Chicha from the great beyond

The basic recipe for beer goes something like this.You take starch from a cereal grain (the fruit of a domesticated species of Poaceae, or Grass family), use enzymes to convert that starch into sugar, feed the sugar to a microbe capable of fermentation (such as a yeast or bacteria), which then poops out alcohol and carbon dioxide. It’s a beautiful process. You see the barley – brewer’s yeast – hops combo all the time. But why be so predictable?

Instead of barley, how about something more Western Hemisphere, how about maize (Zea mays, aka corn)? And instead of enzymes which naturally occur within the germinated grain, how about something more… personal? And instead of good old brewer’s yeast, how about something from beyond the grave, specifically a 1300 year old Quitus tomb in Ecuador?

Chicha is an alcoholic beverage which originated in Central and South America. It uses ground maize as its base, which was domesticated around 9200 years ago in south-central Mexico.  To begin the process, ground maize is added to water. But un-germinated  maize lacks the enzymes found in germinated (malted) barley, so the peoples of Central and South Amercia came up with a clever alternative. Amylases, which convert starch into sugar, can be found naturally in several places, including human salivary glands. Traditional chicha makers would chew kernels of maize to get the salivary glands pumping, and then spit the juicy mass into the container of ground maize and water. There the salivary amylase would get to work, breaking the starch down into the sugars maltose and dextrin. But that’s only half the process.

To produce alcohol, you need a microbe capable of fermentation. Wild yeasts and bacteria with this ability are abundant in the environment, and so you could just wait, and let whatever comes along populate your sugary liquid. But the results would be… unpredictable. Luckily, the chicha maker’s spit-take has a one-two punch: along with the required amylase, it also carries human-commensal  yeasts which live in the mouth, such as members of the Candida genus. They do the trick nicely. You may remember Candida  from such wonderful diseases as thrush and yeast infections?

Modern commercial chicha is made from germinated corn, which produces its own amylases, and typical brewer’s yeast. But some people have to be as authentic as possible. Recently, several species of Candida, including a new species, Candida theae, were identified and resurrected from scrapings of chicha vessels found in a Quintus tomb in Ecuador, dating back to 680 AD. Of course the yeast biologist involved, Javier Carvajal Barriga, had to try them in his own chicha; apparently delicious, expect for the wicked hangover.

Scrapings from chicha fermentation vessel. From Scientific American.

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