Maintaining optimal temperature distillation to yield a crystal clear brew without the odor and harmful impurities. This is one of the most important stages of brewing, not knowing the bases which it is impossible to expect a good result. Without observance of technology of distillation even in the best of Braga get a bad brew.
Boiling point and volatile impurities
The most common misconception among beginners moonshiners says that the impurities evaporate in proportion to their boiling point. In fact, this is completely wrong: the volatile impurities, i.e. their ability to leave the boiling liquid, has nothing to do with the boiling points of these impurities.
Consider the classic example of methanol and isoamylene. Let in the cube is flooded with raw materials of the following composition (see table).
|The composition of the distilled liquid||The boiling point of substances (°C)||The ratio in solution (%)|
Bring the mixture to a boil (temperature in Cuba is about 92 °C) and will select a small amount of the distillate to the composition of the fluidized raw material is almost not changed. What will be the composition of the distillate selected? For water and ethanol the concentrations can easily find the curve of equilibrium or tables: the alcohol concentration will increase from 12 to 59%.
The curve of equilibrium of water and ethanol
To determine the change in the concentration of impurities, we use the graph of the coefficients of rectification (fortress in percent of volume on the upper horizontal axis).
At the castle of raw materials 12% rectification coefficient (Kr) of methyl alcohol equal to 0.67, and Cu of isoamylase is 2.1. Hence, the content of methanol in the selection will decrease and isoamylase – will increase twice. The result is.
|The composition of the distilled liquid||The boiling point of substances (°C)||The ratio in solution (%)||The change in the number|
|in raw materials||the distillate|
|water||100||86||38.2||less than 2.2 times|
|ethyl alcohol||78||12||59||more than 4.9 times|
|methanol||65||1||0.67||less than 1.5 times|
|isoamyl||132||1||2.1||more than 2.1 times|
The second table demonstrates the independence of the speed of evaporation of impurities on the temperature of their boiling point. Methanol with a boiling point of 65 °C slowly leaving the cube than IsaMill with a boiling point of 132 degrees.
This is because the concentration of these impurities is small. If the amount of methanol and isoamylene was comparable with alcohol and water these substances would declare his right to the evaporation in the amount corresponding to the difference in their boiling points, and become full-fledged components of the solution.
The evaporation of impurities in a concentration of less than 2% depends entirely on the force with which their lonely molecules held water-alcohol solution (the predominant composition of the substances). This can be compared to what dad and mom don’t ask a child how fast to run for the bus – take hands and gallop.
And with impurities. When in solution a little methanol molecule surrounded by a crowd of water molecules, they easily held her next to him. Since a molecule of methanol is less than ethanol, then water to keep it much easier. But SEAMILL, on the contrary, is poorly soluble in water, with very weak connections. When boiling isoamyl flies out of the water faster than methanol, although the boiling temperature in 2 times above.
The study of the coefficients of evaporation or volatility of different substances and their solutions have devoted a lot of their works of Sorel. He made tables and graphs, which you can see how changing the contents of substances in pairs relative to the original solution. However, for the purposes of distilling charts and tables are inconvenient to use, so Barba offered a new estimated coefficient, called the coefficient of rectification (Cu), for which you need at a given strength of the solution is to divide the coefficient of evaporation of impurities by a factor of evaporation of ethanol.
The coefficient of rectification is also the factor of cleaning as shows the actual change in the content of impurities in relation to ethyl alcohol:
- Cu=1 – impurities cannot be removed, they are in the same amount will be present in the distillate;
- Cu>1 – in the selection of impurities will be greater than in the feedstock, this head fraction;
- Cu<1 – obtained by distillation of the distillate, the impurities will be less than the raw materials will be clean, it’s tail of fraction.
If impurities at high concentrations of alcohol have Cu<1, while at low Cu>1 is intermediate impurities. Such an absolute majority. There is also the limit of impurity, which, on the contrary, Cu>1, with high concentrations of alcohol, and low – Cu<1.
In fact, brand head or tail of impurities is not so much, most distillers are dealing with intermediate. However, if we talk about the distillation of Braga, the aroma changes during the process with 12% and below. With such concentration of alcohol almost all the impurities are in the head, regardless of the temperature of boiling: isoamyl – 132 °C, acetaldehyde is 20 °C, etc.
Impurities exhibiting tail properties, in the distillation of the mash quite a bit: methanol with a boiling point of 65 degrees and a furfural – 162 °C. As you can see here, the boiling point has no effect.
The main theoretical conclusion. Impurities are not lining up to withdraw from Cuba in accordance with the temperature of its boiling point and evaporate in the composition of the alcohol vapor in quantities depending only on their initial concentration and the coefficient of rectification.
Heating power and the temperature of the boiling point of the solution
Heating power only affects the amount of generated steam and does not alter the boiling temperature of the cube content. In turn, the boiling point of a solution depends on the concentration of alcohol in the bottoms nawalka and atmospheric pressure (see table).
The smaller fortress, the higher the boiling point of the bottoms davalki. The more power supplied, the more vapor is formed.
If the boiling mixture on the way to her refrigerator couples congenerous on the cover and the walls of the cube, or the value is negligible, then taking the shoulder straps sequentially at different banks, get them in different strength and composition of the distillate.
This is a simple fractional distillation, which can be controlled only conditionally, changing the proportions of selected fractions. No cleaning or strengthening method does not provide.
If the device is to insulate, regardless of speed selection and heating power, the output is the distillate of the same composition and strength.
If the path from the cube in the fridge the visible part of the vapour condenseries is a partial condensation.
Wall cube, cover and steam pipe continuously lose heat. These heat losses do not depend on the magnitude of the heating or selection, but only on the temperature difference between the CC content (liquid and vapor) and the ambient air.
The result is useful in the distillation process is the partial condensation of the steam, when the phlegm fall the least volatile components, which then drains back into the cube.
The same part of the couple that comes to the refrigerator, contains more volatile components than was in the original pairs. This allows you to create conditions for a more concentrated selection of “heads” and strengthen the selection.
The ratio of the weight of the phlegm to the weight of the selected alcohol is called reflux drum. Reflux drum the higher the number, the greater the strengthening and enrichment of the volatile components of the selection.
It is also important to note that flowing down to the cube phlegm is heated, causing additional condensation, but to boil not time.
If phlegm flows down to the cube for so long that the steam has time to warm it to the boiling point, there occurs another process – heat and mass transfer, in which a pair of semi-congenerous molecules of substances, and of the phlegm evaporate volatile. Evaporates and condenseries always an equal number of molecules. This process forms the basis of technology of rectification.
How to make moonshine on a conventional machine
After reviewing some of the theory questions, you can begin managing the process of distillation.
Apparatus for distillation of the classic are constructed according to the scheme of the cube fridge. Add suchoparek facilitates the selection of “body” at high speeds by preventing brythons. Cube and steam pipes are not insulated, and as we’ll find out later, is not accidental. Distillers can be different (see photo).
Fundamentally these devices only differ in the degree of partial condensation. With its small share of the device is only good for distillation of Braga, with a large partial condensation is suitable for the production of noble distillates.
Distillation of Braga
Braga need to drive fast. The main task is to separate volatilized components from the non evaporable. Power reduction at the beginning or at the end of heating is not required. When the first distillation of Braga in the alembic it is desirable to cover his dome with a cloth.
Normal sugar Braga you can select “dry” (minimum strength in the jet). In the case of fruit mash, which is planned to be aged in barrels, it is desirable to drive the average overhead of the fortress 25%. If you finish the process early, you will lose acid and heavy alcohols, which form new esters in a barrel.
The second distillation
The fortress of davalki. The optimum strength of the cubic liquid of the second stage is 25-30%. At this concentration of alcohol, the booze is fairly well strengthened, and presented as part of the head fraction. In the “tails” will be acceptable for a small percentage of alcohol, but in selecting the “body” of vodka in the cube fails to hold or require reflux drum number more than 3, which will seriously slow the process of distillation, and not every device can work in this mode.
The smaller source strength of nawalka will allow the booze during the selection of “heads” to come up with a concentration above the bottom more than two times, but the selection of “body” will be started in too small of a fortress of davalki, as a result, almost half of the alcohol will fall into the “tails” that you want to start to select at the castle of the liquid in Cuba, 5-10%.
If you increase the strength bottoms nawalka to 35-40% and more, strengthening the booze at low reflux drum numbers will not happen. In “heads” is the same brandy as the distillation residue, and at drop selection (increase in the reflux drum numbers) booze at all, will remain in the cube.
The selection of “body” will pass with less loss of alcohol at “tails”, but all remaining in Cuba, the booze gets into “the body.” Due to the fact that the volume of alcohol in the selection will decrease, the concentration of the booze will be even greater than in nawalka.
The selection of “heads”. Consider what happens when selecting “heads” on the classic moonshine. For example, VAT nawalka the fortress 25-30% boiling, and Vinokur reduced heating power up to 600 watts. The heat loss from the steam zone be 300 watts (to heat in the liquid zone, we ignore for simplicity of calculations). As a result of formed in a cube pair is exactly half will condense onto. The number will be equal to the number of phlegm, it means, reflux drum number is equal to one. The increase in heating power will lead to a reduction in reflux ratio, and Vice versa – the further reduction of power will increase it.
When organizations drop by drop selection “goals” of the system beyond the maximum reflux drum number that gives the strengthening and enrichment of the selection of volatile impurities.
During distillation, nawalka has a low fortress, and almost all the impurities are the Prime contractors. Therefore, the selection of “goals” is extremely important, it is necessary to create conditions for its successful implementation:
- always leave a large enough steam zone in Cuba, and not to chase volume Navali;
- do not insulate the cube with a lid and steam pipe of the distiller.
Getting the “body”. The sampling rate of “body” in the second fractional distillation should be moderate so as not to reduce the reflux drum.
Most household classic devices do not have sufficient capacity partial condensation, so get them acceptable cleaning “of the body” in two ways: remove impurities from the “head” or cut them with the “tails”.
When to collect “tails.” The widespread belief that the time for transition to a selection of “tails” occurs, when the strength in the jet is 40%, has a solid background.
Intermediate impurities increase its coefficient of rectification to values exceeding unity, and become easily volatile component of the pair, so, don’t turn into phlegm, and then continue to selection. Condenseries is mostly water and typically tail impurities. Partial condensation stops clean from booze alcohol, but rather enriches.
At the time of the selection of “tails” VAT temperature is about 96 °C, which corresponds to the cubic strength of about 5%. “Tails” can be selected up to 98-99 degrees in the cube, just to dry is not necessary, there are too many impurities and water.
Alternatively, I recommend to familiarize with other methods of separation of the distillate into fractionswhich are suitable even for devices without a thermometer.
On industrial distillation and rectification columns
Work with industrial and rectification columns is fundamentally different from the classic process of distillation, since there is the possibility of using the reflux condenser to adjust the amount returned to the column of phlegm in a very wide range. In the background lies teplomassoobmen. In order to raise the efficiency of the process, the column is poured the nozzle, significantly increasing the area of interaction of steam and phlegm.
The process of partial condensation, which yields a wild phlegm becomes undesirable effect of deteriorating the accuracy of regulation of the reflux ratio and separation into fractions of the height of the column. Therefore, the partial condensation is minimized by insulation of the cube and columns.
The behavior of impurities when the distillation is subject to their coefficients of rectification, but the technology has features, the main of which – the repeated evaporation and condensation of the steam on the way from Cuba to the refrigerator.
Each such perispomeni occurs in a particular area at the height of the column, called a theoretical plate. On the first 20-30 cm of the Packed portion of the column by repeated perispomeni steam gets strengthening to values above 90%. Thus impurities, departing from Cuba in the composition of the vapor during the passage of each subsequent theoretical plates will change its Cu in accordance with the fortress of phlegm or vapor in which they are located.
Therefore, fusel oil, having at the entrance to a column of Cu is greater than one, as you move up the column the CD gain is less than one, and all in fewer parisparamus, and at a certain point completely stop. The accumulation of fusel oils occurs in that part of the column where Cu=1. Above the brandy and let the alcohol for which it is in this fortress is the “tail”, and below fusel oil show head properties, and when we rise again perispomeni above. About behave all intermediate impurities.
1 —head; 2 — intermediate; 3 —caudal; 4 — terminal.
Head impurities as you move up the column, reaching all the more strengthened the vapor, as a result Cu increases. This allows the head impurities with acceleration to get to the screening area.
The tail of the impurity – quite the opposite, once in a column, with each theoretical plate sharply reduce its CD and pretty fast together with the phlegm be at the bottom of the column, where accumulated.
End impurities behave similarly: at low strength of their Cu<1, but with the rise of fortress Cu becomes larger than 1, so they do not get stuck in the column, and depending on strongholds go up or down selection.
The control column is reduced to a simple rule: you can not select the fraction with speed exceeding the speed of its receipt in the column. Methods of determining the moment when this rate begins to exceed the varied. Importantly, as early as possible to understand what is out of balance, and by reducing the sampling rate to recover it.
In the simplest version of control is possible with two thermometers:
- kubulau showing the moment of boiling of raw alcohol in the cube, go to the selection of “tails” and the end of the process;
- the thermometer located 20 cm from the bottom of the nozzle. In this zone, all transients are completed, the temperature more or less stable and reflects the processes occurring in the column with the maximum pre-emption in relation to the selection zone. The temperature increase even at 0.1 degree suggests that is taken too much alcohol – more than it enters the column, so you need to reduce the sampling rate. If you do not reduce the selection of fractionation in the column will deteriorate, and contamination established for them, the equilibrium position will move higher on the column closer to the selection.
By rectification through forced delegacii and precise control reflux drum number the output is the most volatile fraction, which can be selected sequentially. In addition, competent management column allows you to stop in her promotion of unwanted impurities in the area of selection, accumulate them until a certain time in the column or even to return to the cube.
The distillation column is not so much accurate, but rather a powerful tool for total purification of the alcohol from impurities. To obtain the noble distillates it is poorly applicable, since it requires special technology and methods. The grouping of impurities on volatile and high alcohol concentration in the column create the azeotrope indiscriminately into necessary and unnecessary, to separate them will not succeed.
When receiving the noble distillates goal is not to complete clearance of alcohol from all impurities, balanced the decrease in their concentrations with partial removal of some of the most unnecessary. Requires a device with partial condensation of the working for which the distiller separates the distillate into pieces, and then assemble this mosaic masterpiece.
When all external differences, at the heart of the distillation and rectification are the most important properties of impurity – their volatility and associated rectification coefficients. Controlling the reflux drum in a very small (distillation) or very wide (when rectifying) ranges, you can get very different product from a balanced admixture of the distillate to the pure alcohol. The main thing to understand management principles and use in each case with a suitable tool.
PS 30.03.2018 the paper has been updated and substantially revised, comments prior to this date are obsolete.