Espresso is a coffee extraction process where hot water is forced through finely ground coffee at a barometric pressure of nine - which means nine times the usual pressure you feel at sea level, which translates to about 130 pounds per square inch, about 400 percent of your car tires.

Some people drink it diluted with water, an Americano, or with milk, as a latte. In modern times, some people even drink it cold. If an in vitro (cell culture) study holds up, people may even drink it to help ward off Alzheimer's disease. 

Coffee has been linked to some health benefits (1) and the popularity of stores like Starbucks in the last 30 years sent its popularity higher than ever. The mechanism behind why coffee might be beneficial are unknown, that is why it is just epidemiology, but new work can at least point in a direction. Tau proteins help stabilize neurons, which are the skeleton of brain cells and keep things moving. With some diseases, like Alzheimer's, tau has been found clumped in fibirls, so the experiments used caffeine, the phytoestrogen genistein, and the alkaloid xantheose, which is in chocolate and added to cosmetics. 

Can you identify my latte art? Neither can I. All I care about is taste. Maybe some day I will care about how much it improves my health. Credit: Hank Campbell, Science 2.0. 

Caffeine, genistein and espresso itself were found to keep tau protein problems from propagating with espresso achieving the strongest result. No propagation might mean no progression, and that would be good enough when it comes to an insidious disease like Alzheimer's.

So what does it all mean? Not much yet. In Vitro studies, like animal studies or correlation such as epidemiology, are in the exploratory pile, not the science one. No drug ever gets approved based on results in Petri dish cells. or food frequency questionnaires which lead to claims quinoa porridge might mean better health. 

But a lot of great products that have been approved started in cell cultures and the traditional science world has made very little progress in the last century, so perhaps it is time to let chemists pursue new, delicious, bioactive compounds. 


(1) Even the International Agency for Research on Cancer (IARC), a statistical correlation group in France that basically exists to link everything to cancer, pivoted due to blowback over its claims a weedkiller or hot tea may be linked to risk of cancer by claiming coffee had less of a link to cancer - the only time in their history they actually didn't attempt to create more panic.