This question took me back to the April Fool Days that my grade school children filled the sugar container with salt and vice-versa. Not the table service containers..........the main storage bins. Unfortunatly for them, I had baked, cooked up a storm; everything all at once. We ran a business from home in those days, so I was pre-occuppied with truck drivers, telephone calls to parts houses as I cooked with the phone propped on my shoulder. They weren't to thrilled at what they saw as the first round of cookies, dinner, gravy, etc was rolling off of the stove.
But, why would the sauce be sweet? Is it a recipe you added sugar to? Or if you added wine did you let it have a chance to simmer?
Five gallons is a lot, so you my be surprised at how long it needs to cook to bring it around. Normally you would not automatically increase sugar and salt in a recipe at the same ratio as the other ingrediants.
On the other hand, if it has cooked down and condensed, some flavors maybe more intense, maybe you need to add some water and thin it down. Or some tomato juice, or tomato sauce may do the trick.
Have you tasted it with pasta? It may not be that bad.
After that the only thing I could suggest is try a couple of tablespoons
of white vinager, or red wine vinager. Add this sparingly and simmer, you my need to add more salt if using the vinagers to pull it around.