Water

water is the most important constituent of wine (see wine composition) and access to reliable supplies of good-quality water, particularly for irrigation, is becoming a pressing problem for an increasing number of wine producers, particularly in inland Australia and much of California—not least because of climate change, drought, and problems associated with salinity.

soil water, the product of rainfall and/or irrigation, is a prerequisite for vine growth and survival. photosynthesis, without which grapes would never ripen, depends on water being available (which is why ripening stops if water stress is too severe). Water in the form of well-timed rain can also be useful in dusting off grapes immediately prior to harvest.