I grow sauce tomatoes, roma and others. When they come in I blanch them, then run the thru a food mill. I then freeze the sauce in plastic freezer bags or cook it down into paste.
I recently tried pulling out several bags of the frozen sauce to cook down into paste, I sliced the bags in a couple of areas and let them defrost over night on a cooling rack set in a tray.
In the morning, the bags had just the solid tomato matter and all the liquid was collected in the bottom of the tray. Very cool I thought. . but then. . . the question came to mind. . . .
Am I losing any flavor or nutrients by just discarding this liquid or should it be cooked down with the solid tomato matter?