After the raw materials of whiskey have been ground, saccharified, fermented and other processes, the mash used for distillation is in a paste state. These paste mash are added to the distiller, and the ethanol and other trace components are separated by heating, which is the new make of whiskey. Anyone who has cooked porridge in a pot knows that when cooking porridge, the rice grains or other grains in the pot mostly sink to the bottom of the pot. If the heat is not well controlled or the pot is not stirred frequently, the grains at the bottom of the pot will become mushy. Once the pot is mushy, the rice will have an unpleasant mushy smell. Whiskey distiller, especially the juice distiller for distilling mash, is mostly large in size. The mash of a single distillation may reach several thousand liters or even tens of thousands of liters. How can such a large distiller be controlled to prevent the bottom from becoming mushy and ensure that there is no discordant mushy smell in the whiskey?
The distillation of malt whiskey is divided into two main types according to the heating method: direct fire heating and indirect heating. Direct fire heating is to use open flames to directly heat the distiller to distill the mash. Indirect heating is to use a boiler to heat water into steam, and then transport the steam to the inside of the distiller through pipes to heat the mash. Early whiskeys were heated by direct fire. After the 1960s, indirect heating gradually replaced direct fire heating and became the mainstream operation method. One of the main reasons for this change is to prevent the bottom from getting sticky.
When heating with direct fire, the heat will first reach the bottom of the still and then be transferred to the mash. This method causes the bottom of the still to be hot first, and the sugars, proteins, wheat husks, etc. that are precipitated at the bottom will easily become mushy when encountering high temperatures. When heating indirectly, the steam pipe is located inside the distiller, and heating the mash directly will not easily cause the bottom of the pot to become mushy due to the high temperature at the bottom. Therefore, it can be said that indirect heating technology has largely solved the problem of mushy bottom.
Before the indirect heating technology was adopted, how did whiskey prevent from getting stuck during distillation?
In fact, there are many ways. The first is to clean the still after each distillation, and completely remove the sugars, proteins and other substances attached to the still, which is equivalent to washing the pot after cooking. Of course, a clean pot is less likely to get stuck than the pot used last time. In order to better clean the still, a scraper will be installed inside the still to scrape off the substances attached to the pot, which is equivalent to using a pot brush to brush the pot, which is of course cleaner than washing the pot with bare hands. When the scraper scrapes off sugars and other substances, it is inevitable that part of the copper on the still will be scraped off. Over time, the still will become thinner and thinner. In order to extend the life of the still, the overall thickness of the still is not the same when it is made. The parts with greater consumption are thicker, and the parts with less consumption are thinner. For example, if the pot wall is 10mm thick, the bottom of the pot may have to be 16mm thick. This will increase the service life of the still as much as possible.
In addition to extending the service life of the distillation pot, increasing the thickness of the bottom of the pot also has a certain anti-sticking effect. Taking cooking as an example, the thicker the pot, the slower the heat conduction, and the less likely it is to stick when cooking. The thickened bottom of the distillation pot can also slow down the heat conduction and prevent sticking.
In addition, the shape of the distillation pot also has a certain anti-sticking effect. Regardless of the shape of the distiller, whether it is onion-shaped, straight, or lantern-shaped, the bottom of all distillations is not straight, but has an arc, slightly curved upward. It is said that this design is to better discharge the lees after distillation, but in addition to this, the arc-shaped bottom can disperse heat, which will also prevent sticking. The large curved iron pans used in rural areas are less likely to get stuck than frying pans. The pans that professional chefs use to cook are all smaller versions of large iron pans. They generally don't use frying pans. A big part of the reason is that a pan with a small bottom and a curve heats more evenly.
In addition to modifying the distiller, pre-treatment of the mash can also effectively reduce the bottom sticking. Generally speaking, when the mash is put into the distiller for distillation, it is not at room temperature, but needs to be heated in advance, about 60°C. Heating the mash can reduce the temperature difference between the mash itself and the distiller, reduce the cracking of sugars and proteins caused by sudden contact with high temperature, and can also play a role in preventing sticking to a certain extent.
In summary, there are many anti-sticking measures during whiskey distillation. Through the superposition of various means, the risk of sticking during distillation can basically be effectively reduced, thereby reducing the risk of unharmonious sticky taste in whiskey.
