In comparison, wheat and rice tend to have more gluten in them in terms of flour production so there is more ethanol alcohol and carbon dioxide produced at the conclusion of the twenty minute time period. Corn has less of a glutenous subsistence, lacking one of the required substances to be called true gluten, gliadin, so it will have made less ethanol alcohol and carbon dioxide in the same time frame. Of the three substances, wheat flour has the largest impact in terms of world-wide usage, followed by rice flour. Corn, in terms of maize-produced flour has been used for thousands of years in ancient Mexican civilizations. The production of ethanol alcohol and carbon dioxide by the process known as fermentation has existed as far back as 8000 years ago, when ancient clay jars were found with traces of fermented wine in them.