If your applesauce isn’t still hot, you need to heat it back up so that you can hot pack it into jars. Return the applesauce to a rolling boil.
While you wait, sanitize your jars, lids, and bands. You can do this in the dishwasher on the sanitize cycle or even just in a sink filled with hot water. They should be hot and sterilized when you’re ready to start loading applesauce!
Fill the jars, allowing about half an inch of headspace to remain. While you are filling the jars, you can fill your canner with water. The amount of water you need will vary depending on the type and size of canner you have - but keep in mind there will need to be enough water to cover the top of the jars (so the amount of water will also vary depending on whether you are canning pints or quarts).
Carefully remove any and all air bubbles. This can help prevent any oxidation during and after canning.This is especially important for applesauce, as there can be a lot of them. Wipe the rims of the jars down to remove any lingering food particles.
Put the lids on the jars and twist the bands on until they are “fingertip tight” - this means tightening with just your fingertips rather than using your entire hand to seal the jar.
Load the jars into the canner rack. Try not to let them touch.
Water bath process for 20 minutes for pints, 30 minutes for quarts.
Don’t start the timer until the water is boiling! You may find that the water takes longer to get back up to a boil after you’ve loaded the jars (but loading only hot jars into the canner can help reduce this effect). Either way, the 20-30 minutes starts only after you’ve achieved a rolling boil.
When the jars are done, you can leave them in the canner to cool down. If you have additional jars that need to be canned, remove them with your jar lifter or set of tongs (you may want to wear oven mitts so you don’t get steam burns on your hand from inside the hot canner).
Place the hot jars on a dish towel to cool. Make sure the jars are out of the direct path of a breeze or draft, as this can cause them to crack. Do not flip them upside down. As the jars cool, you may hear quiet little popping sounds. Don’t be alarmed! This is simply the jars sealing.
Let the jars cool for 12-24 hours. Check to make sure the lids have sealed - if they haven’t, you should either eat the applesauce right away, refrigerate it, or freeze it. You can also attempt to do it once more.
If the jars are good to go, put them in storage. They should be stored out of direct heat and sunlight, ideally in a cool, dark location like a basement or root cellar.