Originally Posted by mcnerd
Hmmm, my authority at Dummies.com
says "Never add salt to the soaking or cooking water when initially preparing beans. Salt prevents the skin from softening, making for a tough, not-too-tender bean. Always season the beans after they're done cooking. Like little sponges, they'll absorb the salt quite quickly and be flavorful."
I always add acid in the form of vinegar to inhibit the creation of the gaseous side effect.
Your information from "dummies" has been contradicted by reputable food scientists like Shirley Corriher, Alton Brown, Harold McGee and the likes of the folks at Cooks Illustrated. Also by my own personal experience over many more years that I'd like to admit.
Salt doesn't inhibit softening. Acids, sugar and calcium do. Also old beans may refuse to soften no matter what.
Salting cooked beans doesn't help them much. Like Alton Brown said "if you wait until (the beans are) finished to add the salt they're going to taste like papier-mâché."
Oligosaccharides, the sugar that causes gas, are water soluable and not counteracted by acids. They have been thought to be counteracted by mold, so maybe there's some marginal effect from a fermented product like vinegar, but you're probably offsetting some small improvement in flatulence by risking a crunchy end product.
For what America's top food scientist has to say, here's the actual text of "On Food and Cooking"where McGee explains cooking beans.
Alton on beans
Discussion about cooking beans here