The following example was excerpted from the work of Matt Mathews

Pearson’s Square may be used for the following purposes:

1. Adding sugar syrup to increase the potential alcohol of a must
2. Sweetening a dry wine with sugar syrup
3. Fortifying a wine by adding brandy or neutral grain spirits to make port
4. Adjusting the titratable acidity of two wines by blending

Example Computation

1. Start by studying this table.

Where,
A = sugar concentration of weak juice.
B = sugar concentration of syrup.
C = target concentration of A+B mixed,
D = part of A needed to meet the target solution
E = part of B needed to meet the target solution

2. Replace the values
A = the concentration of our weak juice is 12% (12 °Brix)
B = the concentration of our syrup is 65% (65 °Brix)
C = our target concentration is 24% (24 °Brix).
D = (B–C) so 65 – 24 = 41
E = (C–A) = 24 – 12 = 12

3. Find the percentage of D and E
D+E = (41+12) = 53
percent D = 41/53 = 77 %
Percent E = 12/53 = 23 %

We need 77ml juice plus 23ml syrup to make 100ml of 24 °B must. Verify your results using a hand refractometer.