We have never experienced tough bok choy leaves and we’ve been buying and eating all varieties of bok choy for a long time. Both our local Asian market, WF, and a local market chain sell really fresh bok choy. We have steamed it, stir-fried it, and tossed it into hot pot. It seems to me that we have even cooked stir-fries with Chinkiang vinegar without the effect mentioned.
