Due to the massive success of Port wine in the first half of the 18th century, that led lots of grape growers out of the Douro region, to use their grapes for Port Wine production changing its quality and because of the difficulty in territorial planning, in 1756 the Prime Minister “Marques de Pombal” restricted the Douro Valley region with 335 milestones, distributed along 250.000 hec.
Making it the oldest defined and protected wine region in the world. Nowadays in the Douro Valley we have 45700 hect cultivated, from wich 33000 hect are suitable for Port Wine and 39100 grape growers.
In 1932 the Casa do Douro, an Association of vintners, they had the mission of registering all the planted plots in the Douro.
In 1948, a very important person, an Agronomist, mr. Moreira da Fonseca, used the info collected during decades as well as the data of the quantity and quality of the different sub regions.
He has created a classification method, based in three major factors: soil; weather conditions and type of plantation.
Each vine/hectare gets points based in:
Soil: schistous soil; quantity of shale; slope gradient; yield;
Weather conditions: exposure; altitude; shelter; location; pre-marked localities;
Type of plantation: grape varietals; type of planting; age of the vines;
- A – over 1200 points
- B – from 1001 to 1200
- C – from 801 to 1000
- D – from 601 to 800
- E – from 401 to 600
- F – from 201 to 400
- G – from 1 to 200
- H – from -200 to 0
- I – from -400 to -201
The Instituto dos Vinhos do Porto e do Douro, has the annual task of presenting the maximum of Port Wine to produce, according to the variation of the market, sales and Wine reserves, for instance in 2011 was 85000 barrels (85000 x 550 liters) the same as 46.750.000 liters.
The quantity of must for fortification per hectare, in 2010:
- A – 2.043 liters
- B – 2.010 liters
- C – 1.859 liters
- D – 1.818 liters
- E – 1.573 liters
- F – 684 liters
- G – 0
- H – 0
- I – 0
The Moreira da Fonseca method is a very important contribute, once that each Port and Douro Wine producer knows how many liters may produce per hectare, according to the Instituto dos Vinhos do Porto e do Douro.