This water-bath canning recipe is adapted from the tested Ball canning recipe for Peach Rum Sauce with only safe variations, so you can can with confidence.
Bring a large pot of water to a boil, and blanch the peaches for 10-30 seconds.
Put the blanched peaches into a bowl of lemon water large enough to hold the peaches without overflowing (add several tablespoons of lemon juice or 2-3 teaspoons of citric acid). This will help keep the peaches from oxidizing and turning brown.
When they are cool enough to handle, peel the peaches. The skins should slip off easily. If they don't, you can return them to the boiling water pot or use a paring knife.
Cut the peaches in half, remove the pits, and cut into large diced pieces. Measure out 6 cups of peaches, and return them to the lemon water bath while you measure other ingredients. Save and dry the pits to make noyaux, if you like, and the skins for fruit vinegar (or compost or discard).
Make the Whiskey Peach Sauce
Into a large, heavy-bottomed jam or sauce pot, add the brown and granulated sugar, whiskey, salt, and coriander. Drain the 6 cups of diced peaches and add them to the pot.
Bring to a boil over high heat. Stir constantly until sugar has dissolved, then reduce heat and stir regularly.
Let the sauce simmer at least 20 minutes, or until thickened. While the sauce is simmering, proceed with step one of the canning instructions.
Water-Bath Canning Instructions
Fill your water bath canner with water to a height that will cover your jars by several inches with room to boil vigorously. Wash your half-pint or 4 oz jars and canning lids with hot soapy water, rinse, and place the jars (but not the lids) in the canner as you bring the water up to a simmer.
Protect your work surface- I like to use a baking sheet pan lined with an old kitchen towel. Remove your canning jars from the canner (carefully, with tongs or jar lifters, tilting them out of the hot water) just before filling and place them on the sheet pan or counter lined with a towel. This helps protect the jars from temperature shocks and also makes for easier clean-up!
Using a jar funnel if you have one, ladle the hot peach sauce into the hot jars. Leave between ¼-½" of headspace at the top of the jars (¼" unless you are using reusable-style lids with gaskets like Weck or Tattler).
Debubble the jars with a thin spatula, spoon, or debubbling tool, and wipe the tops of the jars with a clean paper towel or lint-free cloth that has been dipped in hot water or vinegar.
Place the canning lids on the clean jar tops and screw down the rings- don't overtighten, just snug. Using your jar lifter, tongs, or the canning jar rack, carefully place the hot filled jars in the hot canner.
Make sure you have adequate water covering the jars (at least 2" over the tops of the jars). Top up with water from a hot kettle if needed.
Start the timer for your water bath after the water is at a rolling boil and all jars are in the canner. Process for 10 minutes (adjust for altitude if applicable) and then turn off the heat. Remove jars from the canner after 5 more minutes, and place back on the towel-covered sheet pan or counter (put down a fresh towel if you spilled while filling the jars).
Leave jars to cool slowly in a draft-free place. Do not touch rings until the jars are completely cool and sealed and do not stack jars. After jars are cooled and seals are set (I leave them overnight or up to 24 hours), check that all jars are sealed, carefully wash jars, label them, and remove rings before storing.
Sealed jars with metal lids will not flex when the seal is pressed, and the lid has a firm vacuum seal with the jar. Any jars that did not seal can be reprocessed the same day with new lids (check the jar tops again for chips and the ring for dents), or immediately refrigerated and used first.