From the Bench: Bitter Bevels

Aug 31, 2022

A good whiskey old fashioned is one of the great classic cocktails, and it has a surprising horological connection.

You can make an old fashioned with bourbon or rye and sugar or simple syrup, but you have no option about bitters—it’s Angostura or nothing.

The recipe for Angostura bitters has been a closely-guarded secret for nearly two centuries, but the primary ingredient has always been a plant called gentian.

Image licensed under Creative Commons Attribution-Share Alike 4.0 by Chris.urs-o

Gentian is a flowering herb that exists on nearly every continent, and its deeply bitter roots have been used for centuries as a medicinal tonic, particularly around the Alps in central Europe. A German surgeon general devised the Angostura recipe using the herb while serving in Venezuela during the early 1800s, and while it’s always been manufactured in South America or the Caribbean, Angostura’s European origins remain intact.

Because of its wide natural distribution, it’s also used for random non-tonic reasons, and since it grows wild in Switzerland—it’s basically a flowering weed—watchmakers have been using it for ages as a naturally-replenishing source of consumable tools.

Anglage is the French term for the decorative beveling done to watch movements, and is traditionally done by hand, polished to mirror-bright perfection with diamond powder and a thin slip of gentian.

Gentian has historically been used as the tool for his process for a few reasons, not least because it is easily cut to shape and freely available in the garden. The woody stems of the gentian plant are hollow and pithy, which allows them to be cut into a delicate concave wedge, mirroring the shape of the bevel that they will polish. Likewise, the pithy core is full of air pockets that easily hold polishing paste. In some ways, it’s the perfect plant for the job.

Image courtesy of Philippe Narbel, @philippe_narbel_watchmaking

The photo above shows a slip of gentian after it has been shaped into a tool for anglage, and another after the diamond paste is applied. The fine point allows the tool to get firmly into the "interior angles" of a bevel—a kind of bevel that can only be hand formed. The second image has polishing paste in two stages of use. The green paste is fresh and unused, while the black portion is dirty with metal.

Until you’ve tried to properly polish a bevel, the amount of time it takes to achieve the perfect finish cannot be underestimated. Endless hours can be spent just trying to get rid of a single scratch before you realize that the scratch is coming from an embedded abrasive particle on your polishing tool!

This is where a freely replaceable tool becomes invaluable. If you can simply reshape the tool over and over to give yourself an ideal working surface, you take one step closer to achieving perfection.

Nowadays of course, most anglage is done via a cutting process or a rotary tool. Diamond cutters can leave a perfectly flat, mirror-polished bevel in a single pass during the machining process. Small rotary polishers (like a Dremel) or wooden lapping discs can bring the bright lustre of a hand-polished bevel as well, though there is a critical limitation: only proper anglage by hand can give a perfectly-polished inner angle.

Interior angles are simply too sharp for a cutting tool, and even the most delicate of rotary tools. Only a proper finniseur with a precisely-cut slip of gentian can polish those inner corners without softening or diminishing the shape of the bevel.

So the next time you pour yourself an old fashioned, know that you’re sharing in a long tradition of watchmakers, and feel your manual dexterity increase with every sip!

(Photos 4 & 5 courtesy of Philippe Narbel, @philippe_narbel_watchmaking)

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From the Bench: Bitter Bevels