There are two advertisements for lager running on British TV at the moment. The first, for American brand Budweiser, suggests that the key to good lager is fast shipment from brewery to bottle to drinker. It says fresh lager tastes better. The second, for Dutch beer Grolsch, makes exactly the opposite claim. It stresses the importance of a long conditioning period to improve flavour before the beer is bottled. Which will produce a better beer and why?