How can putting water in beer be dangerous, or indeed impossible?
I ask merely out of interest.
(idle insomniac enjoys listening to Sigur Rós at stupid hours, Thu 16 Apr 2009, 12:50, 2 replies)

The frothy stuff
is made by carbon dioxide (or nitrogen) bubbles. To make these stay sequestered within the liquid the liquid is kept at a high pressure. Not sure of the value of this pressure, but you try blowing hard enough into a bottle of coke / beer that the bubbles stop. Can't be done.

To water down beer you'd have to compete against this pressure with your own water pressure, depressurise it/mix it/pressurise it or what have you. It's not just a case of running a length of hose from a tap to a hole drilled in the top of the barrel or having a Y-Splice in the delivery tube going off to the mains water supply.

The only way I can think of them doing it on the cheap would be to have the tap alternate between beer and water feeds- but that'd need a lot of work to ensure no-one noticed.

If they really wanted to do it they could, but it'd need someone willing to put a pretty huge amount of time and money into doing it for the payoff of... crap beer. You'd take a good long while to make a profit of even the most basic versions of such a kit unless you were doing a really noticeable amount of watering down.
( uberdeity Wondered why Owen Lars knew of the term "hell" on, Thu 16 Apr 2009, 13:37, closed)

*points up*
a lot of what he said.

It can be done (by a suitably experienced engineer) - by modifying the gassing system to drive water into the barrel as you take beer out, or by inline dilution, but it would cost more than you'd ever save in beer.

And it's dangerous because you are fucking with a pressurised system. And with the barrel connection, you're fucking with a pressurised system containing a spike highly capable of being blown out upwards at the kind of velocites that would necessitate steam-cleaning the walls if you got any part of your body in the way.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 16 Apr 2009, 14:25, closed)