When people think of charcoal filtration and whisky, they usually default to Tennessee. Turn the clock back to the 19th century, and most of the whisky manufactured in North America was charcoal filtered or leached. By 1887, 74 per cent of American whisky was rectified before barrelling, the balance being straight bourbon and rye. Indian corn was 90 per cent of the nation’s mash bill and, along with rye, rendered significant volumes of grain oil, leading to problems for whisky palatability unless treated by charcoal rectification.
East coast farmers crossing the Appalachian mountains introduced charcoal rectification practices to the Ohio Valley by the 19th century. In the Nashville area, 61 registered distilleries operated in 1799; 10 years later, 756 were registered in Tennessee. With corn-only mashes or small contributions by small grains, distillers began employing charcoal rectification to make their whisky more drinkable. As domestic colonial records are meagre during the early decades of European settlement, the first mention of charcoal leaching was by William Pearson. He brought his family recipe using a barrel of powdered charcoal from Pennsylvania to Bedford County, middle Tennessee, by 1812.
Before the Civil War, middle Tennessee was America’s grain basket, the nation’s most productive state for corn cultivation. The region earned an enviable reputation for its corn whisky, where mashes were almost exclusively corn, with some small grains for enzymic saccharification. The indigenous Cherokee people raised varieties of southern white dent before European settlement, and Tennessee distillers mashed this popular corn varietal until the mid-20th century. Abundant in starch and a germ rich in oil, large quantities of oil hydrolysed from the mash during fermentation. Distillation converted much of these oils into higher alcohols or fusel oils on traditional pots and patent wooden steam stills.
Many Tennessee distilleries employed a closed system using multi-chambered wooden steam stills, which aggravated the fusel problem. Charcoal was the most efficacious and cost-effective method to remove these undesirable oils and some esters from the distillate. Charred white oak barrels also filtered fusel oils during maturation as the charcoal membrane absorbed these compounds. Oxidising and chemical interactions transformed others into flavoursome compounds that made straight whisky delectable. Every distiller had a secret recipe, as there were endless combinations of burnt local hardwoods, the size of the charcoal pieces, the depth and type of container, or whether the distillate trickled, ran or was left to soak. They described their rectifying process as leeching (sic), mellowing or the extra blessing. Today, of the three dozen Tennessee whisky distilleries, most can claim a proprietary formula. After Prohibition, Jack Daniel’s Distillery was the only distillery in North America using charcoal rectification from 1938, joined by George Dickel in 1958. Jack Daniel’s method is drop-by-drop through four metres of packed pea-sized charcoal in wooden mellowing vats over four days. George Dickel floods its metal tanks filled with pulverised charcoal, soaking 4oC chilled distillate and slow-filtering for over a week.
From the 1850s, the distilleries around Lincoln County labelled their product Lincoln County corn whiskey, marketing the provenance of their famed corn, especially the Tennessee Red Cob white dent variety, cultivated in Lincoln and adjacent counties of Bedford, Moore, Coffee and Franklin. In the 1890s, Jack Daniel borrowed this corn whisky term to describe the charcoal rectification method at his distillery in Moore County. In 2013, the Tennessee legislature enshrined in state law ‘filtered through maple charcoal’ to define Tennessee whiskey, also marketed as the Lincoln County Process. At the federal jurisdiction, Tennessee whiskey has been recognised as a distinctive product since March 1941, defined as “bourbon whiskey charcoal rectified to change its organoleptic character”.
All thanks to rectification through charcoal sugar maple, Tennessee whiskey gets an extra blessing.
East coast farmers crossing the Appalachian mountains introduced charcoal rectification practices to the Ohio Valley by the 19th century. In the Nashville area, 61 registered distilleries operated in 1799; 10 years later, 756 were registered in Tennessee. With corn-only mashes or small contributions by small grains, distillers began employing charcoal rectification to make their whisky more drinkable. As domestic colonial records are meagre during the early decades of European settlement, the first mention of charcoal leaching was by William Pearson. He brought his family recipe using a barrel of powdered charcoal from Pennsylvania to Bedford County, middle Tennessee, by 1812.
Before the Civil War, middle Tennessee was America’s grain basket, the nation’s most productive state for corn cultivation. The region earned an enviable reputation for its corn whisky, where mashes were almost exclusively corn, with some small grains for enzymic saccharification. The indigenous Cherokee people raised varieties of southern white dent before European settlement, and Tennessee distillers mashed this popular corn varietal until the mid-20th century. Abundant in starch and a germ rich in oil, large quantities of oil hydrolysed from the mash during fermentation. Distillation converted much of these oils into higher alcohols or fusel oils on traditional pots and patent wooden steam stills.
Many Tennessee distilleries employed a closed system using multi-chambered wooden steam stills, which aggravated the fusel problem. Charcoal was the most efficacious and cost-effective method to remove these undesirable oils and some esters from the distillate. Charred white oak barrels also filtered fusel oils during maturation as the charcoal membrane absorbed these compounds. Oxidising and chemical interactions transformed others into flavoursome compounds that made straight whisky delectable. Every distiller had a secret recipe, as there were endless combinations of burnt local hardwoods, the size of the charcoal pieces, the depth and type of container, or whether the distillate trickled, ran or was left to soak. They described their rectifying process as leeching (sic), mellowing or the extra blessing. Today, of the three dozen Tennessee whisky distilleries, most can claim a proprietary formula. After Prohibition, Jack Daniel’s Distillery was the only distillery in North America using charcoal rectification from 1938, joined by George Dickel in 1958. Jack Daniel’s method is drop-by-drop through four metres of packed pea-sized charcoal in wooden mellowing vats over four days. George Dickel floods its metal tanks filled with pulverised charcoal, soaking 4oC chilled distillate and slow-filtering for over a week.
From the 1850s, the distilleries around Lincoln County labelled their product Lincoln County corn whiskey, marketing the provenance of their famed corn, especially the Tennessee Red Cob white dent variety, cultivated in Lincoln and adjacent counties of Bedford, Moore, Coffee and Franklin. In the 1890s, Jack Daniel borrowed this corn whisky term to describe the charcoal rectification method at his distillery in Moore County. In 2013, the Tennessee legislature enshrined in state law ‘filtered through maple charcoal’ to define Tennessee whiskey, also marketed as the Lincoln County Process. At the federal jurisdiction, Tennessee whiskey has been recognised as a distinctive product since March 1941, defined as “bourbon whiskey charcoal rectified to change its organoleptic character”.
All thanks to rectification through charcoal sugar maple, Tennessee whiskey gets an extra blessing.
