In a small bowl whisk the mustard powder, sugar, wine, vinegar, salt and turmeric until smooth and thick. Adjust the consistency with up to 1 teaspoon warm water. It should be thick, but not pasty since it will tighten up a bit as it sits. Chill for at least one hour or up to 3 days to allow the flavors to meld. It should be very sharp and a bit sweet.
Preheat the oven to 300 degrees F.
Put the bread in the oven to warm while cooking the franks. Heat a large griddle or nonstick skillet over medium heat and add the butter. When melted, add the franks and cook, turning, until hot through and browned on the outside, about 5 minutes.
To assemble, put a frank inside a warm piece of bread and drizzle with the sweet hot mustard to taste. Top with sauerkraut.