When I tried to keep some unblanched runners for Christmas, they tasted horrible.Since then I have always blanched them for two minutes and they last really well
Blanch for 2 mins in water or steam and then plunge into ice cold water STRAIGHT AWAY to stop the cooking.
Oh blast!Last year I blanched my beans and they were all pappy when we had them, so this year I haven't bothered blanching. Please don't tell me they will be horrible unblanched.....otherwise I'll give up growing them.