if a little it of ALUM helps firm them up alot add it to the salt mixture at a value of 1 part Alum to 10 parts salt... you could also use cinnamon, mustard seed, bay leaves, allspice, dill seed, cloves, ginger, peppercorns, coriander, juniper berries, mace, and cardamom for other flavors. For a hotter mix, add some crushed hot peppers.