Beer behind the bar

Most of what goes wrong with a beer happens after it leaves the brewery, and nearly all of it's fixable behind the bar.

1. 1Start with a clean, cool, wet glass. A glass out of a hot washer kills the head instantly, and any grease left on it does the same.
2. 2Hold it at about 45° and open the tap fully. A half-opened tap makes foam, not beer.
3. 3Straighten the glass as it fills so the last of the pour lands in the middle and builds the head.
4. 4Finish with two or three fingers of foam. It's not waste, because the head holds the aroma, and a flat beer smells of nothing.

Serving temperature is the other common fault, in the other direction: most beer is poured too cold. Straight from a chiller at 2°C, a good beer tastes of very little, for the same reason freezer vodka does. Lagers want around 4–7°C; ales and stouts are better at 8–12°C.

Lines grow yeast and beer stone, and a dirty line is the usual reason a good keg pours badly. Clean them every two weeks: caustic at two per cent, warm, circulated for fifteen minutes, then flushed until a pH strip says the water is clean. An acid clean every few months shifts the beer stone that caustic leaves behind. Strip and soak the taps while the lines are down.

Every clean throws away a full line of beer, plus what it takes to flush the cleaner out. A bar with long runs from the chiller to the tap wastes more beer every fortnight than one with the kegs under the bar. At the bar I ran it came to $800 to $1,000 a fortnight at sale price, which is the number that makes short lines look cheap.

A keg is beer under pressure. Too much gas and it foams; too little and it pours flat and goes off in the keg. Temperature decides the rest: a warm keg foams whatever the gas is doing, and a cold keg through a warm line foams at the tap. The keg and the line want to be the same temperature.

Wine has its own temperatures and the beer fridge is not one of them. Sparkling wants 6–8 degrees, white 8–12, red 14–18. A fridge set for beer and soft drink runs at 2–4, and a white served straight from it tastes of nothing until it has sat in the glass for ten minutes. I have worked in places that kept the wine in the beer fridge, and the complaint was always the same: they could not taste it.

Beer works in a drink for the same reason soda does - it brings carbonation and dilution - with the difference that it also brings bitterness and malt sweetness of its own, so it can do a liqueur's job as well as a mixer's.

• Michelada - lager, lime, hot sauce and salt. A Bloody Mary's lighter relative and a better hangover drink.
• Shandy or radler - beer and lemonade, roughly half and half.
• Black Velvet - stout and sparkling wine, layered.
• Beer as the top - any sour built long and finished with beer instead of soda. A pale ale over a gin sour works better than it sounds.