In the United Kingdom, it is illegal to sell a pint of beer with less than 568mL of liquid. This corresponds to 20 imperial ounces, which is about 19.2 US ounces. Similarly, "half pints" must contain no less than 284mL, and "third pints" no less than 189.3mL. To enforce this law, pubs in the UK serve beers in marked glasses, with clear lines that show at what point a pint has been reached. There are inspections. There are regulators. There are customers who politely ask for a "top up" when this line isn't met. And as a result, this line is met. Customers who expect a pint receive an imperial pint at a minimum.
The United States Treasury, through powers granted by Article 1, Section 8 of the U.S. Constitution, defined, in 1832, a gallon as 231 cubic inches. As part of the US Code obligations, every state has, on behalf of the Secretary of Commerce, a complete set of "weights and measures," that include a gallon and divisions thereof: half gallons, quarts, pints, half pints, and gills. Thus, a pint, according to US law, is 28.875 cubic inches, or precisely 16 US ounces (473mL).
And yet, when you buy a pint of beer in this country, there is no guarantee that you will get those 16 ounces. In fact the opposite is true: thanks to under-pouring and misleading glassware, you are likely to get much less.
The "standard American shaker pint" glass, the kind you probably think of as a pint glass, holds exactly 16 ounces. Exactly. No room for spillage, and in fact, pour a tall boy of beer into one and you'll note a "reverse miniscus" of liquid, as surface tension keeps the liquid from pouring over the side. But when was the last time you were served, at a bar, a nearly-overflowing glass of beer? When standard shaker pints are used, you're much more likely to receive around fourteen ounces of beer, accounting for head and empty space to prevent (or caused by) spillage.
And yet the problem compounds further: bantam-weight shaker pints, which have thicker walls, a much thicker floor, and are commonly used with a stainless steel Boston shaker to shake cocktails, hold a maximum of 14 ounces of liquid. Again, this is exact. Any more than 14 ounces, and that surface tension will break, sending liquid spilling over the side. And today, many bars have switched from the already questionable American shaker pint to that bantam-weight shaker pint, meaning that once you account for head and spillage, you're likely receiving only around 12 ounces when you ask for a pint. A 25% discount in liquid that surely is not represented in the price.
As it happens, the State of Texas actually does have a law that deals with this, but the Department of Agriculture, responsible for its enforcement, apparently focuses entirely on its application to fuel pumps. The relevant section that should be applied to bars and restaurants that under-serve is Section 13.035(b)(2): "A person violates this chapter if the person represents the price or the quantity of a commodity, item, or service sold or offered or exposed for sale in a manner intended or tending to mislead or deceive an actual or prospective customer."
I think it's time for this state, and any other state that has similar laws, to begin enforcement of this. The law provides for a fine for every infraction, and I think it's time that those fines be levied. States that don't have similar laws ought to legislate thusly. The customer is being cheated, lied to, and this is a disgrace. I'd like to see marked pint glasses that clearly and correctly show where liquid reaches 16 ounces. I'd like to see the demise of both the American shaker pint and its even more devious bantam-weight cousin as serving vessels. And I'd like to see establishments stop cheating customers, be it through good conscience or through proper application of consumer protection laws.
But it also requires action from the customers. Demand a full pint. Demand top-ups to get to 16 ounces when American shaker pints are used, and stop patronizing establishments that cheat you out of volume. Order cans or 12-ounce bottles and ask for a pint glass, to demonstrate the embarrassing pour that occurs when bantam-weight shaker pints are used. This cheating needs to end, but it'll take a lot of work for us to get our full pour.