How Does a Thump Keg Work?

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A thump keg is one of the vital pieces of equipment in a moonshine still. It is a small container, usually made of steel, copper, or wooden material, placed between the still and the condenser. So, how does a thump keg work, and how does it perfect the moonshine-making process?

How Does a Thump Keg Work? 

A thump keg works by adding a second distillation process to the moonshine, using the vapor’s waste heat to distill the low wines a second time. This process is also known as “thumping,” It increases the alcohol content in the moonshine.

An image of how does a thump keg work

In other words, it is a secondary distillation and condensing chamber that allows for the alcohol molecules to be separated from the water molecules through the process of heating and cooling. In this manner, the thump keg helps to produce a higher-quality moonshine.

While most thump kegs are placed between the still and the condenser, some moonshiners might also use a separate condensing chamber. The purpose of the thump keg is to provide a means for the low wines to distill further to produce a higher alcohol content. You can even add mash into a thumper keg to speed up the distillation process.

The History of the Thump Keg

The thump keg is a type of wooden cask or barrel that was used in the 18th and 19th centuries to store and serve beer in taverns. Thump kegs were typically made from oak and had a capacity of between two and five gallons of beer. The name “thump keg” comes from the sound made when the tap was pounded on the top of the keg.

The European attitude towards alcohol was not particularly positive during the 18th and 19th centuries, especially in Britain. However, brewing beer at home was commonplace, which led to the popularity of the thump keg. Homebrewed beer was often stored in wooden barrels or casks, and when it was time to serve it, the keg would be brought to the tavern and tapped.

Today, the thump keg is making a comeback as a popular way to increase the alcohol content and flavor of craft beer. Brewers are using larger kegs as vessels for aging and storing their beers, giving them more time to develop the complex flavors that are beginning to appeal to many discerning craft beer drinkers.

How It Works Exactly

A typical distilling setup has three parts, the thumper keg, a pot still, and a coil condenser. The thumper keg sits between the still and the condenser, where Low wine vapor that is usually too strong run through the still and is directed to the thumper. The Low wine is cooled and condensed in the thumper, which allows for a greater alcohol concentration.

The vapor then goes through the coil condenser and into the pot still, where it is vaporized. This vaporization increases the alcohol content even more before going to an outlet. The bubbles in the beer pressurize the keg as they escape through the pressure relief valve, causing a rhythmic “thumping” sound.

An image of a silver thump keg

The condensed vapor is then passed through the coil condenser and finally collected in a receiver. This alcohol-rich vapor is then redistilled to increase its proof even further. The following is the summary of the process:

  • Low wine vapor is directed to the thumper keg
  • The vapor is then passed through the coil condenser, where it increases in alcohol content before being redistilled and collected.
  • The condensed vapor is received in a receiver.
  • The final product is an alcohol-rich vapor that is ready to be enjoyed.

Infusing Flavors Using a Thumper Keg

Besides its use for distilling and increasing alcohol content, a thumper keg can also be used to infuse extra flavors into beer or other alcoholic beverages. This way, brewers can experiment with different flavors and achieve the perfect balance of taste and alcohol content.

The following are options for infusing flavors using a thumper keg:

Add Fruit-Infused Spirits to Your Thumper Keg

Fruit-infused spirits are a great way to add flavor to your thumper keg. You can infuse any type of fruit into the spirit, such as oranges, lemons, limes, or berries. Simply add the fruit of your choice to the thumper keg and let it sit for two weeks before adding the spirit.

When you want to distill, simply add the fruit-infused spirit to the thumper keg and follow the usual distilling process. The final product will be an alcoholic beverage with a subtle fruit flavor.

Add Herbs and Spices to Your Thumper Keg

If you want to create a more complex or unusual flavor, you can infuse herbs and spices into the thumper keg. This is a great way to experiment with different flavor combinations and find the perfect recipe for your craft beer.

Some common herbs and spices to infuse into the thumper keg include cardamom, anise, cloves, and cinnamon. You can also experiment with other herbs and spices to create your own unique flavor.

Add Oils or Juice Into Your Thumper

Adding oil and juice directly to a thumper keg can create a more intense flavor. This is a popular way to add unique flavors to gins, which are often infused with fruit, herbs, and spices.

This time you are adding them in the liquid form, e.g., orange juice, which is much easier than if you were doing it as a puree or infusion into the thumper keg. You can also add essential oils to the thumper keg for a more concentrated flavor.

This method is quick as you don’t have to wait for the flavors to infuse into the spirit. However, it can be tricky to get the perfect balance of flavor and alcohol content. Therefore, it may be best to experiment with small batches until you find a recipe that you like.

An image of a thump keg near a brick wall

The Benefits of Using a Thumper Keg

Thumper keg comes with many benefits for those who enjoy alcohol. You don’t want to miss out on these benefits, which include:

  • You can save money by brewing your own alcohol at home and avoiding the high cost of buying alcohol from the store.
  • You can control the flavor and proof of your alcohol by infusing it with fruit, herbs, and spices.
  • You can experiment with different recipes to find the perfect balance of taste and alcohol content. This also allows you to create unique and unusual flavors, which can be a great way to entertain friends and family.
  • The alcohol with low proof can be easily increased by re-distilling it in the thumper keg. This will help you produce a high-quality drink that is sure to impress.
  • The materials required for the process are easy to find and affordable. Therefore, you can enjoy all the benefits of distilling alcohol without spending a lot of money.
  • The process does not require any special skill or training. Therefore, anyone can learn to use a thumper keg at home and create high-quality alcohol with unique flavors.

Related Questions

What Liquid Do You Use to Clean a Thumper Keg?

You can use mild soap, vinegar, and warm water to clean your thumper keg. Avoid using harsh chemicals, as these can damage the inside of the thumper keg and cause a bad flavor.

How Long Does It Take for Infused Spirits to Ferment?

The amount of time needed for infused spirits to ferment will depend on the type and strength of your ingredients. Most liquid infusions require two weeks to ferment.


A keg thumper is one of the important components of any home distilling setup. Therefore, it is important to know how your thumper keg works, what size to buy, and how you can use it to create unique flavors and infusions.