A few years ago I began to read more about wine and realized the only way I would ever understand this topic would be to evaluate it in the only way I know how-scientifically, accurately and repeatively. As I began to read about wine I saw words like acidity and sugar and brix and salt. This was good, these were all definitions I could relate to and I liked the way some wine writers would actually correlate their wine descriptions to something that I could actually measure in the lab (and possibly prove them wrong if necessary and insist that they start putting the word “perception”, since sometimes acidity increases salty perception, or sweetness can decrease perception of acid-thus making a wine writers statements of this wine is more acidic than that wine very confusing for someone that actually would go out and measure the two wines and find that what a wine writer wrote was not true.. only to realize later on, they were referring to perception and not reality.

I know I can’t hold a wine writer accountable for what they perceive, but I firmly believe that wine would be a whole lot more approachable if descriptions were based on readings and perceptions were described as exactly that-with the logic of those perceptions written in a book somewhere as well. There are wine writers out there who do just that-describe their wine objectively and accurately using words that are well known in the wine and science world. Karen McNeil , chairman of the CIA Greystone wine department and writer of the award winning The Wine Bible is one of those writers.

Most words like salt and acidity have the same meaning for both the wine novice scientist (me) and the wine writer. But one word in particular can be very confusing-viscosity.

In the world of R&D, viscosity, as it relates to food is a very specific measurable quality that is applied to that food. But because there are different ways to measure viscosity, the terms “high viscosity” or “low viscosity” are not a good way to describe what viscosity really is- the measure of the resistance of a fluid.

Examples will help clarify this confusing point:

Everyday terms: Viscosity means “thickness” thus honey, which is thick, has a high viscosity, but water, which is “thin” has a low viscosity.

When wine writers are describing a wine that is “full bodied”-they are referring to high alcohol, which in turn, they refer to as “viscous” or “high viscosity”. But something with a thick mouth feel might not necessarily always be high in alcohol, so a viscous wine does not always mean “full bodied” or “high alcohol”, which is why no assumptions can ever be made when reading a wine writers words, everything has to be taken in context and related to anything else being said about the wine.

Brookfield Terms: Brookfield Engineering is a Massachusetts based company that sells equipment that measures viscosity. They describe viscosity as “ The internal friction of a fluid, caused by molecular attraction, which makes it resist a tendency to flow”. Viscosity = sheer stress/sheer rate

When using a brookfield unit to measure the viscosity properties of food, one generally can see that thicker products (like honey and corn syrup) will have higher readings than thin products like water or rubbing alcohol.

Which is why, when the wine reader says that high alcohol = full body = high viscosity, the scientist is confused. We automatically start thinking of honey and how the Brookfield readings on honey would be much higher then that of a glass of wine. But honey has no alcohol…

Bostwick Terms: Lastly, to confuse matters even more, is when viscosity is measured by a bostwick. Bostwick measures the distance a material flows in a given time interval. Viscosity, when measured with a bostwick is reported in centimeters. In this case, if something is very thick (like honey) it does not flow very far in a given period of time, as compared to something very thin, like water. Thus in bostwick world, the higher the reading, the LOWER the viscosity of the material!

Thus, when the wine writer says that a wine has a high viscosity, the food scientist who regularly uses a bostwick to measure materials (like I did when I worked in the tomato sauce industry) will automatically think that they mean very thin and runny. But actually, if the wine writer is being constant with the standard wine writers definition, it would really mean the exact opposite.

There is no right or wrong answer when it comes to viscosity, but it is important to always define the terms and equipment using to measure a material. It’s also important when comparing two products side by side, you use the same measuring device (be it the general verbal technique, bostwick or Brookfield) on both samples.

In conclusion, its easy to see how a strict food scientist who has not done any time in the wine world can be very confused when presented with a wine writers description of the word viscosity. Culinologists, get out there and take a wine class because I don’t see the scientists/wine writers and technical experts at Brookfield Engineering getting together any time soon to have a conference on how to make it easier to understand this concept and terminology!

About Rachel Zemser