When it comes to pressure canning, is there a "golden rule" or standard for modifying recipe pressure settings or processing times when you want to change the quantity of jars used?
For instance, I am interested in cooking and canning this Split Pea and Ham Soup recipe.
Unfortunately, the recipe only makes 2 quart jars. I have a Presto 23-quart canner that can fit more than 2, and so — if possible — I would like to scale the recipe up to cook enough soup for 4 or maybe 5 quart jars worth.
But if I stuff 4 or 5 quart jars into the canner, does the pressure setting for this recipe (10 PSI) or the cook time (90 minutes) change? If so, what's the general rule for figuring these types of modifications out?