cabbage

I used a stuffed cabbage recipe from a friend. I had eaten this stuffed cabbage and it was great. When we made it, and cooked it, the saurkraut is too sour even though cooked for a long time. We have now frozen it and hope that it will meld better after defrosting. Are there any recommendations for sweetening the dish a bit?

Thanks!

Yes we rinsed and drained the sauerkraut. Here is the recipe

STUFFED CABBAGE

Cook 1 1/4 C raw rice and set aside to cool.

Chop and sautee 2 med. size onions in butter or olive oil. Set aside to cool.

Core and steam 2 cabbage heads so leaves can be removed and stuffed. Set aside to cool.

Rinse 2 large cans of sauerkraut,.

In a large bowl mix 2 pounds of ground round with 1 pound of ground pork. Salt & pepper. Mix in rice & onions, & 2 eggs. Mix well.

Open a medium size can of tomato sauce and a large can of whole tomatoes. (I like less tomato sauce but some people like more).

In the bottom of a large roasting pan, place about 1/3 of the tomato sauce & whole tomatoes. I squash the whole tomatoes into smaller bits. Then layer on about 1/3 of the sauerkraut.

Tear off cabbage leaves & fill with a tsp - tbs of meat & roll. (Again, amount of meat is personal preference. I prefer the smaller cabbage rolls to the larger). Layer on top of sauerkraut in roasting pan. Then pour 1/3 of tomato sauce & whole tomatoes, then another layer of sauerkraut. Repeat.

Now that we may have diagnosed the problem, does anyone see a reasonably quick fix? I thought I rinsed and drained pretty well, but perhaps not sufficiently. However, are there any suggestions for fixing this when we reheat?

Thanks