The dry pack canneries associated with the Church of Jesus Christ of Latter-Day-Saints suggest that they are good for thirty years, I believe. That is 29 years longer that I would like to use them.
My aunt who lives in South Western Colorado on the plateau near the border of Colorado and Utah where pinto beans are dry farmed (whew) says that you should keep beans one year from harvest then throw them out and get new ones.
The grocery store beans may be over a year old when you purchase them, It would be really difficult to know unless you understand the packing codes. What does the 'use by date' tell you about when they were packed?
May I refer you to a little bean bible that I got somewhere, most likely stole it from my mother's cookbooks. It is called "The El Paso Chili Company. Beans." It is hard to tell what the title is because one is written over the other on the book jacket and simply "Beans" on the Title Page. Author is W. Park Kerr, a co-owner of the El Paso Chili Company at the time it was published in 1996.
I do enjoy this little book. It gives lots of information on beans and bean cookery. Kerr states: "Dried Beans are virtually immortal, having remained edible (that is cookable and even growable) for hundreds of years." He does qualify that statement with "they will just take a little longer to cook."
That is an understatement. In my experience beans that have been in storage a while (two or more years) do take longer to soak and cook. A lot longer. I soak my older beans for at least thirty-six hours and cook for all day or more in the crock pot.
Here is a tip from one of my daughters who researches these things. Put a tablespoon or so of whey in the soaking water. It does something to the beans to make them more digestible. I use whatever whey I happen to have on my cottage cheese, yogurt or Kefir. It is the watery part that you probably throw out. It is great for soaking beans and grains.
Some beans rehydrate faster than others, but they are not done until they are al dente and that does not mean slightly undercooked. It means simply to the tooth [you bite them in half and feel how they chew.], and pasta may continue cooking after drained, but beans don't. Undercooked beans are the major cause of gas. In my experience the softer they are the less likely they cause gas or constipation. They just have to be done or they don't digest properly.
A little antecdote my uncle used to tell. He said my aunt always cooked a potato in the beans to soak up the gas. Then she would eat the potato.
I plan to feature bean recipes for a while on Monday Soup Day. When my family was young I always made soup or stew and hot homemade bread on Mondays. I still make the soup, but not the bread. I will heat up Costco's pitas slathered with butter or bakery French bread toasted with butter and sometimes garlic bread seasoning, make scones or biscuits. It depends on the soup and what compliments it.
Enjoy your beans. Learn to cook them and eat them. They are good for you (says your mother).
HAPPY BEAN COOKERY