As a result, he set out on a quest to make sure that each and every coffee he makes never varies from his winning formula.
In a written statement, Dr Hendon said: 'One day you might have a good cup of coffee and the next day you might not.
"From a scientific perspective, it has always puzzled me why we couldn't do the same thing twice.
"My research looks at every variable that goes into making espresso coffee, from grinding and packing the ground coffee, to water pressure and mineral chemistry.
"If every single café in America were to implement the procedure, it would save the U.S. $300 million (£214 million) a year by reducing the amount of coffee beans used to make espresso, while improving reproducibility."
Looking first at the water used, they concluded that 'hard' water with a high amount of magnesium and calcium causes coffee to have a stronger flavour than "soft" water.
This is because compounds like caffeine stick to magnesium during the brewing process.
Hard water can also have high amounts of bicarbonate, which causes coffee to have a more bitter flavour.
They also confirmed that the storage of coffee beans was important for taste.
Fresh beans stored in the fridge came out on top here because freshly roasted coffee contains carbon dioxide that easily evaporates.
When these gases leave the beans, it produces a less flavourful cup of coffee.
Then they turned their attention to the grinding process.
Dr Hendon said: 'There is a point in grinding coffee beans when you make too many small particles, which stick together and result in reduced extractions.
"Although smaller particles mean a greater surface area, which should result in consistently tasty espresso, there is a critical point at which smaller isn't better.
"The grinders used can have a significant impact on the flavour of the resulting cup of coffee."
Size of the ground beans was not the only factor to take into account when considering grinding.
To make a truly great cup of coffee, how the water comes into contact with the ground beans is crucial.
Dr Hendon added: 'When extracting the espresso, the water should come into contact with the coffee grounds uniformly.
"Passing water through the grounds in a systematic manner would ensure that all of the grounds come in contact with water equally.
"In comparison, with a traditional drip-brew coffee pot, the water drips mainly through the centre of the grounds while the grounds on the outside have little contact with water."
Using these revelations from his scientific process, Dr Hendon then put it into practice with a team of baristas.
They found that by altering the ground size and brew ratio they not only produced consistently good coffee but saved on the amount of beans used.
He added: "By predetermining the coffee-to-water ratio, as well as the water pressure, the maximum extraction can be systematically determined.
"The barista can then iteratively improve their espresso reproducibility, while reducing waste coffee mass."
He has now turned his attention to improving the process even more by looking at grinding temperatures.
He has found that cooled coffee beans grind more uniformly and is working on the perfect ratios and ground size.
Dr Hendon has presented his findings to the American Chemical Society.
