Okey-dokey. Quite a few questions here:

1. Pickling Spice is a blend of whole spices. Generally the most prevalent spice is mustard seed with varying amounts of other whole spices like cloves, cinnamon, coriander, dried red peppers, etc.

You can buy Pickling Spice bottled (expensive) in the spice section of any grocery store. Some stores also carry it in bulk. Bulk, even paying online for shipping, is much cheaper. I buy in bulk and keep the excess in the freezer, but vacuum-sealing would also work.

Each company offers its own proprietary blend, so sometimes you'll find one blend you like better than another. For example, Penzeys uses lots of anise, which is a bit much for my taste. But I blend that with American Spice's pickling blend and am very happy with the results.

You can also blend your own pickling spice from whole spices you may already have on the shelf. I think some old threads offer some posted recipes, but if not I could provide a typical one.

2. Any pepper of any color can be safely switched for another as long as the total volume or weight remains the same. Dried peppers can always be added to that for additional color and heat. One or two can really add perk up the appearance of a jar of pickles.

3. You can always safely reduce jar size (keeping the same processing time) but you can't size up unless the recipe says you can. Sometimes a pickle will specify pints or quarts with the same processing time. Sometimes a pickle will specify increased processing time for quarts. Just follow the instructions.

It would be very unusual (I can't think of any off-hand.) for a recipe to specify quarts for a relish as the mixture would be quite dense with that volume. Canning in quarts would be a mistake, but if the relish was quite liquid and used, say, 100% vinegar, I probably wouldn't worry about it. I'd just use those jars first. But if it's quite a dry mixture (something to be avoided generally) I might just toss it, especially as we're in a new season.

I think that covers everything.

Carol

Here is a link that might be useful: Spice House Pickling Spice

That was probably a mistake?

Agree with Carol. That would be a mistake. Those jars are under-processed and not safe for shelf storage and it is too late to reprocess them now.

should I assume that is not safe to change jar size?

Yes you should and that applies to all canning recipes.

You can always reduce jar size (but process for the size jar in the recipe instructions) but you can never increase jar size over what is called for in the recipe instructions.

All the major spice brand manufacturers make Pickling Spice. If not in the Spices section of the store it will be with the canning supplies.

Example: McCormick Pickling Spice

Dave

Thank you for your comments. You both have been a big help!