I have a recipe for home-made tomato paste that I want to try. It says to store in glass jars, but do I have to actually can it, or can I recycle a jar from a store-bought product?
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Diana B is a trusted home cook.
Does the recipe say it's canning-safe? Usually tomato-based recipes would be acid enough to can safely, although given the variability in acidity from one variety to another, it might be safer to add some lemon juice or citric acid to be sure. However, since most recipes that use tomato paste only call for a small quantity, I'd be more inclined to put one- or two-tablespoon quantities in the compartments of an ice cube tray, freeze, then pop the cubes out and keep in a freezer Ziplock bag. If you do decide to can your tomato paste, I would not recommend you recycle a jar from a store-bought product. Commercial canning facilities are able to process their products safely using jars that would not necessarily stand up to home water-bath canning, and given the work you must go to to make home-made tomato paste, it would be tragic if a jar broke in the canning kettle (not that the major distributor of canning jars makes such a great product any more since it became a near-monopoly in the field...but this is another beef altogether).
I would freeze it in an ice cube tray, then store the cubes in a bag in the freezer. It's not the acidity I would worry about for canning as much as the density. Something as dense as tomato paste is almost impossible to can at home because the mixture is so dense that the heat can't penetrate to the center of the paste. Freezing will be your best bet.
Dollop on a cookie sheet covered with was paper or foil, when frozen put into freezer safe container and use from freezer as needed.
I make tomato sauce and tomato paste every year. Petitbleu and Judy are right on about why freeze and how to freeze tomato paste. And you don't want large containers of it. Now if you mean tomato sauce, and the recipe is approved for canning, you can water bath can using only jars approved for canning, with new lids and in an approved canner. Hope this helps.
The recipe doesn't specify, but I will give freezing a try. Thanks for all of your help!