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
For the beer, a serving size that is appropriate should:
For the tasting situation we have to consider:
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.