People are creatures of habit when it comes to Starbucks.

They often order the same thing, the same way--often at the same time every day.

Actually, so is Starbucks--a creature of habit, that is. Because when you can drive predictable revenue to the tune of $22 billion a year, you don't make changes lightly.

That's why announcements like the one the company unveiled yesterday can be unsettling. It means making a big change to something they haven't touched in more than 30 years.

Howard Schultz's trip to Italy

I'm talking about espresso, which accounts for 25 percent of all Starbucks orders. 

The Seattle based chain first started selling the tiny-serving beverage in 1984. This was after CEO Howard Schultz went on a tour of Italian coffee houses. 

"We didn't plan any pre-opening marketing blitz, and didn't even put up a sign announcing Now Serving Espresso. We decided to just open our doors and see what happened," Schultz wrote in his 1997 book, Pour Your Heart Into It.

Most customers had never even heard of the Italian drinks that were on the first menu, but these early baristas encouraged them to give them a try.

"I watched several people take their first sip. As I had, most opened their eyes wide, responding first to the unaccustomed burst of intense flavor," Schultz wrote. "They hesitated, then sipped again, savoring the sweet warmth of the milk. I saw smiles as the full richness of the drink filled their mouths."

Within a few weeks, the baristas could not make the beverages fast enough, and lines began spilling out the door.

"From the minute we opened, this much was clear to me: Starbucks had entered a different business," Schultz said. "There could be no turning back."

An attractive blonde

Starbucks didn't mess with success. It continued to sell the same, darkly roasted coffee for decades. Until this week, that is, when the coffee giant unveiled a new, lighter espresso in its U.S. stores: Starbucks Blonde Espresso.

The new variety has been a hit in Canada for a while. Apparently, Starbucks uses our neighbor to the north as a test market.

The difference between the two espresso varieties? 

"With our signature Starbucks Espresso Roast, the caramelly roast comes through in the beverage while Blonde Espresso is a sweeter, gentler flavor," said Anthony Carroll of Starbucks Coffee team, who developed the new blend. 

Seems like a small difference--and a big change.