Fermentation Sugar Level Alcohol Etc..

John, The best way is to work out what your starting SG needs to be to achieve a given abv. That will then ferment to dryness below 1.000. and you will have the abv you want.

If you then want to sweeten the wine you must add potassium sorbate to inhibit refermentation. ( the sorbate is a sort of chemical condom that prevents the yeast reproducing!). If you like your wines dry, as I do, then there is no need to add sorbate. It is considered by some people that sorbate detracts from the flavour of the wine. I haven't used sorbate in years.

If you can, it is easier to plan ahead and just add the sugar that is needed for the alcohol level that you want. Let it ferment dry and clear. Then stabilize it with sorbate and sulfite and sweeten it to the level you want.

Stopping a fermenting wine is not easy. Sorbate will not stop a ferment. It will prevent it from restarting. One method is to put it in a fridge or freezer for a week or two to stop it. Then rack it off the sediment and stabilize it and hope it does not restart.

When do you rack and put it in the fridge? You need a hydrometer. If you start with a hydrometer reading of 16% (or the equivalent in SG or Brix) and you only want 11%, then when it drops to 5% you need to stop it. In fact I would try to stop it a little before that, maybe 5.5 or 6% figuring that it will not stop instantly.

Ray