Freshly tapped beer is pure enjoyment for every beer lover, especially in a bar, beer garden, restaurant or pub. It should have the right temperature, the right amount of fizz, be aromatic – and have the perfect head. Properties bottled beer simply doesn’t have.
Therefore, it is very important that restaurateurs provide the best possible quality beer. But it is not unusual that beer foams too much or too little when being tapped. This is not only bad for the customers, but also for the turnover of the bar because beer often gets left in the bottom of the keg.
What can I do to avoid problems when pouring beer? We will explain.
Why does beer foam when being poured?
Firstly, we need to ask ourselves which factors influence the production of foam when pouring beer:
Natural carbonation occurs during fermentation. It provides the fresh taste and gives each beer its individual touch.
The CO2 pressure in the draught system
For the beer to reach the tap, pressure from a gas dispenser is needed. An additional supply of CO2 also helps to retain the natural carbonation of the beer.
A further important factor is the temperature. Beer kegs should ideally be kept in a cool room so that the beer is pleasantly tempered. The optimum temperature is 5.8 degrees Celsius. But that’s not the only reason! The temperature has a big influence on the CO2 pressure of the draught system. Pressure problems can therefore occur when the temperature varies. This is a big issue, especially at festivals, outdoor events or bars that cannot guarantee stable temperatures.
A perfectly poured beer needs to be tapped properly. The correct technique is very important to ensure that the head is not too big or too small.
Problems when tapping beer? This is what I can do
We now know which factors have a decisive influence on the quality of a freshly poured beer. What do I have to do to tap beer correctly?
The beer foams too much
It is important to use the correct technique when tapping beer. Hold the beer glass at a slant under the tap to keep the head formation at a minimum to begin with. At the end, hold the glass straight to ensure a proper head is formed. If the beer is too foamy despite following this technique, the reason could be the system pressure. Check if the draught system is installed properly. If the beer gets warmer, for example, the CO2 pressure needs to be increased. Too little pressure on a warm day can lead to released carbon dioxide, which leads to foaming. But be careful: too much pressure can also lead to over-foaming if the beer shoots out of the tap.
Too little foam
If the beer does not have enough foam, then the opposite should be done: when filling the glass, do not hold it at a slant for too long. At the end you must hold the glass straight to increase the foam and achieve the desired head. If that doesn’t help, the system pressure could be the problem. Check the draught system and set the optimum CO2 pressure. If the temperature is low, the CO2 pressure must also be low. Too little pressure can lead to beer flowing very slowly out of the tap and therefore forming very little foam.
Beer saturation pressure
The CO2 pressure is directly related to the temperature of the beer, also known as saturation pressure. Temperature changes are therefore the most common reason for the wrong CO2 pressure. The correct values can be seen in the table:
If you are still not satisfied with your draught beer, the following reasons could play a part:
The beer glass
Make sure you are using clean and cooled glasses. The temperature of the glass should be as similar as possible to the temperature of the beer.
Clean the glass properly
A beer glass should be rinsed with clean water before it is filled, definitely not with detergent. You can use a detergent, but the glass must be rinsed afterwards. Use a dry glass.
Wrong tap use
If the tap is not fully opened when pouring, the beer is squeezed out of the tap leading to a lot of foam.
The draught system is installed wrongly or is defect
If the draught system is wrongly installed or is defect, various problems can occur when pouring beer. If you think the system has a problem, contact a specialist to check your system properly.