Maybe it depends on where you live, but I know that lots of the pinto beans we buy around here are not processed with soy. There are farms in Colorado which grow pintos and not soy, and also in Farmington, New Mexico the Navajo tribe grows pinto beans - I don't think they grow soy there....
If I were you, I'd ask at the bulk department of a natural foods store about the sources for various kinds of beans. If that doesn't pan out, look into buying Southwestern beans. We're definitely not soybean country around here, and I know lots of New Mexican farms that grow pintos anyway, if not other types of beans too. It works well for us to buy 50-100 pounds of beans at once, and store them in airtight tubs. That way, we have all the beans we need for about a year or so.
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