This section is from the book "Save It For Winter.", by Frederick Fry Rockwell. Also available from Amazon: Save It For Winter; Modern Methods Of Canning, Dehydrating, Preserving And Storing Vegetables And Fruit For Winter Use, With Comments On The Best ... For Saving, And When And How To Grow Them.
Tomatoes are more important than any other vegetable for keeping for winter by canning. Select only solid, smooth fruit, preferably of a deep color. Pick out the smallest, most uniform in size, for canning whole. Grade for ripeness, and discard any showing the slightest sign of decay, and also those not fully ripe-the latter may be kept for a day or two and will quickly ripen up. Immerse in boiling water just long enough to loosen the skin-1/2 to 1 minute; dip in cold water and peel; remove the cores and stem ends or other hard spots, saving the juice; place in juice and bring to boil; pack hot without the addition of water; or slice or put in whole by cold-pack method in sterilized jars or enamel cans. In packing whole, cover with juice from cutting or squeezed from some fresh tomatoes; add a teaspoonful of salt to each quart can or jar. Process for 25 minutes at 212 degrees, or for 10 minutes at 10 pounds pressure.