While it may not be that exciting a topic, it is really important for the condition of the beer being sold. I wonder how many publicans actually observed the practices suggested here?
"If beer is kept in the cellar of the house, as it usually is, owing to the necessity of keeping it in a level temperature of about 55°, it is drawn to the bar by means of a suction pipe and flexible tubing, from the tap to what is called the Union, where, generally, all the flexible pipes meet in the ceiling, and are joined to a similar number of lead pipes, or sometimes rubber tubing, to the engine in the bar.Obviously, the lead piping wouldn't be allowed today. It's particularly dangerous when the liquid flowing through it is acidic, as beer is. It'll dissolve some of the lead a treat.
The scantling in the cellar should be, as far as possible, perpendicularly below the engine, to allow of as short a run of piping as possible, both from motives of economy, and because the beer that stands in the pipe is by no means palatable, and should not be given to customers, but drawn off, and replaced, by means of a fllter, into the barrel. The piping quickly gets foul, and it should be cleaned twice a week, preferably by the use of a patent preparation called the Invicta Pipe-cleaning Medium, or some other of a similar kind. Failing that, it is possible to clean the pipes by drawing strong soda-water through them and through the pump: afterwards clear cold water, finally rinsing with beer.
There are various kinds of beer-piping — some is of lead, some rubber-jointed composition, some rubber, some wired rubber, and the best, and most expensive, porcelain lined. That most commonly in favour just now is armoured rubber. The jointed-rubber piping is not now popular, as joints sometimes burst, and this may involve serious loss of the contents of the barrel."
"The Art and Practice of Innkeeping" by Alexander Francis Part, published by Heinemann London, 1922, pages 200 - 201.
I had to look up what scantling means. At fears I thought it might be an OCR error. "A timber beam of small cross section" is evidently what it is. So, in this sense, bits of wood to hold the cask in position. Stillage, I gues is what you'd call it today.
Fair enough not serving beer that had been sitting in the pipes to customers. But tipping it back into the cask was only diluting, not solving, the problem. And it sounds very much the same practice - and using the same equipment - as putting slops back into a cask. Which I'm sure was pretty common. Though finding any hard evidence is well nigh impossible.
Twice a week sound more than reasonable for line cleaning. How often do publicans clean their lines nowadays?