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Downcomers, Gin Baskets
What Are They?
How do They Work?
by NorCal Brewing Solutions
WARNING! Distillation of ANYTHING can be dangerous, lethal, or illegal. Please check your local laws and ordinances before running a still.
Before we dive into the details of alcohol distillation (whiskey, vodka, gin, tequila, rum, and so forth) let's examine the "generic" distilling process, used in distilling any other liquid (drinking water, essential oils, CBD extraction from cannabis, petroleum refining, chemical synthesis, and so much more).
What is the Distillation Process?
Distilling is the process of separating and purifying liquid mixtures based on differences in their boiling points.
It involves the conversion of a liquid into vapor through heating and subsequent condensation (cooling) of that vapor to obtain a purified liquid.
No matter what the desired product is, the distillation process can be broken down into 7 steps: Heating, Vaporization, Separation, Condensation, Collection, Fractional Distillation, and Multiple Distillation Runs.
Heating: The liquid mixture is heated in a still. Typically, this is a POT STILL or a COLUMN STILL - depending on the specific distilled product desired. (See section below for more details)
Vaporization: As the liquid mixture is heated, its temperature rises. Eventually, the liquid reaches its first of several boiling points. Certain components with lower boiling points start to vaporize. The vapor consists of the "volatile compounds" present in the mixture.
Separation: The vapor rises through the still, separating from the non-volatile or less volatile components in the liquid mixture. The separation occurs because different substances have different boiling points. The volatile compounds vaporize more readily and thus separate from the mixture at lower temperatures.
Condensation: The rising vapor reaches the condenser, which is a cooled surface or a set of tubes. As the vapor meets the cool surface, it loses heat and converts back into a liquid state through condensation.
Collection: The condensed liquid, now purified and separated from the non-volatile or less volatile components, is collected as distillate. The distillate represents the desired product obtained through the distillation process.
Fractional Distillation (Column Stills): Column stills add the ability to involve additional stages (called trays or plates). These trays are designed to provide multiple surfaces for vapor-distilled contact. As vapor rises through the column, it encounters trays where condensation occurs, separating the components with different boiling points more effectively. The process of separating different components based on their boiling points is known as fractional distillation.
Multiple Distillation Runs: In some cases, the distillate obtained from a single distillation run may not be pure enough, especially for high-proof alcohol or highly purified products. In such cases, the distillate can be subjected to multiple distillation runs, further purifying the liquid by removing impurities and concentrating the desired compounds.
The specific parameters and equipment used in the distillation process can vary depending on the purpose of the distillation, the nature of the liquid mixture, and the desired outcome. Factors such as temperature control, reflux ratios, and the use of packing material (in column stills) can further refine the separation and purification process.
What Basic Equipment is Used in the Distillation Process?
No matter what the end product being produced, the distillation process involves FOUR pieces of equipment: the STILL, the HEAT SOURCE, the CONDENSER, and the COLLECTION VESSEL. These four pieces are found in basic artisanal stills and industrial-scale operations.
Still: This is the main apparatus used in distillation. It consists of a boiler where the liquid mixture is heated to produce vapor. There are different types of stills, including pot stills, column stills, reflux stills, alembic stills, and more, each suited for specific purposes and producing different types of spirits or distilled products. (See detailed section on stills below).
Heat Source: A heat source is required to provide the energy needed to heat the liquid mixture in the still. Typically, an electric heater, gas burner, steam, or indirect heat sources like hot water or steam jackets surrounding the still.
Condenser: The condenser is responsible for cooling the vapor produced in the still and turning it back into a liquid form. The condenser is usually a coil or tubes through which cold water or coolant is circulated. As the vapor meets the cool surface, it condenses back into liquid form and is collected as distillate.
Collection Vessel: The collection vessel, also known as the receiver or condensate receiver, is where the distillate is collected. It can be a container or a series of containers designed to collect and separate different fractions of the distillate.
Feel free to contact Jaybird at NorCal Brewing Solutions for help in designing your basic distillation system.
What Advanced Equipment Might be Used in the Distillation Process?
Depending on the scale of the operation and the product being produced, these are some of the OPTIONAL items of distillation equipment that may be encountered:
Reflux System: In certain distillation processes, a reflux system may be employed to enhance separation and purification. The reflux condenser returns part of the condensed vapor back to the still, allowing for repeated vapor-liquid contact and more efficient separation of components. In a basic setup the reflux condenser is a column mounted on top of the still. In more advanced setups the reflux system typically includes not only a reflux condenser, but also a reflux drum and a reflux ratio control mechanism.
Thumper(s): A thumper is used in pot stills to essentially perform a secondary distillation during a single distillation run. A thumper enhances alcohol content while simultaneously refining the flavor of the product – whether it be gin, whiskey, rum, or anything else. Thumpers can be tied together in-line to perform multiple secondary distillations.
Gin Basket: A thumper essentially performs a secondary distillation during a single distillation run. A thumper enhances alcohol content while simultaneously refining the flavor of the product – whether it be gin, whiskey, rum, or anything else. Thumpers can be tied together in-line to perform multiple secondary distillations.
Pumps and Valves: Pumps are used to control the flow of liquid and vapor in the distillation process. They can be used to transfer liquid from one vessel to another or to regulate the flow rate in reflux systems. Valves are employed to control the direction, rate, and pressure of the liquid and vapor streams.
Thermometers and Temperature Controllers: Temperature monitoring and control is crucial in distillation. Thermometers can be used in various stages of the distillation process to measure and monitor temperature of the liquid, vapor, and condensate (distillate). Temperature controllers may be employed to maintain specific temperature conditions in the still, thumper, or other parts of the distillation setup.
The specific equipment used in the distillation process can vary depending on the scale of the operation, the purpose of the distillation, the nature of the liquid mixture, and the desired outcome. More complex distillation could include multiple thumpers, downcomers, trays, rectification columns, and specific filtration systems.
Factors such as temperature control, reflux ratios, and the use of packing material (in column stills) can further refine the separation and purification process.
Please note that industrial-scale distillation processes may involve more complex and specialized equipment compared to smaller-scale or artisanal distillations.
Feel free to contact Jaybird at NorCal Brewing Solutions for help in designing your advanced distillation system.
What Safety Equipment Might be Used in the Distillation Process?
Basic or advanced - safety is extremely important in distilling. Safety equipment can include pressure relief valves, explosion-proof electrical components, fire suppression systems, and appropriate ventilation to ensure safe and controlled operation. Check your local laws and ordinances for safety equipment requirements based on the products you intend to distill.
Enough about generic distilling... Let's get specific about distilling SPIRITS!
What are the Most Common Still Types?
The most common still types used in preparation of spirits are POT STILLS and COLUMN STILLS. Let's compare the two.
Design: Pot stills have a simple and "traditional" design, consisting of a large pot or boiler where the liquid (known as "wash") is heated, a neck or column that leads to a condenser, and a collection vessel.
Distillation Process: The wash is heated, causing the volatile compounds to vaporize. The vapor rises, passes through the neck and travels to the condenser where it is cooled and condensed back into a liquid. The condensed liquid (distillate) is collected.
Flavor Profile: Pot stills are known for producing spirits with a rich and complex flavor profile. The retained impurities and congeners, such as esters, oils, and other flavor compounds, contribute to the distinctive taste and aroma of the final product. This is a result of their less efficient separation.
Spirits Produced: Pot stills are used to produce rum, whiskies, brandies, and artisanal spirits.
Design: Column stills have a tall vertical column with multiple stages or trays.
Distillation Process: In a column still, the liquid mixture is heated, and different types of vapor begin to form at different temperature levels. As the vapor rises, it encounters multiple trays or plates within the column, where condensation and re-vaporization take place. This allows for repeated separation of volatile components based on their boiling points. Column stills offer efficient separation and higher alcohol concentration.
Flavor Profile: Column stills are known for producing spirits that are lighter and more neutral in flavor compared to pot stills. They tend to remove a higher percentage of impurities and congeners, resulting in a smoother and more refined spirit.
Spirits Produced: Column stills are commonly used in the production of vodka, grain spirits, blended whiskies and neutral grain spirits.
Which Still Design to Choose?
The choice between pot still and column still depends on the desired flavor profile, production capacity, and the type of spirit being produced. Some distilleries use a combination of both still types to create a range or products.
NorCal Brewing Solutions offers pot stills AND column stills, and even modular stills that easily convert back and forth! Here's an example.
Need help deciding between a pot still, a column still, and a convertible still? Contact Jaybird at NorCal Brewing Solutions!
I have a Pot Still. Do I need a Thumper?
There is nothing worse than spirits that are harsh, throat burning, off flavored, or have odors or impurities.
Common distilling wisdom dictates that to avoid the above you should perform multiple distilling runs.
But who’s got time for that?
If you don’t… add a thumper (also known as a thumper keg) – or even a series of thumper kegs – to your pot head distilling system!
What Is a Thumper Keg? (Short Answer)
A thumper keg is a sealed, liquid-holding container that is placed between the still and the condenser in a pot head distillation system.
It has one ethanol vapor entry port and one ethanol vapor exit port.
It essentially performs a secondary distillation during a single distillation run.
A thumper keg enhances alcohol content while simultaneously refining the flavor of the product – whether it be gin, whiskey, rum, or anything else.
How Does a Thumper Keg Work?
Hot ethanol vapor passes from the main still into the thumper through a DOWNCOMER – a tube whose end is submerged in “Thumper Liquid” at the bottom of the thumper.
It is preferrable to have the Thumper Liquid be related to the spirit being distilled.
For example, the Thumper Liquid can be:
· Wash from the current run
· Collection from a prior run
· Store-bought spirit of similar type
· The Thumper Liquid can contain fruit, spices, botanicals, or juice to enhance the flavor (more on this later!)
· "Jaybird" of NorCal Brewing Solutions prefers to use plain, clean water as a "scrubber" to REMOVE impurities instead of adding them.
The hot ethanol vapor bubbles through the Thumper Liquid, cools, and in turn becomes liquid itself, mixing with the Thumper Liquid already in the thumper.
As the vapor condenses in the semi-sealed environment it produces a THUMP – THUMP – THUMP sound, from which the name “Thumper” is derived.
The collected spirit has a high alcohol content and enhances the flavor of the spirit.
At NorCal Brewing Solutions we suggest using using pure, clean water as the thumper , as a thumper is a "scrubber" by design - used to REMOVE impurities instead of adding them!
CAUTION: Due to a thumper’s proximity to the still it will get hot!
For this reason, the thumper keg container should be made from heat-resistant materials (stainless steel, copper, glass, etc.)
NorCal Brewing Solutions manufactures a line of thumpers designed for 1/6 barrel Sanke kegs and an economical line for glass canning jars (Kerr, Mason, and Ball).
Let’s Get Technical!
Okay… but how does this produce a SECONDARY DISTILLATION?
A thumper works by distilling low wines that come from the still.
When distillation first starts, the starting liquid in the thumper keg is cool.
As hot ethanol vapor passes from the still through the thumper the heat waste carried in the low wines heat the thumper up.
NOTE: Typically, no other heat source is used. This allows greater temperature control should the wash temperature get too hot.
Eventually, the low wine gets heated to a point where it vaporizes, a second distillation happens, and this newly distilled vapor passes out of the thumper and into the condenser (or… into ANOTHER thumper keg).
The final spirit exits the condenser and is collected.
In essence, a thumper keg allows a pot head still to gain some of the features provided in the column portion of a column still.
Can a Thumper Keg be Used with a Column Still?
The short answer is “no”. There simply isn’t enough energy left to run the “thump” by the time ethanol vapor leaves a column still.
A Thumper as a Gin Basket!
A thumper keg can be used to add flavor to spirits.
Simply add botanicals, herbs, spices, fruit, juice, or extracts to the Thumper Liquid and the ethanol vapor will extract the flavors from the Thumper Liquid as it passes through the thumper and exits into the condenser.
What Size of Thumper Do I Need?
A thumper should be NO LARGER than approximately 1/3 the size of the still.
So… 1/6 barrel kegs are PERFECT as thumpers when used with a half barrel (15.5 gallon) Sanke keg still.
Half gallon canning jars are PERFECT as thumpers for 1.5-gallon stills.
And don’t forget…
Thumper Kegs can be used in series to double thumper capacity, triple it, and so on.
Two NorCal Brewing Solutions Half Gallon
Canning Jar Thumper Kegs used in Series
First Time Thumper Set-up (Step-by-Step Instructions)
The thumper keg must be cleaned to remove bacteria and other contaminants. An easy way to accomplish this is through a “Vinegar Run”:
NOTE: If using a series of thumpers, perform a Vinegar Run on each thumper individually (don’t assemble them in series).
1) Determine what 20% of the still’s capacity is. (1/6 barrel keg would be 20% of 5.17 gallons = 1.03 gallons). This is the “Vinegar Run Volume”.
2) Assemble the still, thumper, and condenser.
3) Mix half distilled water and half vinegar to make up the Vinegar Run Volume. Pour into the still boiler.
4) Start distillation by heating boiler.
5) Apply heat until distillation vapor temperature reaches 172 degrees Fahrenheit (78 C), hold this temperature for 5 minutes. This should allow the thumper to have collected vinegar.
6) Turn off heat source. Allow all equipment to cool down.
7) Discard all solution from still and from thumper.
8) Thumper is now ready for use.
Using a Thumper Set-up (Step-by-Step Instructions)
1) Assemble the still, thumper(s), and condenser.
2) Add wash to still boiler.
3) Add enough Thumper Liquid to the thumper to cover approximately one inch of the bottom of the downcomer.
4) If using the thumper as a Gin Basket: Add flavorings to the Thumper Liquid.
a. Make sure thumper keg is no more than 2/3 filled with Thumper Liquid and any additives. More than 2/3 full could produce too much back pressure for the thumper to work properly.
5) Heat boiler of the still to approximately 172 degrees Fahrenheit (78 degrees Celsius).
6) As the still heats up, ethanol vapors pass through the still and into the thumper (through the downcomer), where the vapors will turn into liquid and mix with the Thumper Liquid.
7) Eventually the thumper will heat up enough where ethanol vapor will continue out the thumper’s exit port and through the condenser, where it will turn into the final collected spirit.
8) Once the thumping process is complete, turn off the heat source to the boiler.
WARNING: Understand and ALWAYS follow proper still shut-down procedures. Failure to shut down the distilling process correctly can cause back pressure, resulting in equipment damage and even an explosion!
Adding Flavor by Using a Thumper Keg
A thumper can replicate a Gin Basket by adding flavor(s) to distillate!
Simply add fruits, fruit juice, herbs, extracts, flowers, or spices to the Thumper Liquid.
Adding Dried Fruit, Herbs, Flowers, Spices:
Use any combination of dried fruit, herbs, flowers, spices, etc. and place them in a container. Add enough low wines to cover completely. Cover and let sit for 2 weeks or until contents break down and get infused with low wines.
When ready to distill, add this mixture to the Thumper Liquid.
Pros and cons of this method:
PROS: Allows good flavor extraction while keeping the highest possible alcohol content of the collected spirit.
CONS: Time delay / hassle.
Adding Raw Fruit, Fruit Juice:
Use any combination of ripe, mashed fruit and fruit juice and add it to the Thumper Liquid.
Pros and cons of this method:
PROS: Skips the low wines process and the associated time delay.
CONS: Dilutes the alcohol content of the collected spirit. Doesn’t extract as much flavor.
Experiment, and Have Fun!
Thumper kegs add a certain amount of pizazz to a pot head distilling system. Not only do they look cool, the “thump… thump… thump…” sound they make while operating adds an auditory signal that all is going well in the distilling process.
Being able to easily extract flavors from fruit, botanicals, oak, or anything else you dream up adds a whole new dimension to flavor design.
If you don’t have time for multiple distilling runs… If you like the idea of flavor design… If you like a higher proof at collection while getting a refined spirit… then consider adding a thumper keg – or even a series of thumper kegs – to your distilling system.
Remeber Jaybird's motto on ANYTHING regarding brewing and distilling: "Your only limitation is your imagination!"
Questions? Click HERE to “Ask Jaybird” – NorCal Brewing Solutions in-house distilling expert!