Coffee Data Science
Starbucks, what are you even espresso’ing?
Drinking coffee for data
André Eiermann has been collecting data across the world to understand how strong coffee is in different locales. He measures this using TDS, and he convinced me to drink Starbucks for science.
Total Dissolved Solids (TDS) is measured using a refractometer, and this number combined with the output weight of the shot and the input weight of the coffee is used to determine the percentage of coffee extracted into the cup, called Extraction Yield (EY).
He asked for people for people to submit some data as he could not visit all the coffee shops, and I submitted a shot similar to this 1:1 espresso at 21% TDS.
My espresso style is very efficient and strong, and we were chatting when he mentioned he wanted to get measurement at some shops around the US. He knew I had the equipment and asked if I could collect some data.
So off to Starbucks I went, for science. This is the second time I have ordered espresso from Starbucks; the first was a disaster.
I got a single blonde shot. I don’t know how much liquid there was, but it was a short shot. I estimate around 14g given it was less than my usual 24g output.
I measured it to have 4% TDS, which is crazy low. Typically, the range should be between 7% and 12%.
4% is impressively in the wrong direction, and I’m sort of impressed how bad it is. I know Starbucks uses a superautomatic, but André shared with me some of the data he has published which shows 4% is within range of commercial espresso shops:
The shot itself wasn’t the worst, but it only score 1/10 on my taste scale, so it is by far the worst shot I have had in the past few months short of the sourdough baked beans shot.
If you like, follow me on Twitter, YouTube, and Instagram where I post videos of espresso shots on different machines and espresso related stuff. You can also find me on LinkedIn. You can also follow me on Medium and Subscribe.
Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
