For those who are new to whiskey drinking, new to literacy, or those simply reviewing before you impress Rob Samuels at a whiskey tasting, our friends at Michter’s Whiskey have put together a captivating “dictionary” of whiskey terms so that we’re never caught wondering what the difference is in the mashbills of bourbon, rye or even, God forbid, a Canadian.
Age: This term refers to the period during which, after distillation and before bottling, distilled spirits have been stored in oak barrels.
Air-Flow: Air-flow is directly related to and a critical component of the maturation process of barreled whiskey, bourbon and rye. Much attention is paid to it in the design of a good warehouse intended for aging. Proper air-flow is used to maintain temperature and humidity in ways that optimize maturation. Air-flow is controlled by opening and closing strategically placed windows in barrel warehouses, and in many cases it is supplemented by specially designed circulation fans. When an increase or a decrease in the temperature of the liquid in the barrels results in a change of approximately 13º Fahrenheit or more, a whiskey “cycle” is achieved as the whiskey moves into and out of the wood. In the case of Michter’s, it cycles into both the char line and the caramel layer that results from toasting.
American Whiskey: American whiskey is whiskey made in the United States, distilled to no greater than 160 proof from a fermented mash of corn, rye, wheat, malt barley and/or malted rye grain. It differs from Scottish or Irish whisky because the grain is not dried with smoke, so American whiskeys usually have a fuller, less peaty/smoky taste. American whiskey is usually separated into many categories, with the prevalent ones being bourbon, rye, and blended. In the more narrow legal sense of the term, American whiskey must be made in the U.S.A. and unlike bourbon, and rye, it can be aged in barrels that have previously been used to age other whiskey. Also, unlike bourbon with its 51% or more corn mashbill and rye with its 51% or more rye grain mashbill, American whiskey can be made from a mashbill where no one grain needs to be the majority.
Angel’s Share: Whiskey is aged in wood barrels in order to mellow the high proof un-aged distillate as well as to flavor it with the rich characteristics of the oak barrels in which it is stored. The “angel’s share” is the portion of whiskey that is lost to evaporation during the aging process. Michter’s has a much larger angel’s share than most whiskeys because we heat cycle the warehouses, thereby causing significantly more whiskey to evaporate during aging. Unlike most ordinary whiskey distillers, we go to the extra expense because we believe heat cycling results in a much richer, smoother product.
Barrel Preparation & Toasting: Coopers, aka barrel makers, season the oak components by drying them outdoors where they are exposed to the elements. This process can take anywhere from three months to two years. The seasoning reduces the harsher tannins and those notes are effectively leached out. The longer the wood is allowed to season, the softer the notes that will be imparted to the whiskey. After air drying, the cooper will kiln dry the barrel staves and barrel heads to achieve consistent moisture. After kiln drying, the cooper will run the wood through an equalizing and conditioning process to prepare it for machining.
The staves are assembled and heated until pliable so that they can be bent into the shape needed to make a barrel. Unlike the untoasted barrels used by many distillers who only char and do not toast, Michter’s barrels are toasted with heat before charring. Light, medium, or heavy are the general variations of barrel toast. Medium toast, for example will impart more flavor and less color than heavy toast. Proper toasting also enhances whiskey with vanilla, smoke and spicy notes reminiscent of cloves.
Blended Whiskey: A blended whiskey is a whiskey that has been mixed with “neutral spirits,” i.e. unaged alcohol. The blend must contain at least 20% whiskey or at least a 20% blend of whiskeys. In contrast, the entire families of Michter’s whiskeys, including Michter’s Unblended American Whiskey, are 100% whiskey and never stretched with neutral grain spirits.
Bonded Whiskey: This whiskey is also referred to as “Bottled-in-Bond,” and it is subject to the rules established by the U.S. Bottled-in-Bond Act of 1897. Bonded whiskey must be produced by one distiller during one distillation “season” by the same distilled spirits plant. There are two bonded whiskey seasons: “Spring” (May to June) and “Fall” (July to December). It must be aged a minimum of four years in a federally bonded warehouse.
Bourbon: By law bourbon whiskey must be made in the United States and must be fermented from a mashbill of at least 51% but not more than 80% corn. Unlike vodkas it must first come off the still at no higher than 160 proof, and entered in wood at not more than 125 proof. It must be stored for at least two years in new, charred new oak barrels.
Charred Oak Barrels: The definition is simple. These are barrels made of oak that are burnt on the inside, but the real question is how are they burnt and why? In order to char new oak barrels, the barrels are set over an open flame, oxygen is added to the flame and the flame shoots up through the inside of the barrel, charring it. The barrels are charred because it imparts more flavors and color to the whiskey. The different flavors that the whiskey absorbs depend on the how long and at what temperature the barrel is charred. Selection of the right char and the right barrel can make a big difference in the taste of the final product after its maturation. Charring is a different process than toasting, an additional process that Michter’s uses. Please see our definition for “Barrel Preparation & Toasting.”
Cooker: This heated tank receives the fermented mash from the fermenter and transforms it into the 8-9% distiller’s beer that is fed into the still.
Cooperage: Whiskey distillers use the term “cooperage” to refer to barrels. The people who make barrels are called “coopers.”
Distillation: Distillation is the process of increasing alcohol level and removing impurities by using a pot still or a continuous (column) still. In a pot still, fermented mash is heated batch by batch to produce steam in which the more volatile alcohol, with its lower boiling point than water, is suspended and then cooled until it condenses back into a more concentrated liquid. In a pot still this process is almost always repeated, to achieve the 80 proof or more alcohol level of most whiskeys. In a column still, the distiller’s beer is continually fed into the still.
Distiller’s Beer: Roughly 8-9% alcohol, distiller’s beer is the result of cooking the fermented mash in a cooker, and it is what is fed into a still to begin the distillation process.
Entry Proof: Entry proof is the proof at which the distillate that comes off the still is first put into a barrel for storage and maturation. Typically, whiskey distillers fill their barrels with distillate at an entry proof around 125 proof. Michter’s Rye and Bourbon barrels are filled at 103 proof. The proof of the spirits off most whiskey stills is typically between 120 and 160 proof. Water is added to the distillate to reduce the spirits to the desired entry proof.
Federal Excise Tax: U.S. distillers are required to pay a federal excise tax on their spirits products when the spirit leaves the bonded premises of the “DSP” (distilled spirits plant). The Federal excise tax rate is currently $13.50 per proof gallon. This tax is computed based on the amount of alcohol in a product: i.e., a 90 proof bottle is subject to a higher excise tax than an 80 proof bottle. The current 2011 federal excise tax charges on a 750 ml bottle of 80 proof whiskey is $2.14.
Fermentation: This is the process by which alcohol is produced from a grain, fruit, plant, or sugar source. Fermentation takes place when the enzymes in yeast convert starch into ethyl alcohol (carbon dioxide is a byproduct of fermentation). Fermentation at a distillery generally occurs in a tank called a fermenter. The nature of the yeast strain used for fermentation can affect the ultimate flavor and character of the whiskey.
Fermenter: At a distillery, this is the name of the tank in which fermentation occurs. The fermenter usually made of stainless steel although some of the older fermenters were made of cypress wood.
Gauge: The determination of the proof and quantity of spirits.
Heads & Tails & Hearts: Heads and tails are terms used to refer to the first distillate at the beginning (the “heads”) off a still and the last distillate off the still (the “tails”) during a particular distillation. Generally, good distillers discard the “heads” and the “tails” because the distillate off the still in the middle, referred to as the “hearts”, between the “heads” and “tails” is of higher quality.
Heat Cycling: When whiskey is stored in barrels, the changes in the weather naturally causes the liquid to expand and contract. This allows the whiskey to move into and out of the barrel and absorb the flavor and character of the wood. In the case of whiskey in a Michter’s barrel with it’s toast, the whiskey picks up flavor not only from a char line, which most other distillers have, but also from a rich caramelized layer resulting from careful toasting. Whiskey “cycles” (i.e. expands and contracts) into the barrel when a temperature change of roughly 13º F or more occurs. A cycle usually occurs 6 times in a typical Kentucky year as the seasons change. Heat cycling is an extremely costly practice used by very few whiskey companies to raise and lower temperatures in barrel warehouses to create an extra cycling of the whiskey into the barrel. Depending on the type of whiskey, Michter’s barrels undergo this heat cycling process an additional 6 to 8 or more times per year. Therefore Michter’s rye, bourbon, or American whiskey will have extra richness because it has cycled 12 to 14 or more times per year into the wood in contrast to typical whiskeys which have cycled only around 6 times per year. The reason other distilleries are reluctant to adapt Michter’s style heat cycling is that it vastly increases the cost of goods by greatly increasing the “angel’s share” evaporation of the whiskey in the barrel.
Mashbill: A “mashbill” is the distillers’ nickname for the grain ingredients in the whiskey recipe. The mashbill contains the particular grain types and precise percentages used in a particular whiskey’s mash that is to be fermented. Most distillers do not release their mashbill because it is proprietary information and a secret critical to creating the distinct flavor of their whiskey. Bourbon must have a mashbill of at least 51% corn, and rye must have a mashbill of at least 51% rye grain. Corn, rye, malt, and even wheat are frequent grains used in mashbills by America’s whiskey distillers.
Nine Liter Case: A nine liter case consists of 9 fluid liters and is the standard case size used by whiskey companies and their distributors to measure sales in the U.S. This is normally translated into 12, 750 ml sized bottles.
Original Proof Gallons (OPG): The number of proof gallons first entered into the barrel at initial barreling before evaporation as “angel’s share” occurs over time.
Proof: This is a measurement of how much alcohol is contained in a spirit. In the U.S. alcohol proof is twice the percentage of the alcohol by volume. Thus, if a whiskey is 45% alcohol by volume, it is 90 proof. Most American rye, bourbon, and whiskey are 80 proof (40% alcohol by volume) or more.
Proof Gallon: The industry standard of measurement used by whiskey distillers and bottlers is the proof gallon. One liquid gallon (often referred to as “wine gallon”) of spirit at 100 proof constitutes one proof gallon. As proof gallon is calculated based on the amount of liquid and the alcohol strength, one gallon of 80 proof constitutes .8 proof gallons, two gallons of 80 proof bourbon constitutes 1.6 proof gallons, and so on.
Regauged Proof Gallons (RPG): The number of proof gallons actually currently present in a barrel or a holding tank. The OPGs (Original Proof Gallon) placed in a barrel will be more than the RPGs present in the barrel after the evaporation of “angel’s share” takes place in the years of aging.
Ricks: Typically made of wood and generally three barrels high, ricks are the lattice-like sturdy structures on which barrels are stored. The particular warehouse floor (higher floor vs. lower floor) on which the barrels are located can subtly influence the maturation. Barrels are stored bung/stopper up.
Rye: American rye whiskey must be made in the U.S., must contain at least 51% rye, and must come off the still at less than 160 proof. Additionally, it must be stored for at least two years in new, charred white oak American barrels. Much of the rye whiskey produced is used in small amounts to blend with other whiskeys, but straight rye, like Michter’s, is nothing but pure rye whiskey. Because of the flavor of the grain, good rye whiskey has a distinct taste that many consider spicier and livelier than bourbon.
Single Barrel: Single Barrel is used to describe a super premium class of whiskey where each bottle literally comes from one barrel. Most bourbons, ryes, and American whiskeys are not labeled Single Barrel, and a bottle of typical non-Single Barrel rye or bourbon contains a mixture of whiskey from several different barrels. When a bottle of whiskey is marked “Single Barrel,” the whiskey comes from only one barrel. Like children from the same parents, after years of aging, two barrels of whiskey from the exact same distillation and placed in barrels at the exact same time will come out tasting a bit different because the two individual barrels are a bit different. Many whiskey enthusiasts like to compare and savor the flavors in bottles of their favorite whiskeys taken from different barrels.
Small Batch: This term is generally used to describe spirits crafted with the precise production, overall care and filtration and bottling that are only possible in smaller than normal commercial quantities. Michter’s small batch whiskeys are released in batches a fraction of the size of many other whiskeys labeled small batch.
Sour Mash: Sour Mash whiskey is produced by the process of taking small amounts of previously fermented mash and using this as the starter for a new mash to be fermented. Some people liken this to the process of making sourdough bread.
Yeast: Yeast is an active culture that is placed into the fermentation tank to start fermentation. Yeast is added to convert the sugar and starch in the mashbill grains into alcohol. Carbon dioxide is a by-product of the process of fermentation
Yeast String: Most distillers of bourbons and rye whiskeys have their own particular string of yeast that has been cultivated and grown over many years. A different yeast string can impart a different character to a whiskey. The yeast strings used to ferment Michter’s are so important to us that they are stored in a dormant form in an out of state facility just in case something happens to our precious yeast strings at the distillery.
Wort: The wort is the soupy mix of grain and water to which yeast is added to start the fermentation process.
Source: Michter’s Whiskey (http://www.michters.com/whiskey-terms)