Coffee or Tea?

Coffee drinkers in the United States consume approximately 400 million cups of coffee per day.  Roughly 1.46 billion cups of coffee per year at the average rate of 1.3 cups per person per day.  Assuming the global rate is 50% of the U.S. per capita consumption - - the global consumption totals 3.9 billion cups of coffee per day. 

Coffee requires about 37 gallons of water per cup from the high plateaus of Kenya to the counters of Starbucks - - water for production, processing, and milling.  Coffee requires about the same amount of water as tea to grow, but it ranks far higher in virtual water consumption because of the lower yield of end product per acre (tea requires nine gallons of water per cup).  Adding your favorite dairy product to your cup of morning coffee ups your water consumption - - one glass of milk requires 53 gallons of water.

Starbucks has a series of energy reduction and water consumption goals that one should applaud them for.  They seem on the surface to take the conceptual notion of sustainable seriously.  Under water, they have a goal to "Reduce water consumption by 25% in our company-owned stores."  Looking at the 2008-2009 results, water consumption declined 4.1% (From 24.4 gallons/square foot/store/month to 23.4 gallons/square foot/store/month - - the store portion of the unit provides equivalence for increases and decreases in store numbers).  With 5,000 stores as an estimate @ 1,000 square feet per store equals a savings of five million gallons per month.  An impressive number.

Assume that Starbucks has just 5% of the 400 million cups of coffee per day U.S. market.  This is 600 million cups of coffee per month requiring 22 billion gallons of water (at the 37 gallons of water per cup rate).  Starbucks five million gallons per month savings is roughly 0.0227% of the total coffee life-cycle water requirements.

Saving water is saving water, however the context is certainly important along with a clear and transparent view of the total production system.  Sustainability starts with a definition of the particular system boundaries and a life-cycle assessment.  None of this makes drinking coffee a bad choice: More important than any product's virtual water total is whether the region it comes from has sustainable water to grow the crop.  Starbucks is importing not only coffee, but also 22 billion gallons of water per month.