I read today in the paper that the grapes in Napa are being harvested a week earlier than last year.   Its time to start measuring the BRIX on the grapes. Meanwhile its also time to start finishing the port from last year.   Here is the recipe I will be using.

FORTIFYING WINE

To produce a proper port we need to add distilled spirits to our wine. This process is called “fortifying” the wine. The PEARSON SQUARE is used to determine the amount of alcohol needed to fortify a wine. It is necessary to know the percentage of alcohol by volume of the wine to be fortified, also the percentage of alcohol by volume of the spirit to be used for fortification. The spirits most often used for this purpose are brandy and vodka of 40% alcohol by volume (80 proof). Convert this to alcohol by volume dividing the number proof by 2. For example 80 proof is 40%  alcohol by volume (80 ÷ 2 = 40).

A = Alcohol content of spirit to be used.
B = Alcohol content of wine to be fortified.
C = Desired alcohol content of final product.
D = C – B This is parts of fortifying spirit.
E = A – C This is parts of wine to be fortified.

Our harvest:
We have 15 gallons of wine at 15% alcohol that we want to bring up to 20%.  We are planning on using brandy at 40% (80 Proof) to fortify this wine. 

Therefore,

A = 40
B = 15
C = 20
D = 20 – 15 = 5 parts fortifying spirit
E = 40 – 20 = 20 parts of wine

Therefore for every 20 ounces of wine that we want to fortify, we need 5 ounces of
brandy to bring the final product up to 20%. This is a 4:1 ratio of wine to spirits (20 ÷
5 = 4). Each gallon of wine has 128 ounces. This means we  have: 15 x 128 = 1920 ounces of wine. Divide this number by 4 and this tells us you how much brandy we need.
1920 ÷ 4 = 480 oz  or    3.75 gallons of Brandy.

Total yeild will be 15 +3.7 gallons or roughly 19 gallons of PORT (72 liters)

5 (750l) bottles of port per gallon makes a total of 95 bottles of port!.  I need a barrel.