I grow bush and pole bean of various varieties, mostly to make pickled green beans. I want to find a variety to grow that is string - free, long and straight, bright green, with good flavor. I like my pickled beans to be crispy.
The tradition has been to use the Blue Lake variety for canning and pickling, even though Kentucky Wonder is judged as having a fuller flavor. One has to be careful with Blue Lake, as it is being bread for easy mechanical harvesting, with less attention being paid to flavor, according to the UCSC Agrecology Center.
When I grow stuff, I buy my seeds from Burpee. The customer favorites list for snap peas (what they are now calling string beans, as the string is gone in many varieties) lists a stringless cross between Blue Lake and Kentucky. That would be my choice for a pickle. I would try to grow them slowly by not overwatering, as that increases the calcium content of the plant and how well the beans keep their texture submerged in a jar.