I have found a way to locate pebbles in beans that finds even the well camouflaged ones. Most recipe books have you search for the rocks prior to soaking them.
I measure out and soak my legumes first. Then I thinly spread a layer of them on a metal tray or cookie sheet, metal is important. I then spank the back of the sheet with a wooden spatula. If there is any rock in the tray, it will have a distinctive ping. The soaked beans will have a dull sound.
Photo of my favorite "Bean testing Tray". The handles on both sides accentuates the rock ping. Though a rock still sounds different than the beans if your holding on to the tray with your hand, not touching the tray with your hand makes it even more distinctive.
I test a handful of soaked beans at a time.
Simple ways Simply work
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