Pickling spice is a mixture of various spices to be added to the vinegar when making pickles and chutneys. Black peppercorns, red chillies, allspice, cloves, ginger, mustard seed, fennel seed, cardamom may be included. Here's a mix for pickling spice that can be varied according to your taste:
1 level tbsp mustard seed
1 level tbsp whole cloves
1 cinnamon stick, broken in 2 pieces
4 cardamom pods
6 black peppercorns
1 bay leaf, crumbled
Mix all the ingredients together and store in an airtight jar in a cool dark place (not the fridge). Will keep for up to one month. Weigh out the required amount for your recipe and tie in a muslin bag to use.