Port wine grapes grow in extraordinarily rugged vineyards. Most Douro Valley hillsides are very steep and rocky. Under thin topsoil is a formation called schist, a coarse and hard rock of different minerals that splits into layers the way shale does.

Preparing land for vineyards in the Douro Valley is a herculean task. Terrace walls line the steepest hills that may rise 60 feet (20 meters) or more. These walls are made of rocks piled by hand piece by piece to create flat areas for planting and prevent erosion during the heavy winter rains.

Some gentler slopes are planted in patamares, low terraces that stand without supporting walls of rock. Other hills have rows of grape vines in vertical plantings that run down the slope rather than across it.

Planting new vines itself is also a challenge. Schist is so hard, that growers often use dynamite to give the plants a good start. They dig into the rock with a steel rod. Place the dynamite and stand back. The charge has to split the rock to get the roots started without cracking the terrace wall.
Once established, a vineyard may produce grapes for many many years and the vine roots will grow deep into the layered rock.

Let's not forget, however, that port wine is very tasty on its own and can be enjoyed at any occasion. It can also be used to make a cool refreshing drink for a warm summer's day calledport splash, a blend of half white port, half tonic water, ice and a touch of lemon juice and peel.