuador. These work­ers iden­ti­fied the bac­te­r­ial strains present us­ing cul­tures and by 16S rRNA gene-based tag-en­coded FLX am­pli­con py­rose­quenc­ing (bTE­FAP). The most com­mon species en­coun­tered in the four sam­ples of chicha stud­ied var­ied in num­ber from 21 to 31. They also found in abun­dance the po­ten­tial pathogens, Strep­to­coc­cus sali­var­ius and S. mu­tans. Fungi were also present, the most pre­dom­i­nant be­ing Sac­cha­romyces cere­visiae.

Fig­ure 2. Chicha in the mak­ing. Source

Their main con­clu­sions were that hu­man saliva speeds the fer­men­ta­tion not only by pro­vid­ing the amy­lase that breaks the starch down to fer­mentable sug­ars, but also by de­liv­er­ing a suit­able bac­te­r­ial in­ocu­lum. More­over, the au­thors spec­u­late that chewed chicha could trans­mit po­ten­tial hu­man pathogens such as S. mu­tans, an im­por­tant agent of den­tal caries. So, drink­ing chicha may not just be fun.

 

Hear more about chicha in this episode of This Week in Mi­cro­bi­ol­ogy.