Cleaning Homebrew Equipment
Copper & Brass
Copper
The best choice for cleaning copper are cleaners like PBW. For heavily oxidized conditions, acetic acid (white distilled vinegar)is very effective, especially when hot.
The oxides of copper are more easily dissolved by the mildly acidic wort than the copper itself. By cleaning copper tubing with acetic acid once before the first use and rinsing with water immediately after each use, the copper will remain clean with no oxide or wort deposits that could harbor bacteria. Cleaning copper with vinegar should only occasionally be necessary.
You do not need to clean copper shiny-bright after every use. With time, the copper should take on a dull copper color, not black, not green or blue, just dull, like an old penny. This copper oxide is relatively inert to wort and will minimize copper dissolving into the wort, more so than shiny-bright copper.
Cleaning and sanitizing copper with bleach solutions is not recommended. The chlorine and hypochlorites in bleach cause oxidation and blackening of copper and brass. If the oxides come in contact with the mildly acidic wort, the oxides will quickly dissolve, possibly exposing yeast to unhealthy levels of copper during fermentation.
Brass
Some brewers use brass fittings with their wort chillers or other brewing equipment and are concerned about the lead that is present in brass alloys.
A solution of two parts white vinegar to one part hydrogen peroxide (common 3% solution) will remove tarnish and surface lead from brass parts when they are soaked for 5 minutes or less at room temperature.
The brass will turn a buttery yellow color as it is cleaned. If the solution starts to turn green and the brass darkens, then the parts have been soaking too long and the copper in the brass is beginning to dissolve, exposing more lead. The solution has become contaminated and the part should be re-cleaned in a fresh solution.
Filed under: Brewing 101, Microbrewing on July 3rd, 2009
