Storage of Whisky Casks

Why is barrel aging so important for whisky?

Storage in wooden barrels (for at least 3 years) plays a decisive role in the quality and character of every whisky, because only through appropriate barrel aging over many years can the typical whisky aromas develop.

In addition, the mouthfeel and alcohol impression improve with the duration of maturation, as the interaction of the distillate with the wood and the penetrating oxygen initiates the magical maturation process. At the same time, some of it is lost to the environment through evaporation - the so-called Angel's Share. However, this is indispensable for maturation: "Where nothing goes out, nothing goes in," meaning that alcohol and water escape (evaporate) from the barrel and oxygen enters. Oxidation by oxygen is an essential part of maturation.

What characteristics are important for barrel storage?

The maturation process in wooden barrels is very crucial in whisky production, which is why the barrel warehouses, their climate and structural condition are of vital importance. Only in a suitably designed barrel warehouse can maturation lead to the desired results.

What is important to us when storing our barrels:

• Mild climate - no enormous and, above all, rapid temperature fluctuations between day and night or between seasons. A stable temperature prevents leaks in the barrels.
• Mitigation of extreme weather - no exposure of the barrels to extremely hot or cold temperatures in summer and winter, which also has a positive effect against leaks and too high an Angel's Share in summer.
• Good ventilation - a certain air exchange is desired. This supplies fresh air and thus fresh oxygen for maturation, while air saturated with alcohol and water is removed from the warehouse. IMPORTANT: Ventilation only to the extent that the humidity does not fall below approx. 75% relative humidity, otherwise it would be too dry for the barrels.
• Good air quality around the warehouse and in the warehouse building - direct influence on the quality of the whisky through oxygen absorption.
• Security of stored barrels - protection against fire, flooding, theft, sabotage, etc.

Our warehouse: St. Kilian Bunker City!

Our external warehouse - the St. Kilian Bunker City - fulfills all these requirements. The former NATO ammunition bunkers are spread over an area of almost 80 hectares and are the perfect solution to meet our demands for a perfect whisky warehouse.

Why is the bunker so well suited as a whisky warehouse?

Each bunker is perfectly secured against water penetration; the terrain is sloped and carries large amounts of rainwater downhill, away from the facilities. Not only is each bunker secured, but the entire area is also fenced and monitored according to NATO standards, ensuring optimal protection against burglary or sabotage. In addition, the wide distances between the bunkers provide safety against fire damage, and a corresponding lightning protection system on each bunker protects against lightning strikes. As mentioned above, ventilation is also a central issue; the bunkers are forcibly ventilated through existing steel chimneys – perfect for maturation.

We are located in the beautiful Odenwald forest, isolated from the nearest village. Each bunker is covered with earth, grassed, and partly overgrown with trees. This has a perfect effect on the microclimate and air quality, because the insulation of the earth and the climate regulation in the forest prevent extreme temperature peaks in summer or winter. Very consistent and moderated conditions in the warehouses are the positive consequences of the bunker's characteristics.

The bunkers are made of concrete, and the ceilings, walls, and floors have not been treated or painted. Due to the untreated structures, the microclimate inside the bunker itself is perfect for whisky storage. The barrels are stacked in steel racks a maximum of 3m high. This results in good homogeneity in the bunker, because the higher the storage, the more varied the degree of maturation from the topmost barrel compared to the bottom barrels.