By: Kris Bohm – Owner of Distillery Now Consulting
The process of putting distilled spirits into barrels whether it be for transportation or maturation is a centuries-old process.
There is a wonderful transformation that occurs when spirits spend time in a wooden barrel. Among the general public there’s a perception that time is the only factor that matters when it comes to the quality of a matured spirit whether it be whiskey brandy or rum. It is known among distillers that age is only one of a multitude of factors that actually determine the flavor of the spirit when it comes out of the barrel. In this article I’ll break down some of the most critical factors that affect the transformation of spirits in a barrel. Lets jump in and break down the barrel aging and the best practices for it.
Distillation and Congeners
Distilling is the first step that will affect how a spirit matures. In the process of distilling the heads and tails cuts that are made by the distiller have a massive effect on the character of the spirit. Whiskeys that are distilled with very tight cuts when matured for a long time will often come out of the barrel rather flat and often have a strong oak flavor. Whiskeys that are distilled with very broad cuts with a considerable amount of tails and oils left in the distillate often need a long time to mature but also will have much more depth than complexity to the finished whiskey.
Barrel Choice
When it comes to aging whiskey such as bourbon or rye in America it is a legal requirement to use new American Oak. There are still a multitude of options within the legal requirement of new oak. Barrels can come in many different sizes and also char or toast levels. All of these have a strong effect on the change in the flavor of the spirit. It is a bit of a misconception that smaller barrels tend to mature spirits quicker. Smaller Barrels have a larger surface area ratio to the amount of whiskey in the barrel. This increase in surface area forces the whiskey to take on more intense oak characteristics faster. While a small barrel may give the impression of a more mature spirit faster it is often overly tannic and not as well balanced in flavor as a whiskey that comes out of a full size 53 gallon barrel.
Storage Location
When barrels are being stored (commonly for several years) the location where the barrel is stored has a strong effect on the flavor of the whiskey. The environment where a barrel is stored also affects how much loss (evaporation) will come out of the barrel. Temperature range and humidity are two critical factors to consider when selecting a location for storing barrels. Barrels that are stored in a location that is relatively hot will typically see higher rates of evaporation compared to barrels that are stored in a colder location. The same goes for humidity when barrels are stored in an area that is humid they typically see much lower rates of evaporation then barrels stored in areas that are dry. This is not to say that the ideal location to store barrels is cold and humid as barrels stored in this type of climate such like the climate of Scotland have very slow maturation rates.
It is important to consider the overall climate and how it can be affected or changed to better control the maturation of spirits. There are many distilleries located in colder climates that will heat their barrel storage warehouse to help speed up the maturation of the spirits. Some distilleries even go so far as to heat and humidify the air in a barrel storage space to speed the maturation while minimizing the evaporative loss of spirits from the barrels.
Air Flow
While temperature and humidity are two of the most important factors in barrel maturation, air currents also play a role in how spirits mature. It has been found that barrels that are stored in drafty buildings or near doors and windows that see air flow around barrels will often have much higher evaporative losses compared to barrels stored in a location that has minimal air flow or air exchange around the barrel.
What Happens in the Barrel
The maturation of spirits within a barrel is said to be both an additive and subtractive process. It is additive in that characteristics from the wood and the charring of the wood add tannins and lignins to the alcohol. The process of maturation in a barrel is also subtractive in that some of the less desirable components of distilled spirits evaporate out of the barrel as the spirit matures. When alcohol is placed within a wooden barrel the alcohol reacts with oxygen and is partially transformed into aldehydes. The continual exposure of the aldehydes to oxygen eventually transforms them into acids. These acids undergo esterification in the maturation process which can change the mouthfeel of the whiskey. This change adds to the complexity of flavor within the spirit.
Barrel Management
Creating consistent world class spirits is only possible through excellent barrel management. This is achieved through concise record-keeping and traceability. All barrels should be clearly labeled and identified. Clear identification allows the management handling the barrels to know the contents, age and trace information back to the distillation records of the spirit. There are great modern ways and technology to track and identify barrels but good record keeping of every time a barrel is sampled and or moved can be the difference between good and great spirits.
Age Statements
The statement of the age on the label of a bottle of whiskey will often be one of the defining factors in the perception by the consumer of the “quality” of the spirit. This perception can be extremely hard to overcome and will often push distillers to age their spirits to an age that is perceived as high quality.
To consistently produce a spirit that is of a certain age can be challenging or in some cases even impossible if there is not enough distilled spirits that is of the acceptable age to meet the age statement on the label. Consideration should be given early on to the quantity of barrels being produced to ensure adequate stock of spirits when the time comes to sell those aged spirits.
Pricing Modeling
Careful consideration and planning should be given to the expected final retail price of the spirits you intend to age in barrels. Nothing could be more detrimental to launching a new brand than being priced far above comparable competitors due to your cost of manufacturing being higher than anticipated.
A cost analysis must be done before investing money into aging spirits to ensure that the all cost of manufacturing including anticipated evaporative loss can be recouped with a profit in the manufacturing of those distilled spirits.
Building Your System
The perfect way to effectively mature and manage barrels of spirit is going to be different for every person. It takes a considerable level of planning preparation and continual execution to create consistent spirits. Planning your process before you start it and creating a system to effectively implement the plan is the best way to ensure when the time comes to bottle and sell your spirits the quality of the product will be top notch.
