Tips for canning crisp pickles at home include using freshly picked cucumbers, using non-waxed cucumbers, cutting off the blossom end, soaking cucumbers in ice water before pickling, and adding grape leaves to the pickles. Following the recipe precisely without altering the brine solution also helps the pickles stay crisp.
The natural pectin in cucumbers changes the longer they are off the vine, which causes them to become soft. Cucumbers from the store that have a wax coating don't soak up the brine solution well. Fresh cucumbers without wax help retain crispness.
The blossom end of the cucumber produces enzymes that soften the pickles, so cutting off that end prevents the enzyme production. Grape leaves inhibit the enzyme production if the blossom end remains on the cucumbers.