I saw a comment asking this question here, and became curious. In the context of a tasting panel or competition, what is the appropriate serving size?
There are two angles to consider
- what is best for the beer
- what is best for the tasting scenario
For the beer, a serving size that is appropriate should:
- provide sufficient beer to not warm up excessively in the cup or glass in the minute or two tasting is underway. This means serving sizes should be at least 60ml/2 oz. (If the beer is served too cold, leave it in the bottle to warm, so that all samples are poured together and tasted at the same temperature.)
For the tasting situation we have to consider:
There may be a limited amount of an evaluation beer to share between the number of judges so serving sizes should be restrained.
Furthermore, some additional beer should be left over in case a re-evaluation is necessary. This is particularly important with styles where volatiles are a key contributor, since they dissipate quickly, plus the olfactory sense quickly becomes tired, requiring a pause and then a fresh sample.
Taking these two into account gives a typical serving size in the order of 3-4oz/75-100ml.
Note that the glass can be larger - particularly a long tall glass is good for capturing the aromatics of a smaller sample.
You want to have enough beer so that a person would be able to see the head profile along with getting a good look at the color/clarity of the beer. Along with being able to take 2 - 3 sips of the beer.
A tasting would be a larger pour as this would be more of a friendly gathering and you want the people to enjoy the beer, I would aim for 4 - 6 oz. It is also not too much if they don't like it. For a tasting, you don't really care if people are getting drunk.
For a competition since you are not aiming to really "drink" the beer, I would say that it would probably be 2 - 3 oz. Judges are going to aim to not get drunk on the beer, so the smaller pour helps with that.