Publicans sometimes ask us why is it necessary to flush water through the lines before line cleaning? Why not fill the system with line cleaner straight away?
There are several reasons why you flush the beer from the lines before cleaning with a line cleaner. The first is to reduce the cleaning time (even though this answer may sound odd).
Flushing with water helps to push out any accumulated debris which is not stuck to the walls in the lines, such as loose bits of limescale, floating protein, yeast and beer stone. Also, when bacteria starts to grow in a beer line system it is small floating single organisms (Similar to Plankton in the sea) which has not yet stuck to the walls of the line. When you flush with water you remove most of these floating bacteria cells which means that the beer line cleaner can work on the more difficult to remove bacteria which has already stuck to the line walls and started to form biofilm. If you just added beer line cleaner straight to the line its cleaning power would be used up on the floating bacteria meaning your clean would be less effective.
Second is the beer itself. Beer line cleaners are not just for removing bacteria, a good quality one will also remove any sugars, water hardness salts, beer stone salts, proteins as well as clean the lines of tannin stains. Beer naturally contains all of these items, so when the line cleaner pushes the beer from the line some of its cleaning power will be used to “clean” the beer rather than any residues within the pipe, making the cleaning less effective. You can see this if you use a purple beer line cleaner as it will turn green/yellow if it comes into contact with beer showing its cleaning power is being used on the beer and not for cleaning the pipes.
Thirdly there is safety. If the lines are flushed with beer line cleaner to remove the beer within the pipes at the start of cleaning then you run the risk of someone drinking beer which contains line cleaner that has been left around the bar. Line cleaners are extremely dangerous and should never be ingested as they can cause severe damage to your throat and stomach (one gentleman who recently accidentally drank beer line cleaner has had to have this throat removed). Flushing with water means that any beer removed from the lines will only contain water.
If you have any questions about best hygiene practice for your cellar and glass preparation just ask our friends at CellarCraft