More Numbers on Starbucks

In a previous post, I calculated that in a year, Starbucks uses around 2.916 and 2.946 billion cups in their retail stores every year. For the purpose of this post, let’s round that to 2.93 billion cups. This is something that makes your life (approaching) infinitely easier when you’re working with bounds and ranges.

Oceans of Coffee?

If you like to think about large numbers, you’re probably wondering how much liquid that represents on an aggregated level. Well, we know that drinks come in four different sizes at most stores – tall (12 fl oz), grande (16 fl oz), and venti (20 fl oz for hot drinks, 24 fl oz for cold drinks). There are also short (8 fl oz) and trenta (30 fl oz) sizes, but they aren’t available at every store.

There isn’t any good data on the distribution of drink sizes, so we’re going to have to create one that seems reasonable. Using inverse proportions (as we did in the original post) isn’t going to work here because there are two different sizes of venti, so they would be over-represented. Instead, if we assume that cold and hot drinks are purchased in equal proportions, we can average the two sizes of venti and because they belong to the same exclusive class (ie, you can’t get a hot drink in a cold venti cup) we can use this to create a proportion. The average of 20 and 24 is 22, so we can use 22 fl oz as the average size of a venti drink. Then, because we assume that smaller drinks (being of lesser cost) are purchased more often, using the inverse proportion method we calculate that the average size of a drink is 15.68 fl oz, or just shy of a grande in size.

So, 2.93 billion units at an average size of 15.68 fl oz indicates a total yearly production of 45.94 billion fl oz, or 358.90 million gallons, or 1.36 billion liters. According to Wolfram Alpha, this is 1/290th of the total volume of humans alive on Earth, 1/20th of the volume of concrete used in the construction of the Three Gorges Dam, or 1.3 times that volume of the Empire State Building.

Another way of thinking about this question is in terms of distance. A standard US one gallon milk jug is about 10.25 inches tall including the cap. Laid end to end, the yearly production of Starbucks placed into these jugs would form a line 58,071 miles or 93,440 kilometers in length. This is equal to 4.4 times the length of the Great Wall of China, and would wrap around the Earth at its equator 2.3 times. To travel from one end of this line to the other at the speed of light would take 312 milliseconds. Finally, this is roughly a quarter of the average distance from Earth to the Moon.

If you think about it in terms of the actual cups that Starbucks uses, using inverse proportions and this handy list of cup measurements, I calculate that the average height of a Starbucks drink is roughly 130mm or 5.12 inches. At 2.93 billion drinks per year, laid end to end this would form a line 236,768 miles (381,041 kilometers) in length. This is 60 times the circumference at the Earth at the equator, 99% of the average distance from Earth to the Moon.