Cauim (also cauí, kaui) is a thick, sour fermented drink made by Indigenous peoples of Brazil from cooked cassava – and, depending on the community, rice, maize or peanuts. It belongs to the same family of South American starch drinks as Amazonian masato and Andean chicha. Sixteenth-century European accounts of the Brazilian coast describe Tupi-speaking peoples brewing it for communal gatherings, with women chewing part of the cooked cassava.
Why the Cassava Was Chewed
Yeasts can’t ferment starch, only sugars. Malting grain is one way to supply the enzymes that turn starch into sugar; chewing is another. Saliva contains the enzyme amylase, and chewed cassava returned to the pot is partly broken down into sugars that yeasts and bacteria can then use. (Populations with long histories of high-starch diets tend to carry more copies of the salivary amylase gene, AMY1 – Perry et al., 2007.)
What Ferments Cauim
The best microbiological study comes from the Tapirapé of Tapi’itãwa, among whom cauim is described as the main staple for children up to two years old and their parents (Almeida et al., 2007). Following a mainly cassava-based batch, the researchers found:
- a steady fall in pH from 5.5 to 3.4;
- lactic acid as the main product, with significant ethanol and acetic acid;
- lactic acid bacteria – above all Lactobacillus plantarum and L. pentosus – dominating throughout, alongside smaller numbers of yeasts;
- spore-forming bacteria including Bacillus cereus, a food-poisoning species, among the isolates.
Cassava Safety
Cassava roots contain cyanogenic compounds. Australia and New Zealand’s food standards body requires cassava to be labelled as needing to be peeled and fully cooked, notes that boiling, steaming, baking or frying remove between 10 and 75% of these compounds, and advises discarding the cooking water (FSANZ). Use sweet cassava, peel it completely, boil it in plenty of water and throw that water away. For more, see our guide to fermented cassava staples.
A Home Adaptation
Chewing isn’t practical or appropriate outside the communities that do it, so the recipe card below uses malted barley flour as the enzyme source – which makes the drink not gluten-free. The cooked, mashed cassava is held at about 60–65°C with the malt so its enzymes make sugar, then cooled and left to ferment spontaneously for two to three days. Expect a sour, slightly alcoholic drink; because Bacillus spores can survive cooking, keep the vessel clean, don’t let the mash sit lukewarm for long before fermenting, and refrigerate once it’s sour.