Place the beans in a 6-quart soup pot, add 3 cups of cold water, cover and bring to a boil. Turn off the heat and let sit for 1 hour. In a frying pan, add the lard and brown the pork. Add the garlic and onion; saute until the onion is tender. Drain the beans and return them to the pot. Add the pork mixture, beef stock and paprika to the beans. Cover and simmer for 1 hour until the beans are tender. Using a slotted spoon, remove about 3/4 of the beans to a food processor or blender. Add about 1-1/2 cups of the stock left in the pot to the beans and puree. Return to the pot, adding the sauerkraut. Cover and simmer for 1 hour until the kraut is very tender. Add the salt and pepper, being generous with the pepper. Serve in bowls with a dollop of sour cream.