Wash the meat and pat it dry with kitchen paper. Put it in a glass, plastic or ceramic dish (no metal!) with a cover. The dish should be only slightly larger than the joint. Bring the wine, vinegar, bay leaf, cloves, peppercorns and juniper berries to a boil in a small saucepan. Cool entirely before pouring it over the meat. Cover and marinate in a cool place for 3 to 4 days, turning the meat once every day.
Remove the beef from the marinade, drain and pat it dry with kitchen paper. Reserve the marinade. Rub the beef with salt and pepper. Heat the clarified butter in a large saucepan and brown the meat from all sides.
Take the beef out of the saucepan and sauté the onion, turnip, celery and carrot. Transfer the meat back to the saucepan and arrange the vegetables around it. Add 1/4 of the marinade, the raisins and pumpernickel. Reduce the heat, cover and simmer for 1 1/2 to 2 hours, or until the meat is very tender. Check for liquid frequently to be sure that the beef is cooking in enough liquid but not entirely immersed in liquid. Gradually add the rest of the marinade and 225-350ml water, or as needed.
Take the beef out of the saucepan and keep it warm. Remove the bay leaf and puree the vegetables with the liquid. Add cream, milk and sugar. Taste for sourness; if the gravy is too sour, add a little more sugar or milk. Simmer the gravy until it thickens. Slice the beef and pour the hot gravy over it. Serve at once.
For more information:
My German regional cookbook, Spoonfuls of Germany, has many more German recipes and stories about German cuisine. Visit my blog for more information.