The Wine Pages: Homebrew winemaking
This is the boring bit.
All you have to do is put the demijohn in a warm place and leave it for a week. At this stage you will not have a full demijohn, so top it up with some sugary water that has a gravity of 1090.
Now leave alone for a period of time of between a couple of weeks and a couple of months. The fermentation will grind to a halt. This point is characterised by
Now rack the wine.
Racking is a dead pretentious word meaning siphon the wine into a clean demijohn, leaving the gunk (lees) at the bottom behind.
Pay close attention to the fermentation temperature
Try not to drink it whilst it is fermenting
Now move onto Clearing and finishing.