Dear Mr. Wizard,

In the question about root-beer flavors in kegs (“The Root of the Problem,” November 2002), the question- writer mentioned that bleach is a no-no. Of course, I read this not more than two hours after putting a bleach solution through a couple of Cornelius kegs. I have also read that you should periodically soak your transfer hoses overnight. So my question is, when is it appropriate to use bleach and when is it not?

Glen A. Hickox
Colorado Springs, Colorado

Mr. Wizard answers:

The author of the question about root-beer tainted beer did acknowledge in his question that bleach is a “no-no.” I focused on the root-beer flavor taint and should have commented on that assertion because bleach can have its place in the brewery. Household bleach, or sodium hypochlorite, has a bad reputation primarily because of what it can do to beer flavor. When phenols — which are present in malt, wort and beer — react with bleach a potently aromatic compound called chlorophenol is formed. Chlorophenols are described as medicinal and remind me of the aroma of the throat spray Chloraseptic.

The strong medicinal aroma of chlorophenol is considered a defect in all beer. The easiest way to avoid this particular problem is to keep bleach out of your wort and beer; this means that you must thoroughly rinse equipment sanitized or cleaned in bleach, until the rinse water has no bleachy aroma or taste. Of course, if your local water is heavily chlorinated it already smells like bleach, and this water can cause chlorophenol problems without using a bleach sanitizer — but this is another issue. I prefer using sanitizers that do not require rinsing and so I use compounds other than bleach for sanitizing. My favorite is peroxyacetic acid (or PAA).

Bleach is a strong oxidizing chemical and it works extremely well as a sanitizer and as a cleaner. In fact, many industrial caustic cleaners (usually sodium hydroxide) are enhanced by the addition of bleach. These so-called chlorinated caustics are much more effective in the removal of protein films than regular caustic and are used by many brewers in the brew kettle where cleaning is most difficult.

The major downside to chlorinated cleaners is that chlorine can corrode stainless steel when the pH of the chlorinated solution is low (or acidic). Since caustic cleaners are alkaline and have a high pH, stainless steel can be safely cleaned with these chlorinated caustics.

Household bleach is also alkaline and has a pH around 12. This means that bleach can be used on stainless steel. However, when multiple cleaners are used for cleaning, it is possible for a chlorinated liquid residue to become acidic and thus corrosive. This can happen, for example, when a vessel is cleaned with a chlorinated cleaner followed by an acid-based cleaner or sanitizer.

This whole topic is pretty controversial among cleaning experts and stainless steel experts. Some argue that as long as the pH of chlorinated cleaners is kept alkaline then chlorinated cleaners are OK on stainless steel. Others argue that chlorinated cleaners should be avoided at all costs because of this multiple cleaner scenario. My advice is to avoid using chlorinated cleaners unless you clearly understand how and when they can cause corrosion.

If you want to use bleach as a cleaner, you can do it without problem. I recommend the cheap bleaches that only contain sodium hypochlorite. High-end bleaches, like lemon-scented Clorox, usually have scents to make them smell less like bleach and these should be avoided. Bleach works great for soaking hoses and for cleaning glass. You can also use it for special cleaning projects on stainless steel. For instance, I periodically — perhaps every one in ten cleanings — add plain bleach to caustic to remove a protein film that slowly builds over time in our whirlpool. This film accumulates despite the fact that we clean our whirlpool with caustic after every use. However, because of its potential corrosiveness, bleach should not be used as an everyday stainless cleaner. Finally, bleach is a great sanitizer if you don’t mind running the risk of the dreaded chlorophenol nose!

The concentration required for good sanitizing action is really pretty low. The state of Kansas, for example, requires restaurants to use 100 ppm for dishwashers with a cool-water sanitize step (that’s roughly two teaspoons of bleach per gallon or 3.8 liters). The University of Montana state-extension Website recommends 50 ppm for household sanitation of dishes and 100 ppm for sanitizing counter-tops and appliances. Cleaning is another issue — concentrations from 6–12 ounces per gallon (47–94 mL per liter) of water are more common. When I add bleach to caustic, I add about 12 ounces (355 mL) of bleach to two gallons (7.6 L) of a 2% caustic solution. That’s one potent cleaner!

For more information on cleaning and sanitizing, see Steve Bader’s article, “Beer Minus Bacteria,” in the January-February 2003 issue.

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