Dark Fluid Oozing out of Sparerib Bones

I bought some frozen st louis pre-cut spareribs from the local grocery store who had them on sale for the summer holiday (I asked for fully-frozen packages in the back). I am about 90 minutes into the cook and they are oozing dark liquid from one end of the bones, which is something I haven't seen before with fresh spareribs (see photo).

This is an experiment, trying a couple of different rubs on two halves today. Any idea what this is? I am guessing that this is marrow (but I do not know), and maybe it because they froze them after they cut them to st louis style? Someone else guessed that this might be a sign that they were frozen and thawed and refrozen. Should I just chuck them?

SmokinJohn said:

It's marrow. I had two racks like this over the weekend. Falling off the bone tender.....keep them

Click to expand...

Thanks, the marrow stopped leaking, and they have been in for 3.5 hours now. I just put them in foil, and they are looking/smelling mighty good.

I went to Costco while cooking and looked at their pre-cooked st louis spareribs (without sauce), and a third of the packages had dark areas like this near the cut part of the bone, although I would hope that those are not frozen before being cooked, but maybe they are. Nevertheless, I picked some up to try, but at $6.99 per pound, that is four times as much as I paid for these. I am heading out to the lake for fourth of july, and the boat has a grill on it, so I thought I would try them.