A natural crystalline compound found in plants, especially those with tart characteristics such as unripe grapes. The principal acid in wine, tartaric acid is the component that promotes graceful aging and crispness of flavor. One of the by-products of tartaric acid is CREAM OF TARTAR, which is used in baking and candy-making.
I don't know about your part of the world, but in Australia it's readily available from supermarket shelves, baking section.
As for canning, heck, I've never used a water-bath in my life for jams, pickles etc. I don't even use special jars. I just recycle jars of a suitable size, those with a twist-and-pop metal lid, or a plastic screw-on lid. I find if you spoon the boiling jam directly into the jars (with an all-metal knife standing in the jar so the glass doesn't shatter), filling the jar right to the brim, then immediately put on the lid, a perfect vacuum seal will be formed once the jam is cool. Some people like to turn the jar over while the jam is cooling, and claim it makes a better seal, I've never found it necessary. I reckon if you have to use special jar-opening gadgets, insert a knife under the lid to break the seal, or get a very strong man to open the jar for you, the seal is good enough! I store my jams etc in a pantry cupboard where it's comparatively cool and dark, or in the fridge as space permits (I live in a very hot climate). Store in the fridge once opened, as you normally would. Shelf-life is measured in years. The only products I make which I keep refrigerated after putting in jars this way, are such things as Lemon Curd, which have a refrigerated shelf-life of only about 1 month (because of their egg content).
Information I've had from various other forums, books etc has revealed that water-bathing of jams and similar products is a uniquely American thing. It's up to you whether you want to do it or not. It's not difficult, and it's certainly not necessary, whatever scare-mongers might tell you!