Dear Mr. Wizard,
In the question about root-beer flavors in kegs (“The Root of the Prob-lem,” 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!
Dear Mr. Wizard,
I use iodophor to sterilize and mix it according to the directions on the bottle. Do you have to rinse after you sterilize with it? I never have and I’ve never had any off-flavors, but I wonder if it is slowly eating away my insides.
Mr. Wizard replies:
Iodophor is a very effective sanitizer and, unlike bleach, can safely be used as a no-rinse sanitizer without adversely affecting the flavor of your beer. The recommended concentration of iodophor is 25 parts per million. Most iodophors are diluted so that the typical use rate is somewhere around 0.1 ounce per gallon (7.8 mL per liter). They are always labeled with instructions giving suggested usage rates. If you use it at this concentration and allow your equipment to properly drain, you will be in good shape. Iodophor does have a flavor and, when used at higher-than-recommended strengths, it can impart an iodine flavor to beer — especially if it is not drained from the equipment surface.
Excessive iodine intake (extended consumption of about 0.75 milligrams per day) can cause iodine goiter, a condition characterized by enlargement of the thyroid gland. One ounce of a 25 ppm iodophor solution contains 0.75 milligrams of iodine. To leave that much sanitizer on your equipment would correspond to very careless technique. In addition, your beer would taste objectionable and the off-flavor would be a good warning sign to pay attention to your sanitation procedures. I suppose the flip side is that if you had 1/10th of an ounce (which is still a pretty fair volume) of residual on beer bottles and drank 10 beers per day you could have the same effect.
For more information on cleaning and sanitizing, see Steve Bader’s article, “Beer Minus Bacteria,” in this issue.
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