Heidi's Favorite Apple Butter

4 lbs of good cooking apples (we use Granny Smith or Gravenstein)
1 cup apple cider vinegar
2 cups water
Sugar (about 4 cups, see cooking instructions)
Salt
2 teaspoons cinnamon
1/2 teaspoon ground cloves
1/2 teaspoon allspice
Grated rind and juice of 1 lemon

Equipment Needed
1 wide 8-quart pan (Stainless steel or copper with stainless steel lining)
A victoria strainer or food processor/blender
A large (8 cup) measuring cup pourer
6-8 8-ounce canning jars, new lids and rings.

Preparing the Fruit
If you have a victora strainer: Cut the apples into quarters, without peeling or coring them (much of the pectin is in the cores and flavor in the peels), cut out damaged parts.
Else: Core, and peal apples
First Stage of Cooking
Put them into large pot, add the vinegar and water, cover, bring to a boil, reduce heat to simmer, cook until apples are soft, about 20 minutes. Remove from heat.
Measure out the purée and add the sugar and spices
If victoria Strainer: Ladle apple mixture into strainer, and strain.
Else: Ladle apple mixture into food processor, or blender.
Measure resulting puree. Add 1/2 cup of sugar for each cup of apple pulp. Stir to dissolve sugar. Add a dash of salt, and the cinnamon, ground cloves, allspice, lemon rind and juice. Taste and adjust seasonings if necessary.
Second Stage of Cooking:
Cook uncovered in a large, wide, thick-bottomed pot (a wider pan is better as it encourgages evaporation) on medium low heat, stirring constantly to prevent burning. Scrape the bottom of the pot while you stir to make sure a crust is not forming at the bottom. This takes a LOOOOONG time to get right, several hours. slowly the butter will darken and thicken. Cook until thick and smooth when a bit is spooned onto a cold plate and allowed to cool sets up like a soft jelly.
Can according to normal directions:
Seal in boiling water bath 10 min