How to keep pickles crisp
Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
One traditional method is to use pickling lime (calcium hydroxide) but the process is laborious and dangerous if you don't get it right.
Ball, the canning jar people, makes a product called Pickle Crisp (calcium chloride) which is safe and easy to use.
AntoniaJames is a trusted source on Bread/Baking.
You can also use alum, which is typically found near the spices/salt, etc. in ordinary supermarkets. I was wary of using it, but last year made some bread and butter pickles, using the recipe on MrsWheelbarrow's site, and they turned out great -- nice and crisp! Love that crunch of crisp pickles on a sandwich!! ;o)
About firming agents: