Global Dynamics of the Wine Industry, Stanford Graduate School of Business, Winter Quarter 2017

This week, through our midterm projects, we are learning about some exciting new and emerging wine growing areas distributed across the globe. As this exercise proves, grapes can be grown in many different environments. It made me curious to explore where on earth one cannot or should not grow wine grapes. The key elements needed to grow wine grapes are:

• adequate sunshine; sunshine is the most important element in growing wine grapes. Sunshine powers photosynthesis which is necessary for vine, leaf and berry growth. However, too much sun exposure can either burn the grapes or produce grapes in which all acid gets turns to sugar, resulting in a very unbalanced wine. Grapes can grow in relatively cold climates as long as they do not experience prolonged below-freezing temperatures. In northern grape growing regions, wines must be planted such that they get maximum sun exposure to ensure a long enough growing season for the grapes to ripen. 
• temperature variation; grape vines typically need a period of cooler temperatures so that they can go dormant and 'rest.' During dormancy, the vines store energy to promote the shooting of even and consistent buds when warmer temperatures return.
• moisture; vines need water to grow. Vines are more tolerant of drier climates than of climates with too much rain. In dry climates, water can be supplied through irrigation (although the use of irrigation is prohibited in some regions; Europe, for example). In wetter climates grapes can rot, develop fungal infections or suffer from other diseases like Pierce's disease ( a bacterial infection of the vines). For example, Pierce's disease makes growing vitis vinifiera grapes in the Southeastern US very difficult if not impossible. Climates characterized by heavy rainfall are unsuitable.
• soil is also an important consideration but wine grapes grow well in a variety of different soil types, as long as they are well drained. Interestingly, most viticulturists prefer soil which isn't too fertile since they like the vines to struggle and put down deep roots.

The ideal grape growing region is between 30 to 50 degrees latitude in both hemispheres, as shown on this map.

Thus, in short, areas not in the 30-50 degree latitude region in the northern or southern hemispheres are not suitable for growing wine grapes, either because they are too hot or too cold. Second, even areas within the band with little sunlight (think Seattle) are not ideal. Third, areas in the 30-50 band that have heavy rainfall, don't drain well, or are arid without the possibility of irrigation are also not suitable. Those conditions exclude large parts of the globe but luckily there are many regions where vitis vinifiera grows just fine, as we learned this week.