success! finally, after years of trying, I got beans to come out tender with only a few minutes of applied heat, hayboxing until done. it took 3 times on the stove, and over a kilo of beef bones added for thermal ballast, hayboxing for several hours each time and adding water after each, until I opened it up tonight and knew from the first look I had a winner.
the beef bones, or maybe it was the bicarb, gave the whole thing a hint of a soapy smell and taste, but salt and pepper masked it well enough. I'm not even sure the bicarb was necessary, but I saw in a forum that it was recommended to break down the outside of the bean.
and it may have just been that 3rd time that was the charm. but I'm pretty certain that the bones holding the heat would have helped the passive cooking. maybe stones would do just as well.
last updated 2015-12-30 01:28:52. served from tektonic.jcomeau.com