Water Bath Canning
Beginning in 1917, water bath canning was the only recommended method suitable for canning high-acid foods.
In water bath canning, jars are filled and lids securely, but loosely, affixed before being placed in the canner.
(1) Support the jars on a perforated platform sufficiently to permit the circulation of water under and around the jars.
(2) Have the water cover the top of the jars by at least 1 inch.
(3) Count time as soon as the water begins to boil vigorously.
(4) Remove the jars from the water and tighten the covers as soon as time is up.
--Benson, O. H. (1917, June). Home canning by the one-period cold-pack method: Taught to canning club members in the northern and western states. United States Department of Agriculture: Farmers' Bulletin, 839. Retrieved from https://archive.org/details/CAT87202739