I cooked pinto beans in an electric pressure cooker and ended up with a few overcooked mushy beans, few cooked ones, if slightly al dente, and the majority of beans so severely undercooked that they seemed to be hardly cooked at all. Over- or undercooked beans wouldn't have surprised me, but both at the same time? What happened?
I used my newish electric pressure cooker to cook dried, not soaked, pinto beans. I cooked 250 g (9 oz) in 1 litre (4 cups) of water on high pressure for 22 min (the accompanying booklet recommended 22-25 min) and did a quick release (I did 24 min and natural release before; this resulted in beans so mushy you cannot eat them as anything else other than puree; internet research pointed towards 22 min and quick release). Where was my mistake?