This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
For home-use some may prefer to have the sugar color crystallized. This is easily accomplished. Operate entirely as directed for converting the sugar or its substitutes as before, but don't pour any water into it. When the tests have proved the finish of the operation, pour the whole mass on a sheet of iron or into an iron cake-mould, when it will quickly crystallize to a porous black mass. When cold it is easily cracked to pieces or lustrous fragments, which are stored in wide-mouth bottles, closed air-tight (as air would moisten it) and kept ready for use. These fragments are easily soluble in water, and when required for use it is only necessary to cover them with water and filter the solution, which will be bright and clear.