This section is from the book "Preserving And Pickling", by Mary M. Wright. Also available from Amazon: Preserving and Pickling: Two Hundred Recipes for Preserves, Jellies, Jams, Marmalades, Pickles, Relishes and Other Good Things.
For pickling use young, tender beets. Wash them well, cook and peel, as usual If small, they should be left whole; if large, slice in thick slices. To make the pickling syrup, add to one pint of vinegar one cup of water, and four pounds of sugar, to each seven or eight pounds of the beets. Boil in this one dozen or more cloves and two sticks of cinnamon. Skim off all scum that may arise, then add the beets and cook about ten minutes. Remove with a strainer or fork and fill carefully into glass jars-the wide-mouthed jars are the best for most pickles. Pour the syrup over the beets in the can until overflowing, and seal while hot.