Bentonite

[Thomas]

The best time for the first racking is right after fermentation completes.

Get yourself a Clinitest kit at the pharmacy. It is used to measure sugar in urine for diabetes, but it also works well to measure sugar in wine (because it works on a chemical color change, the kit is useful mainly for white wine, but can be adapted--I am told--for reds). Test the wine; when you have either no residual sugar (or hardly any) or when you have the desired residual sugar, should you be making a sweet wine, that is the time to rack.