Our Water Kentucky spring water, purified as it flows over limestone rock formations, is perfect for bourbon distilling because it is free of minerals that affect taste. This iron-free limestone water is what makes Kentucky bourbon world-renowned.
		Select Grains The most common bourbon recipes consist of a mixture of at least 51 percent corn, barley malt and rye or wheat. Each distiller takes great care in selecting the grains, making choices based on quality, ripeness and moisture content. These grains are ground into a meal and mixed in intervals with the iron-free limestone water. The mixture is then "mashed" or cooked. During this process the mash produces starch, which upon further cooking become maltose, or grain sugar. A strain of yeast added to the mixture converts the sugar to alcohol, beginning fermentation.
		Fermentation The yeast feeds upon the mixture of water and grain, called sour mash, in huge tubs. The strains of yeast used in fermenting mash in the various bourbon distilleries make one brand of bourbon different from another and are closely guarded secrets in the industry. The yeast is believed to affect the body, aroma and taste of the bourbon as much as the aging process. Many strains have been passed from generation to generation in family-owned distilleries and are still used today. Fermentation takes place in large tubs, some with a capacity of up to 50,000 gallons. In the early days of bourbon making, tubs made of cypress wood were used to hold the mash. Although some distilleries still use cypress, stainless steel tubs are now common. After three to four days of fermenting, the mash is then transferred into another container for distilling. The resulting crystal clear liquid is distilled or separated from the mash. At this point, the mixture is eight to nine percent alcohol, making it 16 to 18 proof.
		Distilling Distilling is the process of removing the alcohol from the mash, accomplished by heating the mash and capturing the vapor, which contains alcohol and flavoring elements. Continuous stills, sometimes 50 feet tall and four feet in diameter, are used to heat the mash and gather the vapor. The vapor cools as it travels through the still and is reconverted into a liquid, known in distilling circles as "low wine" or "distiller's beer," containing from 45 to 65 percent alcohol (or 90 to 130 proof). Most distillers use a doubler still, resembling a large pot, to further refine the low wine into high wine, a clear liquid, ready for aging. High wine contains from 50 to 57.5 percent alcohol (100 to 115 proof), depending on the final product desired. However, the higher the proof of a bourbon, the lower the amount of flavoring elements it contains. Tennessee whiskey distillers add an extra step to the distilling process, filtering the high wine through a multiple-layered maple charcoal filter before aging.
		Charred Oak Barrels The new, white oak barrels are filled to capacity with the high wine, ready for several years of aging. The barrels are charred on the inside, giving bourbon its amber color and mellow but potent taste. Aging must take place for a minimum of two years. If aged less than four years, labeling must include age. Most bourbons are aged from four to eight years. As the liquid ages in the barrel, variations in temperature as the seasons change force it to expand and contract through the caramelized layer of charred wood inside the barrel, "mellowing" it and giving it the distinctive bourbon flavor and appearance. Most warehouses are built on hilltops or in a staggered format in open fields. They contain several stories of "racks" for housing the barrels and usually allow a certain amount of airflow. Because temperature changes often affect barrels stored on the top story more quickly, some distillers rotate the barrels as they age to even out the process. Temperature changes cause pure water in the bourbon to evaporate, so the barrels when opened commonly contain much less liquid than when they were filled. Bourbon loses about three percent of its volume for each year of aging, but contains between 10 and 20 percent more alcohol. Because no two barrels of bourbon have been subjected to the exact changes in temperature, variations in alcohol content and character result. Most distillers blend bourbon from the various barrels to ensure a uniform and distinctive final product.
		The Master Distiller A true artisan, the master distiller is the crucial element in the bourbon making process. Each brand of bourbon has its own recipe, closely guarded by the master distiller. Master distillers are involved from the beginning, carefully selecting grains and keeping a close eye on fermentation. It is said that a good distiller can tell just how long the mash has been fermenting by the shape of the bubbles. The master distiller plays other key roles; selecting barrels, monitoring temperatures and finally, determining when the bourbon is aged to perfection.