Pick ripe heirloom tomatoes. If you pick only red-ripe fruit, your end product will be prettier. If you pick them a little less ripe, the finished product will just be a little more pale. Stems tend to puncture the other tomatoes so I always harvest without stems. Wash the tomatoes and cut out the core at the stem end. Also remove any blemishes. Meanwhile, have a large pot of water heating. When it comes to a boil, immerse several tomatoes in the boiling water. You can do this with a cloth bag. (My mother used to heat a blue enamel canner half full of water. She put a gallon or so of tomatoes in an old flour sack. The sack of tomatoes went into the canner of boiling water. Mom had lots of tomatoes so this method was more efficient.) I usually just quickly drop several tomatoes directly in the water and as the skins begin to split, I pick them out with a tongs. You could use any type of strainer basket that fits into your pot of boiling water. If your tomatoes are more ripe, the skin will split quicker.
Drop the heirloom tomato in cold water and allow the fruit to cool. The skins should slip off quite easily. The skinned tomatoes are then cut and put in jars. A friend of mine enjoys squishing the fruit with her hands rather that cutting it with a knife. You can do it however you prefer in whatever size you want, as long as you have enough juice from the tomato to cover the fruit. Fill quarts or pints to 1/2″ of the top. It is recommended that you add 1 tablespoon lemon juice or 2 tablespoons vinegar to each quart to be sure that the acid content is high enough. (I have never done that and neither did my mother and we never have had trouble from it.) We do add a small teaspoon of salt to each quart. (Half the amounts for pints.)
Clean the tops of the jars. Put on the dome lids and tighten the metal rings over them. Seven quarts will fit in a standard blue enamel canner. Put your jars in first and then fill the canner with warm water that covers the jars by about one inch. Bring to a boil and boil for 45 minutes for quarts; 35 minutes for pints. Once it is boiling, you can turn it down, but be sure it continues to boil. It does not have to be a hard rolling boil. When the minutes are over, carefully remove the jars, preferably with a jar lifter. Set on the counter and allow to cool. As they cool, the lids should seal; that is, the dome lid will be pulled down with or without a pop or click sound. After they are cool, when you tap the lids, you will be able to hear a difference in the dome lid that did not pull down and therefore is not sealed. If I have one that did not seal, I put it in the fridge and use it within the next several days. The others go on the shelf for winter supply.
There is such a feeling of satisfaction as those shelves fill up in the fall. Ironically, there is also satisfaction throughout the winter as we use these precious heirloom tomatoes and empty the jars for next years bounty! Now I understand what my mother felt about this when I was a child. I know why she was willing to work out in the hot sun every summer.
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