Comment by 1_over_n

"Funding

This study has been supported by Tchibo GmbH, Hamburg, Germany."

Tchibo is a German chain of coffee retailers and cafés known for its range of non-coffee products that change weekly.

https://en.wikipedia.org/wiki/Tchibo

Number of locations 700 shops (Germany) 300 (rest of world)

They might want to make some in-store claims about Dark Roast...