what's a bourbon?

A Straight Bourbon (as opposed to Tennessee whiskey) can be made anywhere as it is the method of production, not the geographical area that defines it. Bourbon must contain at least 51% corn, be distilled to a strength of not more than 80%abv, stored in charred white oak barrels at a strength no higher than 62.5%abv for at least two years and reduced at bottling to no lower than 40%abv.

who invented bourbon?

According to legend it was the Reverand Elijah Craig who first discovered the burnt barrel method of ageing the whiskey we now call Bourbon. A distiller of note, he was supposedly warming oak staves over a fire to make a barrel when he was interrupted. On his return he found the wood heavily charred. He made the barrel anyway and filled it with whiskey. Another more believable story is that he had a barrel that had been used to store fish. Rather than discard the barrel, he burnt it to remove the smell. Anyway, he found that the charred barrel contained a greatly improved whiskey, a darker mellow spirit with a vanilla sweetness. When his distinctive dark coloured whiskey was sent down the river to New Orleans numerous requests came back for the whiskey from Bourbon.

While Reverand Elijah Craig may have been the father, some say that he was credited by members of the Anti-Prohibition lobby who wanted to pin the creation of Bourbon on a religious man. Many believe that Bourbon's origins lie in the journey to its main market, New Orleans. It is thought that some casks were charred to guard against impurities on the long journey. Whatever the truth of the matter, the natural sugars from the charred wood are essential to the flavour.

It is generally accepted that Bourbon was perfected between 1825 and 1845 by Dr. James Crow, who is credited with originating the sour mash method.

straight bourbon

'Straight' is the term for the use of a majority percentage grain, such as corn, rye, etc., in the mashbill of a Bourbon. Straight whiskey must leave the still at no more than 80%abv and must be casked at less than 62.5%abv. (However, whiskey can increase in strength when aged.) Keeping the distillation proof low ensures more flavour stays in the spirit.

Straight whiskey must be aged for a minimum of two years in new charred oak casts. If aged for less than four years, the whiskey must show its age on the label (steer clear of 2-3 year old whiskies). No colouring or flavouring is permitted to be added to straight whiskey. If the corn content exceeds 80% then it becomes Corn Whiskey, although this is then matured in aged, uncharred barrels.

where can it be made?

Bourbon can be made anywhere in the U.S.A., but only Kentucky Bourbon can advertise the state where it is made. Thus there is no Bourbon with Tennessee on the label. The reason for this is political: Kentucky had more senators than its neighbours and blatantly used its voting power to achieve this preferential outcome.

production method

A whiskey distiller must first determine the 'mash bill', essentially the recipe of different grains from which the whiskey is to be made. In the case of Bourbon this will consist of a minimum of 51% corn (usually 70%) with the balance made up by 'small grains', usually malted barley and either rye or wheat. Rye produces a heavier whiskey such as Old Grandad, wheat a lighter one such as Maker's Mark. Limestone water is then added to the grain and the mix is cooked in a pressure cooker to produce a 'mash'. The cooking reduces the starch present into sugars which ferment. After the addition of yeast and sour mash (see below), the mash is left to ferment for 3-4 days to turn into 'beer'.

sour mash

Approximately 25% of the mash from the previous batch is held back and added to the next batch. This contains some of the yeast needed for fermentation, helps to keep out wild yeast and ensures a consistency between different batches.

This is known as the 'Sour Mash' process and is the normal method of production in all straight whiskies, though only a few state this on the label. This method is thought to have been perfected in the early half of the nineteenth by Dr. James Crow; a Scottish distiller in Kentucky. 'Sweet Mash', where a new batch of mash is used each time, is no longer used.

bourbon distillation

The sweet beer like-liquid is then distilled. In some factories, this is a huge industrial process employing Coffey stills. In other, smaller, businesses a cross between a pot and Coffey still is used. The beer is distilled twice, usually once in a column still which takes the strength up to approximately 50%abv and then again in a 'doubler' which continues to remove fusel-oils and impurities and increases the strength to around 63%abv (few Bourbons are triple distilled). The whiskey is then casked unless the spirit is to be a Tennessee Whiskey, in which case it would be filtered (see Tennessee whiskey).

ageing bourbon

The most important part of the creation of any Bourbon is the unique method of ageing. Bourbon must be aged for at least two years in a charred oak barrel that may not then be re used for the same purpose. (There are four degrees of charring.) Whilst maturing, the whiskey absorbs the vanilla and caramel flavours from the charred wood.

The large sheds in which the barrels are kept are dispersed around the countryside. Different manufacturers paint their warehouses various colours to affect the heat imparted by the sun. Black, brown, cream and red are the popular hues. During the summer, the sun's heat will be retained in the barrels so that in winter the temperature will be warmer inside than out. The barrels at the top of the bonded shed will get more heat than those on the bottom, affecting the rate of the spirit's maturation inside. It is common to blend from barrel to achieve consistency.

Some warehouses are artificially heated to increase the number of cycles a year. When the wood expands with heat the whiskey seeps into the wood; when the temperature drops and the wood contracts the whiskey is forced out of the wood. This action is referred to as a cycle. Mother Nature provides around four cycles per year - some distilleries obtain around 11 cycles per year which gives the whiskey more flavour and colour.

The differences in cask position and the different degrees of charring create variation in single barrel and small-batch Bourbon. The single barrel whiskies drawn from one cask tend to have no age statement as the distiller will keep sampling the contents to find when the spirit has reached the appropriate maturity. Normally barrels from the same year will be dispersed amongst several different buildings. The loss of a whole year's batch of whiskey would be an economic disaster and this dispersal lessens the risk. The 'whiskey belt' is unfortunately in a tornado plagued area of America so such a calamity is not unknown.

The barrels are kept in bonded warehouses and government stamped. A revenue must be paid twice yearly on each barrel. After use the barrels are not discarded, but are sold on for other whiskey ageing, such as Scotch.

small batch

Special attention is currently being paid to 'small batch' whiskies which are bottled from casks in one section of the warehouse, or even from an individual barrel. This category is still to be recognized in law and the many different producers have not agreed, and probably never will agree, what constitutes a 'small batch'.

Whilst small producers may produce small batch bottling from less than a dozen casks, larger volume small batch Bourbons are usually made by taking selected casks from specific areas of the warehouse which are then blended together to achieve a taste that is consistent without being blamed.

tennessee whiskey

Whilst sharing many similarities with Bourbon production, there is an additional process in the making of Tennessee Whiskey which stops it being called Bourbon. Prior to being cased the spirit is filtered through finely ground maple charcoal. This extra procedure, the 'Lincoln County Process', was invented in 1825 by Alfred Eaton, a distiller in Tennessee. It removes fusel-oils to produce a lighter (technically purer) spirit, adds to the flavour and increases the depth of colour. The only two remaining Tennessee Whiskies (George Dickel and Jack Daniel's) are made in this way.

Some bottles of whiskey other than Tennessee whiskey have the words 'charcoal filtered' on the label. This refers to filtering after ageing with active charcoal, a process that can remove flavours from the whiskey. Tennessee whiskey also goes through this process after ageing, but it's the quite different 'Lincoln County Process' that adds to the flavour.

Reprinted with permission from CLASS magazine.