When I think about glass sizes my memory is drawn to my experiences while travelling overseas particularly a bar I visited in Amsterdam where, from my limited understanding, it appeared that all the beers and there were a considerable number of beers available were the same price. A large blackboard displaying the beer menu had one price, in guilders in those days, highlighted in the title.
After receiving an Amstel lager in a rather classy jug-size glass, I sat drinking, soaking in the atmosphere and looking forward to my next selection which was going to be something new. Obviously the alcohol was having an effect and I was feeling more relaxed and my worries were melting away - or was this the effect of breathing in the haze in the room for a sustained length of time? So up to the bar I went with my jug in my hand and confidently ordered something from a little further down the list, my super tanker was taken from me and replaced with a small dinghy sized glass of my selected beverage.
Of course this approach to standardization can be done in a place where every beer comes with its own labelled glass in a size appropriate to the alcohol content of the beer, but the advantages can clearly be seen. The public are able to go to a bar and know that they will be able to have two drinks before becoming incapable of driving and they may decide that six drinks is their limit. They know how much those six drinks will cost them, no matter what beers they choose to drink and whether they enter into a round of drinks with friends the cost of each round is the same.
I'm not suggesting that we implement a system in New Zealand that involves every pub and bar stocking a multitude of glass sizes for every different beer or ABV level, although considering that 99% of bars only serve 4% - 5% ABV beers this wouldn't be a huge burden. But, we do need to have a way of standardizing alcohol servings so that people can work out how much alcohol they are consuming.
But wait, we already have this with Standard Drinks. One Standard Drink equals 10 grams of pure alcohol. All alcohol containers now have a Standard Drinks content on the label. Unfortunately there doesn't seem to be any similar guideline or labelling requirement for beer served from a tap. We're all aware of the great variety of glass types that beer is now served in at bars from a 440ml Boston glass, often referred to as a pint, to a 560ml pint glass. Lagers should be poured into a 330 ml stemmed glass, Duvel at 8% ABV is served in the famous 300ml tulip shaped glass or Chimay Blue at 9% ABV is served in the 400ml Chimay chalice whereas you are likely to get served a Franziskaner Weissbier at 5%ABV in a 500ml Weizen glass.
Often bars that specialize in beer will have a menu or a blackboard showing the beers currently available on tap, they may include a description of the beer and the ABV percentage. This leaves the drinker, possibly after already consuming a number entries on the menu, with the difficult mathematical task of calculating how much alcohol they have consumed. Normally, of course they don't and leave it up to their finely honed senses to trigger the visit to the kebab shop.
Most bars serve their beers in one or two sizes glasses, sometimes people may request a half of a particular beer, what they actually end up receiving is anyone's guess. Australians use the terms schooner, middy and pot to describe 15oz and 10oz volumes although the meaning of these descriptions varies from state to state. But having standard glass sizes or terms doesn't solve the drinker's problem of determining how much alcohol has been consumed.
Why not apply the same rules requiring the labelling of alcohol containers with Standard Drinks quantity to beer available on tap? Bars wouldn't need to change the glasses they currently use to serve the beer, they would simply need to post a menu of available tap beers and the Standard Drink quantities for these beers based on the glass sizes they normally serve the beers in. The drinkers job is then one of adding up the Standard Drinks to work out the volume of pure alcohol consumed, okay so maybe this is too tricky for some of us but at least it's a start. It doesn't solve the problem of spending too much in a night or people not buying their round, that's a different issue.