In the US I have friends who are canning queens, filling and processing hundreds of jars of stuff (often grown in their abundant gardens) every summer. A few years ago I spent a day with one of these amazing ladies and fell in love the the process of cooking something, putting it in a jar, processing that jar, and then having homemade food on hand many months later. I can't get canning jars here so generous friends and family members have sent and brought jars and canning supplies, building me a small stash of about 50 jars, which are filled with jams, fruits, pickles, salsa, and spaghettic sauce. This week I made and canned spaghetti sauce, using a new recipe from a friend, which turned out to be my favorite spaghetti sauce I've made so far.
Step 1: Wash and quarter tomatoes, then cook for a little bit till they juice up nicely. I had about 4 big pots worth from 15 kg tomatoes.
Step 2: Drain the tomatoes in a colander, and catch all that good juice in a big bowl to either can or use for soup!! This step saves hours of simmering because the sauce is a lot thicker from the start with much of the juice already out of it.
Step 3: Run all the cooked tomatoes through a food mill, this squishes out the sauce and leaves the seeds and skins on top, which you then feed to your neighbor's cow or use for compost in that fabulous garden of yours. It took me about an hour total to do the first 3 steps with 15kg of tomatoes.
Step 4: Heat lids and rings in a small pot, and fill the canner with HOT water and jars to get them clean (no dishwasher) and ready for filling. Simmer the plain ol' tomato sauce you got from the food mill with the other yummy stuff you are adding.
Step 5: (missing this picture) Fill your hot jars with your hot spaghetti sauce, put on a hot lid and hot ring, then put them in the canner. Once you have your jars in the canner (I ended up with 6 quarts of sauce total), put the lid on the canner and bring to a boil to start timing for adequate processing and set your timer. Living at 7000 ft my canning times are a lot longer than at sea level, so this batch got the 66:66 time.
This is water bath canning, and it is a safe way to can fruits and vegetables with a pH below 4.6. Some tomatoes are slightly above this level and adding stuff like garlic, onions, and peppers affects the pH so I have a pH meter to make sure it is sufficiently acidic for safe water bath canning. This batch was 3.3, plenty acidic for a water bath. If it was too basic I could add lemon juice to acidify it. Foods with a pH above 4.6 require a pressure canner to safely preserve them.
Step 6: Carefully remove the jars from the canner and put on a towel on the counter where they won't be disturbed overnight. Listen for the music of ping ping ping as your lids seal. The next day, move your jars to a dark and cool place for storage. Occasionally I wish I was a canning jar for a few hours; just sitting in the dark and quiet, not being jostled about sounds pretty restful.