Adding sugar to the must

In order to produce a good wine, the must needs to have an appropriate quantity of sugar; this gets converted to alcohol during the fermentation process.  If the natural grape sugars are not enough, sugar needs to be added. (To explain more what this means, I plan a subsequent post about the Hydrometer!)

In the case of the white grapes, the sugar level was a little over 18 degrees, whereas the desirable level is in the region 20 to 21 degrees. With the red grapes (which apart from being a different variety of course, sat two weeks longer in the sun before picking), the sugar level was a little under 20 degrees which is good but should be a bit higher. So in both cases some sugar needs to be added.

 

A rough estimate of the quantity of white must was 500 litres. And about 150 litres of red.

The magic formula (so I'm told) is that 1kg of sugar will increase the sugar level of 100 litres by 0.7 degrees.

The white must should be raised around 2 degrees to bring it close to 21. So let's the desired increase is 2.1 degrees (3 times 0.7). And it's 500 litres (5 x 100 litres). So 15 kg (3 x 5) of sugar was added.

With the red, I was told 4kg of sugar should be added. So 150 litres will have it's sugar level raised by about 2.6 degrees, with an end result around 22 degrees.  I was told this would make a semi-sweet red.  Now my personal preference is for dry reds, but this year is for learning so I don't want to interfere until I know what I'm talking about!