Do you prefer your rib eye rare or well done? The same question would apply to a fish or a vegetable. From the “blue” cooking point where the filet is barely heated up and cooked quickly in a pan, to those long cooking times where the customer prefers it almost “charred”, it is evident that caramelization and cooking points significantly alter the flavor of our meals. This is due to a series of chemical reactions known as Maillard reactions and, as with meats and vegetables, is a really distinctive way to mark the profile of a spirit.
Maillard reactions represent a complex series of chemical reactions that begin when a sugar reacts with an amino acid followed by an Amadori rearrangement, thus forming an amino-deoxy-ketose and subsequently, melanoid molecules. Logically, the greater the temperature gradient, the faster these reactions will be. They generally occur inside the still, and can be used to create new flavors in the distillate: by varying the composition of the liquid to be distilled, the distiller can either increase or reduce the effect of these reactions.
For example, in Cognac when the lees are distilled together with the wine, the concentration of amino acids in the still increases, which increases the reaction potential for Maillard reactions (this helps explain why Cognacs distilled with the lees have a much richer character, and are normally selected for long periods of maturation).
Of course, heating stills with a direct fire source increases the reaction potential for Maillard reactions, due to hot spots on the surface of the still pot. Logically, stills that are heated via steam injection or steam jackets are much less likely to develop Maillard reactions, since the surface of the still pot increases its temperature more homogeneously throughout the entire cooking cycle. distillation.
This is also due to the material of the still, since copper has a specific heat capacity = 0.092 cal/ g ° C. It is also possible to find Maillard reactions within the same malting system for barley, used by whisky distilleries. Although it does not have the same imprint, Maillard reactions can be observed to a lesser degree within the kilning time of the barley.
Generally speaking, the traditional kilning process starts at 50-60°C as long as the moisture in the barley is greater than 12% (also because, for smoked whiskies, peat phenols bind better under these conditions), then it is increased heat at 65-75°C until the humidity drops to 5 8%, and finally rises to 85-105°C for final drying (humidity less than 4%) and for curing, which refers to the flavor modification resulting from Maillard reactions.
Although much more modern and sustainable methods are used today for the production of spirits (kilning via hot air and stills heated via steam), alas there are distilleries that work with stills heated by direct heat, and drying processes with flames and /or peat. Famous brands such as The Glenfiddich (with a good part of its production dedicated to direct-fire stills), Craigellachie (which adds the use of worm tube condensers for less copper contact and thus maintain the imprint achieved through Maillard reactions), and even Irish distilleries like Killowen choose to include this rich and caramelized profile typical of the aforementioned reactions in the DNA of their spirits.
But, why stop there? There is a certain presence of complex sugars in the wooden staves that make up a barrel. By roasting and/or charring it, we are applying the same concept and understanding of Maillard reactions. However, the very complex interaction between the new make spirit and the cask normally occurs at room and homogeneous temperature, and therefore the exchange would logically occur between the melanoid molecules already formed in the barrel and the congeners of the spirit inside it.
As you see, the possibilities are limitless. The biggest drawback of this method of imparting different flavors in a distillate is its unsustainable nature. Today, the bulk of the world's distilleries are forced (due to costs, environmental policies, CO2 production and carbon footprint, etc.) to migrate to more ecological mechanisms to heat their stills, resulting in a loss of the influence of the reactions of Maillard in the final product. Only time and science will tell if we will be able to continue enjoying these complex and rich spirits... with a juicy steak eye, to my liking.
Slàinte mhath!