Draft beer keg purging: what it is and how to do it

An essential step in draft beer service is purging the keg (known in Portuguese as “sangria”). To make this process easier to understand, we have gathered practical information and a few curiosities about draft beer, the system and how the drink gets to the glass.

What is draft beer and what does it mean to purge a keg?

Draft beer (“chope” in Portuguese) is beer that is not pasteurized before being served. The word comes from schoppe, a German dialect word meaning “half-liter glass.” Around the world, draft beer is known as draft beer or draught beer and generally refers to filtered beer served under pressure.

Over time, kegs — barrels pressurized with CO₂ or nitrogen — replaced the old casks, allowing more stable and safer service.

A draft beer system is made up of gas cylinders, pressure regulator valves, kegs, refrigeration, hoses, a coupler, a tap and fittings. Before serving, you need to purge the line, that is, release the gas and liquid to push the air out of the line until the draft beer reaches the tap.

How to purge a draft beer keg

Whenever you connect a new keg, you need to purge the line and adjust the flow. Below, we explain the step by step.

1. Check that everything is connected correctly

First of all, check:

• The keg is seated firmly and the coupler lever is locked down.
• The gas (CO₂ or blend) is open and at the right pressure.
• You have a pitcher or bucket on hand to collect the initial draft beer.

This check should be done every time you change a keg.

2. Open the compensator completely

Before opening the tap, adjust the compensator. On Italian taps, which are very common, the control is a small lever (pin). When the pin is up, the flow is usually closed; down, it is open.

So, set the pin all the way down. If no liquid comes out, try the opposite, as how it works can vary by model.

3. Purge the line

Now, let's get to the process:

• Place the container under the tap and pull the lever to release the liquid.
• Keep the lever open until the liquid starts coming out steadily (at first it will be foam and sputtering).
• Start closing the compensator little by little to adjust the flow.
• As you set the pin upward, the flow decreases. The draft beer starts coming out in the color of its style: black (Stout), golden (Pilsner), amber (IPA), and so on.
• When you reach a stable, appropriate flow, the purge is complete.

Tip: The ideal flow varies by draft beer style and carbonation level. Watch the liquid coming out and adjust as needed.

Now the system is ready to serve quality draft beer!

But what about waste?

Unfortunately, waste is part of traditional draft beer service. Estimates indicate that 25% to 30% of a keg's contents can be lost — which means that, in the worst case, a quarter of your investment literally goes down the drain.

A good part of this loss happens precisely during purging and because of problems with the head, pressure or temperature. That is why it is essential to monitor these three factors.

How to avoid waste: myTapp technology

Since 2015, myTapp has brought the self-pour draft beer system to Brazil. With it, waste drops to about 5%.

This result is possible thanks to precise control of every milliliter that leaves the keg. The customer pours and pays exactly for what they draw. On the other side, the bar manager accesses a complete dashboard with:

• Draft beer levels per keg
• Days and times of highest consumption
• Cleaning alerts
• Consumption information per customer

All of this can be tracked on a phone or computer, in real time.

In addition, the myTapp system has a feature that blocks gas from entering the line during a keg change. This detail further reduces losses of draft beer and gas, improving your business's profitability.

Want to know more?

If you want to offer higher-quality draft beer with less waste, talk to myTapp. Our self-pour technology can transform the operation of your bar, hotel or event.

I want it!