Nydalen Bryggeri & Spiseri is home to one of Amundsen Bryggeri’s two production sites and has 24 different types of beer on tap in addition to around 160 types of bottled beer. Their maximum capacity per year is approximately 150,000 litres. For this, roughly 1,250 litres of CO₂ are required for carbonating the beer (carbonation is the name of the process in which carbon dioxide (CO₂), is added to a liquid). The right amount of carbon dioxide in beer is also an important factor for the taste experience.
"CO₂ is already produced during fermentation, but as part of the CO₂ is released in a controlled manner from the containers during fermentation, we often have to add extra. Carbon dioxide enriches the taste experience and produces a more refreshing beer, but the right balance is important. Some beers can be fizzy like champagne, while in others, the carbon dioxide is scarcely perceptible. The amount of carbon dioxide in beer varies greatly depending on the type of beer. The light, refreshing beer types require more carbon dioxide than the heavier and stronger kinds. For example, a light lager contains much more carbon dioxide than a strong stout," explains Jæger.
The addition of carbon dioxide to beer also depends on the temperature of the beer and the CO₂ pressure. The optimum temperature for carbonation is between 0 and 5°C. CO₂ is absorbed more quickly at low temperatures, which means that a higher CO₂ pressure is needed at higher temperatures. Different types of beer foam differently, and many things affect this. The foam on beer consists mainly of proteins originating from the malt that the beer is brewed from. The foam is created by large protein molecules, and when the beer is affected by pumps and filters, for example, these molecules are broken down, making it foam. Therefore, the more the beer is processed, the less foam there is. "A good glass of beer should have a good head, but the whole glass should not be filled with foam. There are many reasons for beer to foam too much when drawn from the barrel via a tap. Most often, foaming is due to too high a CO₂ pressure in the barrel or the wrong tap system. Fat also affects the foam quality," says Jæger.