When your wine is ready it is not obvious that it is as sweet as you want it to be. Fermentation will normally continue untill all sugar is used up and this will produce a dry wine.

If you want to make a medium to sweet wine you may need to sweeten it. Your wine kit instruction will sometimes contain typical values for the different wines in the range. Here are some guidelines:

Dry table wine : 997 - 1000

Medium table wine : 1000 - 1002

Sweet table wine : 1002 - 1005

Dessert wine : 1010 - 1020

The best way to find out is to experiment on a small sample but to save some time and trouble you can head straight for the lower end of the intervals above if your wine is much dryer.

WARNING: If you add too much sugar, there is no way back (well, there are some tricks but you are better off not overdoing it)

Here's the formula you need:

1 unit increase on your hydrometer = 2.5 g of sugar added to 1 litre

Example:

If your Vermouth ended up at 996 it is definitely too dry. Start by moving it up to 1010 and from there add a little sugar at the time until it is perfect.

From 996 to 1010 is 14 units. Assuming you have about 20 litres, you will need to add 20 x 2.5 g of sugar for every unit you want to increase.

The addition in this case is then: 14 x 20 x 2.5 = 700 g.

In step 2 where you increase in small steps - try 1 unit at the time. The additions are then 1 x 20 x 2.5 = 50 g. Remember to wait a little between each addition since the sweetness sometimes comes with a little delay.