CASS, happy to post about chocolate For a recipe that has a means of easily adding or subtracting sugar, it goes like this:
chocolate liquor % needed: 53%
chocolate liquor % sitting in my pantry: 72%
If the recipe calls for 200g of chocolate, that means that it needs 53% of that amount in chocolate liquor and the rest in sugar.
chocolate liquor needed 0.53 x 200 = 106g, and simplifying and assuming the rest is sugar, 200-106 = 94g So the recipe calls for 106g of chocolate liquor and 94g of sugar.
Next I find the amount of 72% chocolate that will give me the required 106g of chocolate liquor.
106 / 0.72 = 147g, so 147g is the right amount of 72% chocolate to use.
To correct the sugar content, first find the amount of sugar in the 147g of 72% chocolate.
(1 - 0.72) x 147 = 41g
From the first step, above, we know that the recipe calls for 94g of sugar, and we have 41g, so the difference needs to be added to the recipe along with the rest of the sugar, 94 - 41 = 53g
To sum up, if a recipe calls for 200g of 53% chocolate, you can substitute 147g of 72% chocolate plus 53g of sugar.
Hope that is clear and makes sense