Collards can sometimes have a slightly bitter taste. If you notice by just tasting a leaf that it is more bitter than usual, you can add a bit of baking soda to the simmering water (no more than a 1/2 of teaspoon) to help neutralize just a bit. Also the ingredients in our greens recipe help with this as well. From the sugar add to the vinegar and smoked meat, it all helps to mask some of that bitter flavor.