The Austrian magazine Genuss has a list of the seven deadly sins to avoid if you want to serve beer on tap. We are talking about keg lagers here, not cask condition ales. Nevertheless:
- Old beer. Once a keg is opened, it should be consumed, preferably on the same day. Not enough turnover to serve beer on tap? Go for good bottled beers instead.
- Right temperature. What matters is the temperature when it is served to the consumer. If the glass is to be carried through a beer garden in high summer, it needs to be kept cold enough.
- Wrong pour. Never let the beer tap into the glass. Never use anything to take off the head.
- Lack of head. Practically all Austrian beers should be served with a proper, good-looking and stable head.
- Rinsing of used glasses. Only freshly washed glasses should be rinsed in the Spülkranz, unless you want to spread Herpes.
- Hygiene. The dispensing system and the bar should be kept clean at all times.
- No cheating. Never fill beer from one glass into another. No pre-tapping to have beer ready. Never.
The translation is a bit halting, but you get the message. Even a humble half liter of lager should be properly cared for.