Checking wine for dryness; chaptalising wine to the right body;
ensuring that wine isnot too dry, which gives poor flavour, incorrect
balance, & shorter shelf life
Basic facts: Wine comprises extract, alcohol, water
and residual sugars.
Alcohol is formed from the fermentation of sugar.
These components must be in balance. 2.7 grammes of sugar gives a reading
of 1 degree on the hydrometer in 1 litre of wine.
Measure the finished wine when it has cleared. With storage it will become
about 2 degrees drier. A wine that has fermented too far is too dry and sugar
must be added (chaptalisation), otherwise the balance, flavour and body will suffer.
Flavour in a wine that is too dry can be good but is improved enormously by chaptalisation.
The body, flavour, and aroma are enhanced.
When wine ferments out, becoming too dry, it has to be chaptalised.
Chaptalisation is calculated thus: the hydrometer reading of the wine to
be sweetened minus 1000 x 2.7 grammes of sugar x litres wine = for example
(a strong wine) 20 hydrometer degrees x 2,7 grammes sugar x 20 litres of
wine = 1080 grammes of sugar. Grape juice makes chaptalising easy,
particularly with light wines (3 millilitres/litre gives 1 hydrometer degree).
2 decilitres of grape juice does not affect the dryness but greatly improves
the flavour and keeping quality of the wine.
1 litre water = 1 kg (1 000 grammes)
1 litre alcohol = 800 grammes
10% alcohol/water – mixture
100 ml alcohol x weight 0.8 = 80 grammes
900 ml water = 900 grammes
980 grammes is 20 grammes less than 1 kg = minus 20 hydrometer (with Oechslescale) degrees