7 gram/litter , test with a ta test kit , I brought mine up to 6 gram/liter with acid blend, and the last 10 gram/liter with tartaric. Now I will tell you that there is a fellow around corner that makes wine profesionally to sell, he told me that I was low and should bring it up to 8 gram per litter. But I like mine I dont think I will add anymore acid, also most recipe will get you verry close usually a little to the low side. When you bottle it will still taste tart and will fall off over time. I just get close and age in carboy, when ready to bottle try to get acid right on. There are some who do it strictly by taste.