Can I use a 5 litre heineken keg to dispense homebrew?
There are 5 liter keg systems available at your local homebrew store. They have replacement bungs and CO2 injectors available so while technically you can reuse them it’s really a PITA when you take into consideration how easily damaged they are, how difficult to clean, and what a low value for the money they are. It’s much more cost effective, fun, and pain free to just use your corny. If you’re concerned about portability, there are also 3 gallon cornies and there are small CO2 cylinders dispensing systems. I sometimes take my homebrew in 2 L soda bottles. You can take the cap of a 2L bottle, drill a hole in it, and add an air valve. With an air chuck on a line to your CO2 tank you can even carbonate right in the bottle.
