We go inside the mind of George F. Manska for an analytical look at Sensory Science for Bartenders. In this segment, George gives us a lesson on how swirling affects aroma.

 

 

As a bartender, you will from time to time here a question from your customers regarding swirling your drink. Cocktails aside, for obvious reasons, swirling neat spirits is an essential part of nosing and evaluating spirits. Wine lovers understand the need for swirling, and beer lovers swirl when the liquid is low enough in the glass to swirl without spilling. No swirling = no evaporation (except ethanol) = no character smells. Swirling releases aromas for detection. Every liquid has an invisible force at its interface with the atmosphere (air) called surface tension. Why can a water bug walk on water? Surface tension. If surface tension keeps a water bug on top of a liquid, it can also keep aroma molecules. Swirling breaks surface tension allowing more aroma molecules to escape (ask a knowledgeable wine guy, that’s why the swirl).

• Swirling produces more evaporated aromas.
• Once swirled, “legs” or “tears” appear, caused by the surface tension gradient between water and ethanol improves evaporation (Gibbs-Marangoni effect).
• Gravity creates vertical shear on vessel sidewalls, disrupting surface tension and improving evaporation as liquid returns to the liquid pool in the glass. More aromas come from the vertical shear and “legs” than from the surface of a resting vessel of liquid.

Different glassware designs have different swirling factors: Note that the snifter appears to be the best swirling glass of the three most common shapes and styles. While that is true, the convergent rim shape forces one to place the nose inside the glass where the highest concentration of ethanol interferes with picking up the more subtle nuances of the spirt. This is the one case where the best swirling glass is also the highest ethanol concentrator. Ethanol must have somewhere to go to get away from the nose. That’s why wide mouth glasses are better for high ABV spirits.

 

 

Common Swirling Myths busted:

• Myth #1: Legs or tears are an indication of body and sweetness. False: Legs are formed by the difference in surface tension and molecular attraction (strong for water, weak for ethanol). Legs only indicate the presence of both alcohol and water. Legs vary by the microscopic surface porosity of the glass, the presence of soap or surfactants. They are precursors of nothing sensory. On the other hand, the thick legs from highly sweetened and fortified wines and liqueurs, may have a slightly higher viscosity which can add to the always present Marangoni effect. Not always possible in the bar business due to local sanitation laws, but the choice at home is to wash in hot water and hand polish your glassware to avoid soap residue.
• Myth #2: Don’t swirl beer: The standard bartender beer pour is close to the top rim to keep the critical customer happy, making it difficult to swirl, and beer’s effervescence, caused by CO2 or N2, provides some aroma as the bubbles pop. A thick, foamy head can hinder odor detection, and slight swirling, or slowly rotating a tilted glass to wet the inside wall will aid in aroma detection. When partially consumed, the increased headspace provides swirling or rotating room. Get your nose down into the headspace with low ABV beers and wines. Many beer drinkers hold the opinion that wine drinkers are snobs, and reject any portrayals resembling wine drinking, including stems and swirling. Experienced beer drinkers swirl slowly or tilt and rotate their glass at lower beer levels and decreased effervescence to pick up more aromas, and they sniff continuously.
• Myth #3: Don’t swirl spirits: For decades, accepted glassware for scotch has been the hard-to-swirl tulip. During the scotch resurgence in the ‘60s and ‘70s, brand ambassadors and educators quickly became aware of Americans’ lack of tolerance to strong ethanol, because they were used to adding soda, fruit juice and ice to spirits to cover the smell of poorly made illegal prohibition booze. They recommended adding water, wafting aromas toward the nose to pre-condition, and warning drinkers not to swirl, all of which slightly diminish nose burn. Scotch sales skyrocketed, but aroma perception suffers with all these methods as they dumb down all aromas for the sake of reducing pungent ethanol.
• Myth #4 Swirl clockwise in the northern hemisphere, counterclockwise in the southern: Swirling delivers aromas regardless of direction. It’s all about swirling velocities fast enough to break surface tension. Vigorous swirling is better. Right-handed drinkers tend to swirl counterclockwise, and left-handed drinkers tend to swirl clockwise.

Placing a lid or a hand over the mouth of the glass while swirling concentrates evaporated aromas. Serious spirits tasters may use glass caps (must be thoroughly cleaned) or disposable sanitary paper caps as commonly used in hotel rooms. Lids are great for side-by-side comparisons to reduce cross-spirit aroma contamination.

Summary: The purpose of swirling is to release aromas for detection and evaluation. Crutches to alleviate ethanol nose-burn from spirits, such as adding water, wafting, breathing in with mouth open hinder aroma detection. Use glassware with an open, large rim or a whiskey tumbler, swirl vigorously, uncover, sniff, and enjoy. Forget tulips, which concentrate and shove pungent ethanol up the nose distracting and obliterating the more subtle flavors. Next: Adding Water to Whiskey.

 

 

About George Manska

George is an entrepreneur, inventor, engine designer, founder, Chief R&D officer, Corporate Strategy Officer, CEO Arsilica, Inc. dedicated to sensory research in alcohol beverages. (2002-present). He is the inventor of the patented NEAT glass, several other patented alcohol beverage glasses for beer and wine, (yet to be released). Director ongoing research into aromatic compound behavior, and pinpointing onset of nose-blindness. George is a professional consultant for several major spirits competitions, has been published in the MDPI Beverage Journal Paper, is the founder or member of over seven different wine clubs for the past fifty years, is a collector of wines and spirits, has traveled the world, and is an educator and advisor of multiple spirits sensory seminars.

The post Inside Manska’s Mind: Advice for Bartenders on the Sensory Science of Swirling appeared first on Chilled Magazine.

Source: Mixology News