by Rachel Saunders of BLUE CHAIR FRUIT If you're making jam, marmalade or chutney, you can skip the steamy water bath canning process and use the heat of the oven to sterilize and seal your jars.
Note: this method is not safe for other types of preserved foods.
HOW TO STERILIZE AND SEAL YOUR JARS USING THE OVEN METHOD
First, be sure your jars are clean. Place the clean jars upright with an equal number of clean, unused lids on a baking sheet or in a pre-heated 250°F oven. They should reman in the oven for a minimum of 30 minutes to ensure that they are heated through.
When your jam is done cooking and you are ready to fill your jars, remove them from the oven, keeping the oven at 250°F. Fill your jars, leaving 1/4 inch of room at the top. Before lidding each jar, wipe its rim with a clean, damp cloth. Lid the fitted jars, being careful to screw the lids on just until they are snug.
Replace the filled jars in the oven for 15 minutes or so to ensure they are completely sterilized. Remove the jars from the oven and place them 1 inch apart on a drying rack to set overnight at room temperature. Do not jiggle or disturb them during this time, as this may disrupt their ability to set correctly.
Before putting your preserves away, be sure to feel the top of each lid to verify that it has sealed; it should be curving in very slightly in the middle. If any jars have not sealed, put them in the refrigerator for safekeeping and enjoy within a few months.