Analysis of information sources in references of the Wikipedia article "Argile" in French language version.
« The Pomo Indians in California and natives of Sardinia used similar methods to make acorn bread (2, 2 1). The Pomo mixed clay with the ground meal of bitter acorns (principally Quercus lobata) in a ratio of 1 : 10-1 :20 by volume. Water was added to make a dough, and small loaves were baked gently in an earth oven for 12 h. Breads were made without clay from nonbitter acorns or from meal from which tannic acid was removed through a leaching process. (…) Recipes used by the Pomo called for clay: acorn ratios of 1: 10-1:20 by volume (“- 1 :5- 1:10 by weight). (…) Cooking acorns with clay reduces the toxicity of acorns caused by protein precipitation by as much as 77% . »
« The Pomo Indians in California and natives of Sardinia used similar methods to make acorn bread (2, 2 1). The Pomo mixed clay with the ground meal of bitter acorns (principally Quercus lobata) in a ratio of 1 : 10-1 :20 by volume. Water was added to make a dough, and small loaves were baked gently in an earth oven for 12 h. Breads were made without clay from nonbitter acorns or from meal from which tannic acid was removed through a leaching process. (…) Recipes used by the Pomo called for clay: acorn ratios of 1: 10-1:20 by volume (“- 1 :5- 1:10 by weight). (…) Cooking acorns with clay reduces the toxicity of acorns caused by protein precipitation by as much as 77% . »