1. Wash beans and drain. Trim ends and cut into 2" pieces, or leave whole (if packing vertically).
2. Tightly pack raw beans into washed, hot jars, add 1/2tsp salt and top with boiling water, leaving 1" headspace.
3. Wipe rim, center lid on jar, screw band down.
4. Place jars in pressure canner. Adjust water level, lock lid and bring to a boil over medium-high heat. Vent steam for 10 minutes, then close vent. Continue heating to achieve 15lbs of pressure and maintain pressure for 20 minutes for pint jars and 325 minutes for quart jars.
5. Turn off heat. Let pressure return to zero naturally. Wait 2 minutes longer, then open vent. Remove canner lid. Wait 10 minutes, then remove jars, cool and store.
Recipe from Ball Complete Book of Home Preserving, pages 385 and 386.