This specific winery is the one listed in the suppliers list of the book The Liver and Gallbladder Miracle Cleanse by Andreas Moritz , to buy it from. The book states, "All wineries use malic acid to produce wine" and "food-grade malic acid is very cheap and can be purchased over the internet." I've just checked the Presque site and that "Winemaking only" legend wasn't there when I purchased mine but the pictured jar and label shown are still identical to the one I bought. The book recommends to use only the powder form because it's purer than capsules, which are usually mixed with magnesium. FG on the jar label stands for "Food grade" but I don't know what it means. It has to be diluted in water, half a teaspoon in a big glass of water, twice a day is the amount recommended. Now, it is acidic, but adding more water tones it down and that's what I do that but as for people with gastric or bowel problems... I guess everything acidic will pose problems and I've had my share of bowel trouble, in fact now I've paused Liver Flushing for that very reason. I used to use it simultaneously with the apple juice and most of the time the malic acid did indeed feel milder and easier to drink than the juice so, yes, it would be good to give it a try. However I'm not sure the amount is correct. In a post here at Curezone the author was telling someone to have two of those big glasses, but other posts had him saying four glasses !!! : 8 oz. x4 = 32 oz. So I guess I've been wrong aiming for just 2 glasses and having 4 might not be easy. I wonder what amount people are using. But another alternative in the book for people who can't use apple juice is cranberry juice. It contains much malic acid, diluted in the same amount of water. (4 oz. in 4 oz. of water, 4 times per day). I guess again it has to be the pure kind, the health food store kind.
Yet another alternative is apple cider vinegar, 1 to 2 tablespoons in a glass of water, 4 servings per day, but I found that to be even more acidic than malic acid.