the whiskey aerofoil

This whiskey glass is an aerofoil

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Put a ship in a bottle? Painstaking, but easy-peasy. Much tougher to put an airplane in a wine- or whiskey glass. Ok, it’s just a virtual airplane, but it concerns the heart of the magic of flight, the “how does that thing stay up there?” part. That’s right — fasten your seatbelts because there is turbulence inside a properly designed whiskey glass (like for instance the famous Glencairn whiskey glass, see end of article) — it produces lift — and it is caused, like real turbulence for airplanes, by zones of unequal pressure and the resulting interplay of drag and its opposite. The unequal diameters of the widest point of a wine glass bowl compared to the diameter at its mouth, satisfy all the properties of an aerofoil, and this effect provides a scientific foundation for wine- and whiskey glass designs. So much for the cynics who say, “yeah yeah, you just THINK it tastes better!”

It’s beautiful and it works.

But let’s take a step back: like many great inventions, humanity kind of stumbled onto proper glass design for spirits. We have an instinct for aesthetics, and we had beautiful fluted wine glasses with hourglass bodies before we understood how they incorporated aerodynamics, vortex theory, the Bernoulli Principle or other benefits of pressure differentials that deliver aromatic compounds to our senses in enhanced ways. If you research wine- and whiskey-glass shapes you will find that somewhere in the second half of the twentieth century, the catechism emerged that different shapes of wine glass were required or at least desirable, to enjoy different types of wines. Now we’re all repeating it as if it was self-evident all along.

It was no longer the traditional and basic division between reds and whites, but the specific qualities of wine-growing regions and grapes were seen as demanding a different shape of vessel to maximize and enhance the experience. So we have wine glasses designed for Burgundy or Bordeaux, for cabernet, chardonnay, pinot noir, and so on. Actually it has gone a bit further than current science supports, but that’s inevitable. James and Penelope Shackleford’s 2017 book (The Glass of Wine: The Science, Technology, and Art of Glassware for Transporting and Enjoying Wine) is a good comprehensive look in case you are really interested. James Shackleford is Distinguished Professor Emeritus in the Department of Materials Science and Engineering at UC Davis. 

The Riddle of the Riedel

Back in the second half of the 20th century, an Austrian firm named Riedel (long history of enterprising craftsmanship and persistence, back into the 17th C.) created a revolution in wine glass design, by asserting that the shape of the vessel from which we drink changes the perception of what we are drinking. Now we were no longer pairing just wine and meal, we started matching wine and glass. Later on science provided evidence that the physical properties of a wine glass also contain a mathematical ratio that creates turbulence and pressure variations which cause the aromatic molecules of the wine to be delivered in concentrated forms, aided by the shape of the glass and the aerofoil effect. (Get a Riedel set of 8 crystal glasses here.)

NASA’s Demonstration of Airfoil Vortices

The physics of an aerofoil are presented in the cross-section of an airplane wing, where the top is curved and the bottom is flat, so that the path of travel over the wing is longer than the path below the wing, hence the lower air pressure on top, the Bernoulli principle.. . the secret of lift. But Claus J. Riedel gets the credit for pointing out that the glass makes a difference — drawing on the vortex and lift dynamic before he could prove it conclusively. Later science has piled on, and shown that he was right — up to a point. The bowl of a Glencairn whiskey glass is wider than the mouth, and it sets up the aerofoil, counterintuitively, because the narrower top of the glass creates not a blockage, but a faster traveling low-pressure layer, and at the same time air is being drawn down into the bowl, so there is a vortex-like turbulence inside the peaceful domain of the glass. Aircraft wingtips create astonishing vortex patterns based on similar principles and magnified by the fact that the wing is moving.  (Actual photo using colored smoke to reveal aerofoil-generated vortices: NASA Langley Research Center) NASA Langley Research Ctr.

“Based on his unique designs, Claus Riedel was the first in history to recognize the effect of shapes on the perception of alcoholic beverages. His work has influenced and changed the appearance of stemware forever. His masterpiece ‘Sommeliers’ was introduced in Orvieto, in 1973, the first-ever stemware line to be based on the character of wine.” The Riedel company website




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