Vodka is a clear form of spirit alcohol traditionally made and drunk throughout Eastern Europe.
It has no colour, and is not aged.
Vodka can be made from a mash of beets, grain, or potatoes. In Russia and Poland the best vodka is considered to be made from rye; in Sweden and the Baltic States, wheat is preferred. Potato-based Vodka is liked in Poland, but not in Russia. In North America, corn may be the base grain. Molasses might even be used for cheaper vodkas.
When Vodka is distilled in a pot still, some nuances of what it was made from will come through. Pot stills, though, are not all that efficient at concentrating alcohol, so the alcohol is usually redistilled to increase the proof.
Mass-produced vodkas are usually made in more efficient stills that only require one distillation, particularly in America where any taste nuances in Vodka are forbidden by law. By American law, American Vodka has to be neutral in taste: “(Vodka is…) neutral spirits, so distilled, or so treated after distillation with charcoal or other materials, as to be without distinctive character, aroma, taste or color” (Bureau of Alcohol, Tobacco and Firearms, T.D. 5707, 1949-2 C.B. 252. 1949)
Many North American producers start from Grain Spirits, around 96% alcohol, and then water it down, and do various filtration steps (before or after the water is added) to get the neutrality of taste they want. Because Grain Spirits basically have no taste, the water used becomes the most important flavour element.
In North America, Vodka has become popular because it has no taste. This allows people to drink it with whatever they like (soda pop, juice) without having to learn to like the taste of a particular alcohol. Some wags point out that it also means that North American taste buds never have to grow up.
European brands can be flavoured with herbs, fruits, or spices.
Grading systems differ by country. Poland grades Vodka by purity: standard (zwykly), premium (wyborowy) and deluxe (luksusowy.)
Vodka made from potatoes is oilier than vodka made from grain.
The pH of vodka
Vodka is meant to be a “neutral spirit”, and as such in theory should naturally have a pH in the 6.0 to 7.0 range.1
However, the pH of commercial vodkas ranges wildly.
Many less-expensive American vodkas have a lower pH of around 4.0 because manufacturers are allowed to add citric acid to it up to 1,000 ppm, as a “balancing agent” for the taste.2
The citric acid lowers the pH of these vodkas.
Usually, it is higher quality or premium vodkas that will have a higher pH. Titomirov vodka has a pH of 8.2; Vodka Couture has a pH of 8.88.3.
It’s not just premiums, though. It may also depend on the country and its brewing traditions. Researchers found that “……most Brazilian vodkas had alkaline pH values, with median and mean pH of 8.1 and 7.9, respectively.”4
So, you can’t count on vodka have a low pH (acidic) or high pH (alkaline.) You need to check with the maker of the brand you are curious about.
Vodka was first available in America in the late 1930s, after the repeal of Prohibition. It was made by a company that had purchased the right to use the name “Smirnoff.” Sales of it didn’t take off, and within a few years the company was bought by the Heublein Corporation, along with the rights to the name. Sales were slow until the 1950s, when they began advertising that suggested replacing gin in Martinis with vodka, and how to use vodka in cocktails. By 1976, it had become the best-selling spirit in America.
In January 2010, a British judge ruled that vodka is a defined product. “Mr Justice Arnold ruled today that any brand name derived from vodka but was not vodka was likely to confuse the public. “The evidence clearly establishes that the alcohol-consuming public in the UK, and in particular the vodka-consuming public, have come to regard the term ‘vodka’ as denoting a particular class of alcoholic beverage. …. He found that the marketing of ‘Vodkat’ was calculated to deceive a substantial number of members of the public into believing that the product is vodka”. 
 Herman, Michael. Diageo wins court protection for Vodka London: The Times. 19 January 2010.
Stakhov, Dmitrii (Newlin, Thomas, translator). The Prose and Cons of Vodka. Gastronomica: The Journal of Food and Culture, Vol. 5, No. 1, pp. 25-28. University Of California Press. 2005.
“It should also be noted that vodka… has a very neutral pH, even slightly on the alkali side.” Nicholas Ermochkine and Peter Iglikowski. 40 Degrees East. An Anatomy of Vodka. New York: Nova Science Publishers Inc. 2003. Page 28. ↩
“ATF has therefore concluded that a level of up to 1,000 ppm citric acid is an industry standard that will continue to maintain the current standard of identity for vodka, which has been followed for well over a decade, while meeting ATF’s statutory mandate to protect consumers.” Alcohol and Tobacco Tax and Trade Bureau. US Department of the Treasury. ATF Ruling 97-1. 27 U.S.C. 205; 27 CFR 5.23(a) (3) Accessed August 2016 at .https://www.ttb.gov/rulings/97-1.htm ↩
The Birth of a Legend: “Titomirov Vodka. Le Journal russe de Monaco. August 2015. Accessed August 2016 at .http://www.rusmonaco.fr/index.php/item//650 ↩
Elainy V. S. Pereira et al. Brazilian vodkas have undetectable levels of ethyl carbamate. Química Nova vol.36 no.6 São Paulo 2013. Accessed August 2016 at .http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422013000600014. ↩