I've read a whole bunch on making cider and am about to make my first batch. I know there are various opinions on using Campden tablets and potassium metabisulphite in general, but assuming I'm deadset on using it, my question is simply on quantities:
> A lot of sources say use one 12-grain tablet per gallon of must to kill yeast, bacteria etc., which should give 50ppm SO2. Now, the LD Carlson brand Campden tablets I have say they contatin 550 mg potassium metabisulphite, which is really 8.5 grains. And other sources say that it should be 0.44 grams, which is 440 mg and 6.8 grains. Further, the label says it'll give 150ppm SO2. In simple math this means that these pills are either 40% stronger or 300% stronger than what my books are telling me a Campden tablet should be.
LD Carlson seems to be a common brand that would comform to whatever standard the industry had agreed upon.
Can anyone help clear this up?
(Then of course you get into funny business depending on your pH level, but I'll deal with that later.)