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The Role of Earth Sciences in Historical American Whiskey
Production
Joe T. Elkins, Ph.D.
Co-founder/Distiller, Elkins Distilling Co.
Associate Professor, Earth and Atmospheric Sciences
University of Northern Colorado
Popular types of American Whisky*
*Whisky: all grain mash, distilled to no higher 80% ABV, bottled to no lower than 40% abv)
– Rye (min. 51% rye bill, particularly popular pre-prohibition, early America)
– Wheat (min. 51% wheat)– Barley (aka malt whisky, 51% malted barley)
• Corn– Bourbon (51-80% corn)– Tennessee ( 80% corn, may use Lincoln County
Method)– Corn (80% or more corn)
Corn-based whisky
• Corn used as a source of starch, converted to fermentable sugar during mashing
• Amylase enzymes are introduced via a malted grain sources (commonly, malted barley, or malted rye)
• Low dissolved Fe (iron) content water to aid starch conversion
• Sour mashing used to set the pH for mashing and as a source of bacteria for acid->ester production
Observations
• Historically, brewing was constrained to cooler temperatures than distilling
• Historically, distilleries making whisky from corn and using sour mashing confined to narrow range of geomorphic provinces in Kentucky and Tennessee
Technological innovations that changed the map
• Commercial refrigeration (1870’s)
• Water treatment
– Sand Filtration (1804)
– Chlorine ( John Snow, 1854)
– Ion Replacement (1903)
Effect of Climate
• Warm temperatures favor bacterial growth over yeast during fermentation
– Detrimental to brewing
– Beneficial to sour mash whisky making
Effects of geology and hydrogeology
• Low Fe (iron) water is key to making whiskey from corn
• Corn used as a source of starch, converted to fermentable sugar during mashing
• Amylase enzymes are denatured in water over 25ppm Fe (Smiley, 1999 and Miller, 2016)
KY Whisky Distilleries
• The Knobs
– First Order Streams
– Headwaters of Salt River Watershed
– Groundwater-fed surface flow
– Ordovician Limestone aquifers: low Fe, high Ca
• Inner Bluegrass Region
– Groundwater-fed surface flow
– Kentucky River and Salt River Water sheds
– Ordovician Limestone aquifers: low Fe, high Ca
Farrar Distillery (1875-1902)
Cascade Hollow Distillery (1877-1910, 1958 present)
Jack Daniel’s Distillery (1866-1910, 1938-present)
Overview of Environmental Constraints for Tennessee Whiskey Distilleries Prior to
Industrialization
-Located in the hollows of the Dissected Escarpment of the eastern Highland Rim geomorphic province
-Situated on First Order Streams
-Distilleries had first use of water in watershed
-Water sources are groundwater-fed near the contact between Mississippian and Ordovician formation
-Water sources are low in Fe, and high in Ca derived from Mississippian and Ordovician aquifers
Similarities of KY and TN Whiskey Distilleries
• The Knobs and Dissected Escarpment of the Eastern Highland Rim most similar
– Topographic context
– First Order Streams
– Groundwater-fed surface flow
– Headwaters
– PZ Limestone aquifers: low Fe, high Ca
Future work
• Understanding the nature of Ca in mashing and mellowing/aging
– Implication for accelerated mellowing
• How the Inner Bluegrass differs from the The Knobs in terms of groundwater chemistry
• Why Fe denatures amylase enzymes