The Anatomy of a DUI – An Overview of Alcohol

Over the past few months I have been asked by many individuals various questions relating to DUI.  I believe that knowledge is power, and when you have the knowledge you are in a better position to protect yourself.  Therefore, I decided to write this column to provide information relating to DUI so to educate and inform and to help individuals have a better understanding of DUI.

chpBefore I discuss the anatomy of an actual DUI arrest, I believe it important for the reader to have a basic understanding of the physiology of alcohol itself.   By understanding how alcohol works within our body, and how it relates to ones blood alcohol concentration (BAC), one can better understand how the consumption of alcohol can lead to a DUI arrest, or even avoid a DUI arrest by controlling behaviors related to the consumption of alcohol.

Overview of Alcohol: Arguably, alcohol is the most abused drug in the United States.  "Alcohol" is the name given to a family of closely related and naturally-occurring chemicals.  Alcohols are molecularly very similar and produce similar effects. They produce intoxicating effects when ingested into the human body. Only one of them, Ethanol, is meant for human consumption. However, when ingested in substantial quantities it too can cause death.

Two of ethanol's best known analogs are methyl alcohol (or methanol), commonly called "wood alcohol", and isopropyl alcohol (or isopropanol), also known as "rubbing alcohol".

As for human consumption, Ethanol is what interests us, because it is the kind of alcohol that features prominently in impaired driving. Ethanol is beverage alcohol, the active ingredient in beer, wine, whiskey, liquors, etc. Ethanol production starts with fermentation. That is a kind of decomposition in which the sugars in fruit, grains and other organic materials combine with yeast to produce the chemical we call ethanol. This can occur naturally, as yeast spores in the air come into contact with decomposing fruit and grains. However, most of the ethanol in the world didn't ferment naturally, but was produced under human supervision. When an alcoholic beverage is produced by fermentation, the maximum ethanol content that can be reached is about 14-15%. At that concentration, the yeast dies, so the fermentation stops.

Obtaining higher ethanol content requires a process called distillation. This involves heating the beverage until the ethanol "boils off", then collecting the ethanol vapor. It is possible to do this because ethanol boils at a lower temperature than does water. Distilled spirits is the name we give to high-ethanol-concentration beverages produced by distillation. These include rum, whiskey, gin, vodka, etc. The ethanol concentration of distilled spirits usually is expressed in terms of proof, which is a number corresponding to twice the ethanol percentage. For example, an 80-proof beverage has an ethanol concentration of 40 percent.

Over the millennia people have used and abused ethanol, and some standard-size servings of the different beverages have evolved. Beer, for example, is normally dispensed in 12-ounce servings. Since basic beer has an ethanol concentration of about 4%, the typical bottle of beer contains a little less than one-half ounce of pure ethanol (now keep in mind that craft beers can have alcohol concentrations as high as 8-9%, and some higher).  A standard glass of wine has about four ounces of liquid. On average, wine is about 12 percent alcohol, so the glass of wine also has a bit less than one-half ounce of ethanol in it (some wines have a much higher alcohol concentration). Whiskey and vodka and other distilled spirits are dispensed by the "shot glass", usually containing about 1 ¼ ounce of fluid.  At a typical concentration of forty percent ethanol (80-proof), the standard shot of whiskey has approximately ½ ounce of ethanol. Therefore, as far as their alcoholic contents are concerned, a can of regular beer, a 4 oz. glass of wine, and a shot of whiskey are all about the same.

In the next part of this article, I will discuss the physiology of alcohol and how it works within the human body.  Stay tuned… and until then, be safe.