The formation of a good firm sediment can be encouraged by bringing the wine into a cool place. However, if the wine has finished fermenting, a sediment should form quickly of its own accord. In any event, once the wine has cleared significantly, and you are sure the fermentation is over - rack!

Racking is simplicity itself. The jar containing yeast and sediment should have been allowed to settle, and be positioned about two feet (60 cm) above a clean, sterile jar of the same size. The air-lock and bung are removed from the top jar and a sterile siphon tube is inserted into the wine. Sucking on the open end of the tube (or the careful use of a small siphon pump) causes the tube to fill up. This end of the tube is then placed into the mouth of the lower jar and the wine is allowed to flow in, while care is taken to ensure that the upper end of the tube does not disturb the sediment. It is helpful to have a small tap on the lower end of the tube to control the rate of flow when the level of wine in the upper jar  nears the sediment: the slower the rate of flow, the less likely that any sediment will be sucked up. Most of the wine in the upper jar can be safely siphoned off the sediment by carefully tilting the jar as the liquid level nears the bottom. 

The lower jar should now be topped up: see the note on topping up and racking below. Also at this stage, a Campden Tablet should be dissolved in each gallon (4.5 litres) of wine to ensure that it keeps well. Any remaining yeast and other suspended matter will drop out of suspension fairly quickly, and a second racking should take place as soon as the wine has cleared more or less completely.

There is no reason why more rackings cannot be carried out if this seems essential; however, with a properly prepared must and careful straining, two rackings are generally enough. Remember that each time the wine is racked it is exposed to the air, with an inevitable danger of infection and oxidation. Although some authors suggest that this can be reduced by adding one Campden tablet at each racking, I do not recommend adding more than one per gallon.

Topping up and racking

Each time the wine is siphoned off the sediment, a small volume of liquid will be left in the upper jar. This produces an air-space in the lower demijohn which needs to be topped up with water or wine of similar strength and flavor to the wine you are racking. This avoids oxidation of the wine. The only exception to this rule is in the production of sherry.

At first sight, you may think that topping up with water will considerably reduce the strength of the wine. However, this is not so. If the pulp was strained off correctly when the wine was originally transferred to demijohn, the loss on racking should be so small that topping up has a negligible effect on the overall strength of the wine. If for any reason a very thick (over 1/2 inch or 1 cm) sediment forms during fermentation, the wine may be topped up after racking with another finished wine of similar type or with a mixture of vodka and water at the correct strength. A useful idea may be to make up a "neutral" wine from grape concentrate and use this for topping up.

The second (and any subsequent) racking should involve so little loss of volume that topping up with water has an insignificant effect on the strength of the wine.

THE FINISHED WINE

As a rough guide (Individual taste is more important than a set of rules), these are the expected S.G.s of finished wines:

Dry 0.980-1.000

Medium 0.995-1.005

Sweet 1.005-1.020

You will see that the S.G. of a dry wine can be less than that of water, i.e. 1.000. This because alcohol is less dense than water. Thus a mixture of alcohol and water (which is really what a wine is) will have a lower S.G. than the same volume of water. Note also that the effect of alcohol on the S.G. of a finished wine makes it impossible to calculate the weight of sugar in a finished wine by measuring its S.G. and referring to the hydrometer table.

If you wish to sweeten a dry wine to taste, you may find the following table helpful.

These figures are a useful guide if you are sweetening a dry wine to taste. However, it is important to remember that they are only a guide, and that as your palate becomes more discriminating you will be able to detect smaller amounts of sugar.

As I've already explained, the unfermentable sugar lactose may be used as a sweetening agent without any risk of refermentation; however, it is only about one-third as sweet as sucrose, so proportionately more needs to be added. Obviously lactose may be added at any stage of production, whereas sucrose must be added when the wine is perfectly clear and stable.

You should add the sugar by dissolving it in a little wine and then stirring this solution into the main bulk of the wine. A totally dry wine may be a little astringent - even dry wines need a little sugar in them!

Next: fining, filtering, and storage