Steve Brush at UC Davis did work in the Peruvian mountains. Wendell Berry mentions him in whichever book that was. Steve can be reached at sbbrush@ucdavis.edu, or Dept of Human and Community Dev't, Univ of CA, Davis, CA 95616 (I don't have the 'phone). He said he remembers the preparation of chuno, and would be glad to talk to folks about it. Bill Blake