hey guys. new to diy. I have made a couple decent mixes so far but not what I am looking for yet. I am trying to add a little more tartness to my juice and am not having any luck. my primary ingredients are tfa ripe strawberry and wild blueberry, along with some cream and custards and cheesecakes, depending on the sample batch I am making. I have made some decent ones but they all lack the tartness I am looking for. is there something I can add? or a good fruit or berry that naturally has it? I tried some malic acid and while I did improve the flavor, it wasn't really what I was going for. any help is appreciated thanks