Taco Bell spent years trying to fix a huge mistake that customers hate - but it still hasn't succeeded

Taco Bell

Taco Bell is obsessed with perfecting the Quesalupa's cheese pull - but many customers are still disappointed. 

The Mexican chain has spent two years perfecting what its chief food innovation and beverage officer Liz Matthews calls "the cheese-pully thing," reports Bloomberg.

That's two years of trying to ensure that Quesalupas and other cheesey items have the same stretchy cheese elasticity when pulled apart that customers see in the brand's ads.

Perfecting the cheese pull hasn't been easy, Bloomberg reports. The Quesalupa's shell has to be fried for 90 seconds. After that, it cannot sit for more than 15 minutes, or the cheese will harden, failing to create the cheesey bridge between separate pieces.

Hollis Johnson

Taco Bell's social media team closely watches the brand's Twitter to keep an eye out for customers disappointed that their cheese pulls didn't live up to ads. If they spot a complaint, it could lead to an email reminding staff not to overcook the tortilla or allow products to sit too long after being fried.

However, a quick look at Twitter demonstrates that the chain hasn't been able to completely solve the cheese issue - no matter how closely Taco Bell monitors it.

In the past few weeks, there have been more than a dozen tweets complaining that the Quesalupa's cheese doesn't measure up to the commercials.

For comparison, here's what Taco Bell advertises a Quesalupa cheese pull should look like: 

Bloomberg notes that the cheese pull has become an indispensable part of Taco Bell's business.

"People stopped seeing cheese as an ingredient - cheese really became the center of the plate and a big deal," Matthews told Bloomberg.

However, if people are still tweeting about subpar cheese pulls, even more customers are leaving their local Taco Bells quietly annoyed about a lack of cheesiness. The chain may have the procedures in place for the perfect cheese pull, but as a chain with 6,500 locations, the execution still needs work.