Crazy Images
Adding sugar to increase alcohol. Chaptalization
azucarado vinos azucar

Calculate how much sugar to add to increase the alcohol in wine

You have 150 litres of must
At the moment your must has a potential alcohol volume of 5 %
You would like your finished wine to be 13.5 % alcohol.

To do that you have to add 24.23 kilos of sugar to the must.

BTW: That is 53.42 pounds

If you are interested in beer or winemaking a refractometer is a very useful piece of equipment. They cost about $25.