Chemists with experience as baristas may soon find they have a technical advantage over their non-coffee-slinging colleagues, as espresso machines join the lineup of laboratory equipment. Espresso machines work by passing near-boiling water through finely ground coffee beans, under pressure, to yield a coffee concentrated with flavors that other processes cannot duplicate. When Jason A. Smith, a lecturer at Australia’s University of Tasmania, bought a new espresso machine for his home, he wondered whether his old one could find a new purpose in the lab extracting natural products.
“Making coffee with an espresso machine is all about extracting flavor and aroma compounds, and really it is not a major jump to consider using it for other plant material,” Smith says.
The graduate student tasked with repurposing the machine, Jeremy Just, had no reservations using it for his research. He has, however, developed something of a reputation around the chemistry department for this work. “It has definitely been remarked more than once that I am undertaking a Ph.D. in making a good coffee,” Just says.
Smith, Just, Alex C. Bissember, and colleagues recently published the espresso method for the pressurized hot water extraction of natural products (Org. Lett. 2015, DOI: 10.1021/acs.orglett.5b00936). The researchers used the method to extract shikimic acid from ground star anise.
Bissember tells Newscripts that there has been a lot of interest in this new method from other laboratories. Additionally, the extraction method has been incorporated into the undergraduate laboratories at Tasmania for the extraction and isolation of eugenol from cloves, Bissember says. “It is much quicker, and the results are outstanding.”
Reflecting on the success of this method, Smith says, “It was interesting, and perhaps not surprising, that the conditions and parameters to making a good coffee are very similar to those that give a good extraction of metabolites from plant materials.”
In another nontraditional spin on beverage making, spherification—a method that encapsulates liquids in an edible membrane—is now being applied to produce mouthwatering cocktails. For those unfamiliar with the history of this molecular gastronomy technique, spherification came into prominence in the 2000s when chef Ferran Adrià started making spherified avant-garde cuisine at his world-famous restaurant elBulli, in Roses, Spain. Although the restaurant no longer exists, the technique is used by many practitioners of modernist cuisine worldwide.
To experience this molecular gastronomy firsthand, the Newscripts gang met with chef Miguel Angel Marcelino from the Washington, D.C., cocktail lab Barmini, where he prepared the restaurant’s famous carbonated mojito spheres.
The cocktail-concocting process takes well over an hour to complete and begins with the preparation of the mojito mix—a solution of xanthan gum, ascorbic acid, calcium gluconate, rum, lime, and sugar. Marcelino gently pours spoonfuls of the mojito mix into a solution of sodium alginate, which forms an edible membrane around the mojito drops on contact. After a few minutes, the mojito spheres are placed in a whip canister loaded with a solution of CO2. Over the course of an hour, the CO2 will penetrate the skin of the mojito spheres and yield a delicate and delectable cocktail experience.
Anyone who wants to re-create this edible cocktail in their own kitchen can purchase spherification kits from Amazon for about $20.