I don't know about you but I purchase my ketcup at the store. However, our last church there was a gal who made her own and let me tell you, it was fantastic. Below is a recipe from The Godey's Lady's Book Receipts and Household Hints © 1870
Tomato Catsup--Take six pounds of tomatoes, sprinkle them with salt, let them remain for a day or two, then boil them until the skins will separate easily; press them through a colander or coarse sieve, leaving the skins behind. Put into the liquor a handful of shalots, a pint of Chili vinegar, a pint of wine, salt, pepper, cloves, ginger, and allspice. Boil all together until a third is wasted, bottle it, and when it is cold cork the bottles very well. Shake it before using it. Good either for sauce or for flavoring.
Chili vinegar is a new one on me, basically you take dried chilies and a couple cups of white vinegar combine and let them mix. For a coarse sieve I'd use my grandmother's food mill. What surprises me is that in this cook book they don't give out measurements. There are several recipes that have some measurements but it seems when it comes to food items that are people's personal preferences, they (the cook book) assumes the cook knows what kind of portions to use.
In another cookbook The Home Cook Book ©1876 I found two other recipes for tomato catsup posted below. These are much better with regard to measurements.
Mrs. M. A. Beachl
Select well ripened tomatoes. Slice, cutting out defective parts. Put them over without peeling them. Boil one or two hours, or until quite soft; then strain, being careful to get all the pulp. To one gallon of tomatoes, thus strained, add four tablespoons of salt, one-half a teaspoon of red pepper, three tablespoons of mustard, two tablespoons of black pepper, one tablespoon of cinnamon, one of allspice, one of cloves. The salt, mustard, and pepper may be put at once into the tomatoes, but the dark spices should be simmered for one hour with one pint of vinegar, and then strained into the juice; add one heaping tablespoon of sugar. Bottle, and seal tightly.
Mrs. S. R. Gridley.
To one gallon of tomatoes add four tablespoons of salt, four of pepper, four of mustard, two of allspice, two of cloves, one pint of good vinegar. Boil down to half the quantity.
Well with tomatoes ripening in the garden I thought it might be fun to share how to make your own catsup. Enjoy!