As has been suggested, use tomato juice or vinegar. I always use apple cider vinegar in my meats whether I am cooking in my big cast iron dutch oven on top of the stove,or in the crock pot or in the oven. The vinegar taste disapates but leaves a richness. I love tomato juice but hubby hates it so I stick with vinegar. I never have tough meat. You can also use white vinegar or red wine vinegar as well. I would never make meat or chicken without about 1/4 cup vinegar added. It is never tough.