Tim Harford (The Undercover Economist) solves the mystery of the elusive short cappuccino in Starbucks Economics:
The problem with large cappuccinos is that it’s impossible to make the fine-bubbled milk froth (“microfoam,” in the lingo) in large quantities, no matter how skilled the barista. A 20-ounce cappuccino is an oxymoron. Having sampled the short cappuccino in a number of Starbucks across the world, I can confirm that it is a better drink than the buckets of warm milk—topped with a veneer of froth—that the coffee chain advertises on its menus.This secret cappuccino is cheaper, too—at my local Starbucks, $2.35 instead of $2.65. But why does this cheaper, better drink—along with its sisters, the short latte and the short coffee—languish unadvertised? The official line from Starbucks is that there is no room on the menu board, although this doesn’t explain why the short cappuccino is also unmentioned on the comprehensive Starbucks Web site, nor why the baristas will serve you in a whisper rather than the usual practice of singing your order to the heavens.
Economics has the answer: This is the Starbucks way of sidestepping a painful dilemma over how high to set prices.
It’s simple price discrimination.