Traditionally, American whiskey uses a secondary distillation method to obtain new wine. The pot stills used were brought all the way across the Atlantic to the New World by colonists, or they were built directly from simple local materials. Interestingly, when a large number of Irish immigrants came to the United States in the mid-18th century, the whiskey they made using native crops was also spelled whiskey, but it was only twice distilled instead of the triple distillation popular in Ireland, perhaps because of the grain raw materials. Because of the relationship, maybe the life of immigrants is difficult and I don't want to spend the cost to do it again.
But when the Coffey stills on the other side of the Atlantic were already maturely used by grain whiskey distillers, the use of three-chamber stills (three-chamber stills) was also popular in the United States at the same time.When the U.S. Department of Revenue studied the tax regulations on whiskey aging in 1889, 13 of the 16 rye whiskey distilleries used three-tank stills, of which 9 were wooden and 4 were copper. The output ranged from Ranging from 2,000 to 15,000 gallons, it is clear that the three-tank still is still the first choice for rye whiskey manufacturers. The shape of this still is similar to a cone that gradually shrinks upward. The interior is divided into three tanks of approximately the same volume by wooden or copper plates. The heating steam pipe is set up with the bottom tank, and the extraction pipe is set up at the top tank. Copper pipes are set between the tanks to allow the steam to rise, and a valve is set at the bottom of each tank to allow the wine to fall to the lower level.
Before the introduction of large and expensive continuous stills, the three-tank still was used roughly from 1850 to the Prohibition period. It was an intermediate product between the pot still and the continuous still, used to make up for the pot still. Still is not producing enough. After Prohibition, the three-tank still disappeared from the history of American whiskey. Until recent years, a handful of one or two craft distilleries, such as the Leopold Bros. Distillery in Denver, have been digging through dusty historical documents. This unique still was rebuilt, and it is said that it can distill more oil.In any case, among today's large distilleries, only Wofford uses pot stills for triple distillation. All other distilleries have abandoned traditional distillation equipment and technology. Although they are still distilled twice, the first time is in The first is in a continuous still (or beer still), and the second time is in a single tank still. For the latter, the reason why we are reluctant to call it a pot still is that this type of distiller is divided into two types, including one that inputs low-alcohol wine (doubler) and one that inputs steam (heavy machine thumper), but it is still a continuous type. input rather than traditional batch practices. Using this improved secondary distillation, each bushel of grain can produce about 5 degrees per gallon of new wine, which is 400-450LPA/ton when converted to metric, which is slightly higher than the 390-420LPA/ton of malt whiskey.
Currently, most of the stills used by major distilleries are produced by Vendome Copper & Brass Works in Kentucky. They also build pot stills and hybrid stills (hybrid stills, on pot stills) that are popular in craft distilleries. Install distillation columns for batch distillation), and all other distillation equipment. When they design a still for a new distillery, they don't just consider short-term production capacity, but work with the owner to plan a longer-term operating model. And based on their experience, although many small distilleries like to customize pot stills, There are also more and more emerging wineries that like to customize pot stills, but there are also more and more emerging wineries that use smaller-sized continuous stills because they can provide more consistent distillation quality.
Continuous distiller
Scottish grain distillers generally split this type of distiller into two, called a Rectifier column and an Analyzer column. After fermentation, the wine juice is first introduced into the rectification column for preheating, and then is processed from the top. After entering the analytical column, the obtained vapor is returned to the bottom of the distillation column, passing through the multi-layer distillation plate to finally obtain new wine with an alcohol content close to neutral alcohol (defined by Scottish regulations as 94.8).The beer still used by Meiwei usually has only one, and its structure and function are the same as the analytical column. However, due to the relatively small number of distillation plates installed inside, the number of distillations carried out is naturally relatively small, and the final alcohol content is about 120 to 130proof ( Low alcohol wine (about 60-65%) can retain more flavor substances.
Dimensions of stills vary due to different purposes. Generally, small craft distilleries mostly use slim stills with a diameter of 12 inches to 24 inches (about 0.3 to 0.6 meters), such as the modern-style Rabbit Hole Distillery in Louisville. Among the large distilleries, the beer still used by Meg is the smallest, with a diameter of only 36 inches (about 0.91 cm), while the largest bourbon whiskey distillery, King Beam, has a still with a diameter of 72 inches (about 1.8 cm). feet), produced Jack Daniel's, the largest distillery in Mayway, uses a beer still with a diameter of 76 inches (about 1.93 meters), but it is not as good as the largest still in the United States owned by Buffalo Wizard, with a diameter of 84 inches (about 2.1 meters).
The internal equipment of these distillers can be illustrated by taking the Meg Distillery as an example. In the 37-foot-long (about 11.2 meters, 4-story high) still, there are 13 layers of copper distillation plates. Each layer of distillation plates is equipped with about 200 ventilation holes. It is also set up to allow the ale to flow downwards. The diversion tubes are cross-spaced on the left and right. The upper end of the guide tube protrudes a short distance from the distillation plate, and its function is similar to a weir. The beer on the plate must accumulate to a certain height before it can cross the weir and enter the tube, and then flow to the next layer.
The actual approach is as follows:
1.The heated ale is fed into the still from above the first distillation plate and spreads across the distillation plate. Although there are 200 openings on the plate, the steam pressure below the openings prevents the beer from dripping. After it accumulates to a certain height, it flows from the diversion holes along the diversion tube to the next distillation plate.
2.High-temperature steam is input from below. When the steam hits the beer on the distillation plate, it will take away part of the relatively volatile alcohol and other substances, and generate a force for the beer to flow (similar to the common tables in amusement parks). On the air hockey game machine, the air pressure from the small holes on the table can hold the round hockey ball and slide it at will). As it evaporates upward layer by layer, the alcohol concentration becomes higher and higher, and the alcohol concentration of the ale flowing downward becomes lower and lower. At the lowest point, since the alcohol content is close to 0%, the solid and liquid states can be separated after collection. The solid is used as animal feed, and the liquid is called backset, which is mixed with the next batch of grain saccharification water, which is the sour mash process mentioned above.
3.The alcohol vapor rises to the second layer at the top, and most of it will be directed to the condenser. After condensation, it will be a low-alcohol wine with an alcohol content of 120proof (60%), which is stored in the temporary storage tank. A small part of the lighter gas will be It is pressed into the topmost copper compartment through the central hole, but because it has nowhere to go, it condenses and flows back downwards, and then continues to distill.
Different wineries have different still heights and number of distillation plates. The beer input port is mostly located in the center or 2/3 of the height of the distillation column. The input steam temperature is close to boiling 202~212℉ (95~100℃) , the output alcohol vapor temperature is 172~185℉ (78~85℃). As long as the position of the output port is adjusted, the low alcohol content set by the winery can be obtained. Taking Meg Winery as an example, if the output position is moved down one level, the alcohol content of the low-alcohol wine will be lower than 120proof.
The beauty of the continuous distiller is that when the distiller's beer continues to flow in from the input port, and steam with a fixed temperature and pressure is also continuously input from the bottom, the entire equipment is like a closed system. After operating for a period of time, it will reach a stable state. The input alcohol content (= input rate × alcohol content of beer) is equal to the output alcohol amount (= output rate × alcohol content of low-alcohol wine). As long as it is continuously monitored, new wine can be obtained continuously.
However, because the distiller's beer contains a lot of solid matter, which is gradually pushed into the distillation class as the distillation time is extended, the distillation efficiency is therefore reduced, and the distillation must be stopped at intervals for cleaning.Before shutting down, first switch the beer input valve to hot water, and carefully check the alcohol content of low-alcohol wine. Once it is lower than the collection standard, pour all subsequent liquids into the temporary storage tank, and stop inputting steam to wait for the solid state at the bottom. After all the materials have flowed clean, the input of hot water can be stopped and the shutdown operation is completed.
When restarting operation, hot water must be injected first to preheat all pipes and distillation plates in the distillation column, then steam input is started, and then the beer mixed with the last batch of wine tails is input. Since the alcohol content of the newly obtained wine is not high, it is first introduced into a temporary storage tank and intensively tested. Once it reaches the alcohol content standard expected by the winery and the system reaches equilibrium, formal collection begins.
Doublers and Heavy Hitters
The next question is, why not just use beer steam to get the expected new wine, instead of having to go through a lot of troublesome condensation and re-distillation? This question must also be answered from the structure and principle of the beer (continuous) distiller. Each layer is equivalent to a small distiller. Due to the relatively high volatility of alcohol, the rising steam will separate the beer in each layer. The alcohol is carried upward, so as the altitude increases, the alcohol content in the steam also increases. But for those in the winery industry, they all have the ideal alcohol content of new wine, which is probably between 125 and 143 proof (62.5 to 71.5%, which is about the same alcohol content as twice-distilled new wine in Scotland).But the problem is, if the steam has reached 120proof on the 12th floor of the distillation plate, it may exceed the ideal alcohol content on the next higher level. The only way is to export the 120proof steam, and then use the pot still Distill again.
As for how to use a doubler to increase the alcohol content, such as 10proof (Jinbein: 125proof to 135proof; Meig: 120proof to 130proof)? This question may seem a bit unbelievable to readers who are familiar with Scotch whiskey, because in our stereotype, the alcohol content of low-alcohol wine after primary distillation is about 25 to 30%, and after secondary distillation, it can be directly raised to 65 to 70%. %, how to control the small 5%? Fred Noe, the master distiller of Jinbin Distillery, can get the desired alcohol content.
So we still have to go back to the underlying principles. The principle is that when the water/wine ratio mixture is heated to a certain temperature, the mixture can be in a range where gaseous state and adsorption coexist. At this time, the alcohol concentration in the gaseous state can be increased to a specific value; if you just want to slightly Increase the alcohol concentration, for example, 5%. So Fred Noe's instructions are very clear. Since the low-alcohol alcohol is fixed at 125proof (imagine the water/wine ratio is fixed), you only need to fix the fixed temperature and continue to input the low-alcohol wine to be sustainable. Take out the 135 proof new wine.
From the above description, we can know that although the shape of the doubler is a single pot type, it does not use batch distillation. Therefore, it does not take out the heart of the wine, and of course there is no head or tail. Instead, it condenses the low content of the beer distiller. Liquor is continuously input into the pot, and steam at a specific temperature is also input (in terms of indirect heating). ), in this way, new wine flows out continuously like a waterfall, but the function and structure of the doubler can be more complicated. Since the beer stills in a small number of wineries are made of stainless steel, copper doublers are used, or A copper mesh adsorption layer (copper) is installed on the top of the distillation passage. sponge), called deminster, allows the distillation gas to react with copper, adsorbing and filtering out heavy oil molecules that the winery does not want, and producing cleaner new wine.
As for the heavy hitter, which most people don't understand, it has a longer history of use than the doubler. The most original design is very simple, as shown in the figure below. First, the low-alcohol wine that is partially condensed into liquid is put into the thumper, and then the pot still is heated for the first distillation. The generated steam is introduced
into the thumper. Then the pot still is heated for the first distillation, and the generated steam is introduced into the bottom of the thumper. The residual heat energy of the steam is used to evaporate the low-alcohol wine for the second distillation. The distilled gas is sent to the worm barrel condenser for condensation, which is the new wine, while the gas distilled for the first time is partially condensed into low-alcohol wine and retained at the bottom of the thumper. In this way, the secondary distillation operation is completed.
A thumper functions like a spirits still, but requires no additional heat, and low-alcohol liquor does not need to be condensed, so energy costs are lower. If the heat of the steam from the pot still is strong and there is sufficient preheating after passing through the first hammer, then the second hammer can be connected in series for a third distillation, or even a fourth distillation. This simple distillation method is popular in rum distilleries near the Caribbean and early American moonshine. For them, they only need to prepare a metal still heated by direct fire, and the hammer directly uses wooden barrels. There are two holes dug in the lid of the bucket, one for entry and one for exit. In addition to using local materials, since wood is less likely to dissipate heat, it can maintain heat energy better than metal buckets.
After all, the above-mentioned simple secondary distillation method cannot be compared with the continuous spirit still. The main reason is that the alcohol content cannot be increased too much, and the flavor is more complicated. However, if it is connected in the form of a thumper after the beer still, The disadvantages turn into advantages. When low-alcohol wine vapor is continuously input, new wine with a slightly higher alcohol content can be continuously output.
