This is the most common issue that readers have had and it is all to do with the beans. I've had some be almost mushy in 30 minutes and some take almost 2 hours. You just have to keep testing them as they boil. There are no hard-and- fast rules as to why dried beans take longer to cook because it seems every batch of beans are different (see below at my test results on this). A few reasons could be, they are old beans. You can't be sure how old they are, even if they are within their expiration date. You have hard water. Hard water can toughen the skins. You didn't soak long enough. 8-12 hours is optimal but no more than 24.