While the fingerprinting method is similar to magnetic resonance imaging (MRI), NMR preceded its better-known cousin by 30 years; the first NMR machine was developed by Felix Bloch and Edward Purcell in 1945. MRI, in turn, was developed from NMR in the 1970s and made commercially available in the 1980s.
Where MRI uses a magnetic field and radio waves to assemble anatomical images, NMR uses a magnetic field to measure nuclear spins, which are affected by electromagnetic radiation. The spectrometer presents the absorbed frequencies as a series of peaks on a graph, which reveal the chemical environment of atoms in the sample. When Ellis and McIntosh interpret the results, they match these peaks to their gin spectra to “build” the structure of molecules present.
“The spectrum is a lot more complicated than it would be if you had a simple organic molecule as pure compound, and identifying the fingerprints of all of those different molecules is really the main challenge. But we’ve shown it works,” says Ellis. “It’s now quite a well-accepted technique for looking at complex mixtures, including food and drink.”
The researchers can even distinguish between molecules with the same atomic makeup. Terpenes, the chemical characterizers of gin, have the same generic chemical formula (C5H8) but offer entirely different flavors, aromas, and textures. Limonene tastes of orange, for example, while myrcene is sweet and spicy.
Knowing exactly what’s in a gin matters more now, as the industry continues to grow and counterfeits and copies look to cash in. The premium sector is set to be worth around $1.4 billion by 2030, and establishing provenance and authentication will be essential to distillers hoping to protect their products and prove to well-heeled customers that they’ve used those rare and expensive ingredients.
The thriving market has also translated into a rapidly increasing demand for juniper berries, just as traditional juniper suppliers are struggling with a changing climate. As distilleries look to source juniper berries from new suppliers, they will face inevitable variation in chemical composition and subsequent variation in flavor, aroma, and mouthfeel. “The various compounds present in the juniper varies depending on where the juniper comes from,” McIntosh explains, “so NMR could help to look at the natural ingredients and what they’re providing for the gin.”
But introducing NMR spectroscopy might not be straightforward. Gleed points out that “very few gin distillers have access to anything more than their noses and a hydrometer,” and NMR equipment is expensive, making it unrealistic for most distillers and possibly lending an advantage to higher-end brands with more funding.
Its use might also mark a shift away from an artistic understanding of gin, in which variety is respected as an unavoidable result of genuine creativity. Indeed, Brown says he “will always prefer organoleptic analysis as, at the end of the day, I’m making gin for people, not computers.”
Meanwhile, Warner’s Distillery employs scientific analysis already—namely gas chromatography and high-performance liquid chromatography—and the company says it is satisfied with its methodology as is. “We know our molecular fingerprints,” it notes.
