Theory & Process

Through our research, we have developed the Jensen reactor. The current model is the Jensen Reactor Mk I. We don’t add weird flavour extracts or synthetic elements. We alter the physicochemical state of the whisky. The key for good whisky is two things: extraction and transformation. The plot and the twist.

If you would like to dive deep into the chemistry of aged spirits, here you can check which compounds of interest we focus on during research. 


At the beginning of the process previously used or new barrels are being disassembled. Next, whole barrel staves are loaded into the Jensen reactor, while other parts are chopped into chips and used in an ultrasound casket. We carefully select the types of barrels used for each product and are able to compose mixed sets of different barrel staves.

By the combination of ultrasound and heat exposure, we accelerate the extraction of precursors and flavour components as lignin, polyphenols, short and medium chained fatty acids, hemicellulose etc. Some components are important for the later transformation while others give direct flavour to the spirit.


The key flavour of aged whiskies are esters. Esters are formed by condensation of alcohol and organic acid (Carboxylic acid). The most abundant alcohol in whisky is ethanol and therefore most of the esters formed are ethyl esters.

However, other alcohols are also present in the spirit, they are collected from the tails fraction during the distillation process (butanol, propanol, amyl alcohols etc.). Additionally, depending on the distillate and the barrels, different organics acids are being extracted or created via chemical reactions.

The process of esterification depends on the type and strength of alcohol and organic acids. This is the beauty of aging, as the results vary so much depending on the quality of the barrel and the spirit.

Jensen reactor, while other parts are chopped into chips and used in ultrasound casket. We carefully select the types of barrels used for each product and are able to compose mixed sets of different barrel staves.


The production begins with careful selection of New Make, which is a base for our future aged spirit. We are supplied with craft, high quality Scotch distillate and match it with precisely selected oak barrels.
It’s important to know that New Make is not entirely “clean” of other congeners (compounds created during distillation that are not ethanol and water). There are hundreds of different congeners in whisky with different properties and flavour profiles. 

This includes compounds desired by distilleries: esters, aldehydes and higher alcohols, but also sulphurs and acids which are generally unpleasant. The highest quality of base spirit lets us focus entirely on the maturation process, which is the crucial step in the whisky production. Aging vastly distinguishes raw spirit from the final whisky product due to reactions which occur between distillate, congeners and barrel wood components.

Our current reactor Jensen Mk I, employs 6 different acceleration aging techniques, combined in one production unit.
That is:
– elevated operational temperature,
– high ultrasound wave extraction,
– inorganic acid catalysator,
– increased wood to liquid ratio by addition of both oak chips and oak staves,
– controlled micro-oxygenation process,
– usage of flow rate and constant circulation of the liquid,

EtOH Reactor


Now, let’s dive deeper, what each of those parameters does for our final product:

Elevated temperature helps to break the cell walls of the wood and in consequence release a higher amount of soluble phenolics, colour compounds and ellagic acid. Additionally, higher temperature decreases the activation energy of the reaction which in consequence leads to an increased reaction rate.

In an ultrasound system, sound waves cause periodic changes in air pressure. Sound is transmitted through a medium by inducing the vibrational motion of the molecules through which it is travelling. During the ultrasound process, some energy is lost through conversion to heat, and the rest can produce cavitation. Ultrasound cavitation enhances the oak extraction procedure. 

Inorganic acid catalysator, similarly to elevated temperature can decrease the activation energy of the reaction. More precisely it increases the rate of one of the most important reactions in whisky production – esterification.

Usage of oak chips in addition to oak staves provides much higher wood compounds extraction than classic barrel-ageing at the same period due to its much higher surface-to-volume ratio.

The micro-oxygenation process improves spirit by providing a crucial component (oxygen) for many reactions in the closed system. Operating in a closed system limits oxygen exposure, adding the gas mimics the natural process of aging.

The optimal flow rate provides sufficient contact time between wood and spirit and ensures proper mixing during the production time.

After 7 to 14 days of applying the above-mentioned parameters, we’re ready to send you a bottle of this novel product.