Brandy is a spirit produced by distilling wine. Brandy generally contains 35–60% alcohol by volume (70–120 US proof) and is typically taken as an after-dinner drink. Some brandies are aged in wooden casks, some are coloured with caramel colouring to imitate the effect of aging, and some brandies are produced using a combination of both aging and colouring. In broader sense, the term "brandy" also denotes liquors obtained from distillation of pomace (pomace brandy) or mash or wine of any other fruit (fruit brandy). These products are also named eaux-de-vie. Varieties of wine brandy can be found across the winemaking world. Among the most renowned are Cognac and Armagnac from southwestern France. The origins of brandy were clearly tied to the development of distillation. While the process was known in classical times, it wasn't used for significant beverage production until the 15th century. Initially wine was distilled as a preservation method and as a way to make it easier for merchants to transport. It is also thought that wine was originally distilled to lessen the tax which was assessed by volume. The intent was to add the water removed by distillation back to the brandy shortly before consumption. It was discovered that after having been stored in wooden casks, the resulting product had improved over the original distilled spirit. In addition to removing water, the distillation process led to the formation and decomposition of numerous aromatic compounds, fundamentally altering the composition of the distillate from its source. Non-volatile substances such as pigments, sugars, and salts remained behind in the still. As a result, the taste of the distillate was often quite unlike that of the original source. As described in the 1728 edition of Cyclopaedia, the following method was used to distill brandy: A cucurbit was filled half full of the liquor from which brandy was to be drawn and then raised with a little fire until about one sixth part was distilled, or until that which falls into the receiver was entirely flammable. This liquor, distilled only once, was called spirit of wine or brandy. Purified by another distillation (or several more), this was then called spirit of wine rectified. The second distillation was made in balneo mariae and in a glass cucurbit, and the liquor was distilled to about one half the quantity. This was further rectified—as long as the operator thought necessary—to produce brandy. To shorten these several distillations, which were long and troublesome, a chemical instrument was invented that reduced them to a single distillation. To test the purity of the rectified spirit of wine, a portion was ignited. If the entire contents were consumed by a fire without leaving any impurities behind, then the liquor was good. Another, better test involved putting a little gunpowder in the bottom of the spirit. If the gunpowder could ignite after the spirit was consumed by fire, then the liquor was good. As most brandies have been distilled from grapes, the regions of the world producing excellent brandies have roughly paralleled those areas producing grapes for viniculture. At the end of the 19th century, the western European markets, including by extension their overseas empires, were dominated by French and Spanish brandies and eastern Europe was dominated by brandies from the Black Sea region, including Bulgaria, the Crimea, and Georgia. In 1884, David Sarajishvili founded his brandy factory in Tbilisi, Georgia, a crossroads for Turkish, Central Asian, and Persian trade routes and a part of the Russian Empire at the time. Armenian and Georgian brandies, called cognacs in the era, were considered some of the best in the world and often beat their French competitors at the International Expositions in Paris and Brussels in the early 1900s.[citation needed] The storehouses of the Romanov Court in St. Petersburg were regarded as the largest collections of cognacs and wines in the world with much of it from the Transcaucasus region of Georgia. During the October Revolution of 1917, upon the storming of the Winter Palace, the Bolshevik Revolution actually paused for a week or so as the participants gorged on the substantial stores of cognac and wines. The Russian market was always a huge brandy-consuming region in which home-grown varieties were common but much of it was imported. The patterns of bottles followed that of the western European norm. Throughout the Soviet era, the production of brandy was a source of pride for the communist regime as they continued to produce some excellent varieties, especially the most famous Jubilee Brandies of 1967, 1977, and 1987.[citation needed] Remaining bottles of these productions are highly sought after, not simply for their quality, but for their historical significance.