Bleach (sodium hypochlorite) is powerful stuff. Sodium hypochlorite will disinfect at low concentrations. It just takes longer to do so. One tablespoon per gallon provides approximately 200 ppm chlorine. There are four tablespoons in a 1/4 cup; hence, a quarter cup per gallon provides 800 ppm chlorine, which is extreme overkill. The maximum suggested ppm value per gallon for disinfecting equipment that will come into contact with food is 200 ppm. Three tablespoons per five gallons provides approximatley 600 / 5 = 125 ppm, which will also get the job done as long as the equipment is free of food residue and dirt.
With that said, the threat from chlorine residue is completely overblown. The folklore comes from people who dumped a cup or more of bleach into five gallons of water. At that level, it will be difficult to remove the chlorine smell from any plastic item by rinsing alone. I used bleach as my only sanitizer for over a decade. I never had any off-flavors that could be attributed to using bleach as a sanitizer because I used it properly. I also never experienced the persistent low-level spice problem that I have experienced since switching to Star San as my primary sanitizer. I have noticed that many of the beers that I have judged over that last year suffer from the same problem (I am so sensitive to phenolic spice that I cannot enjoy Hefeweizen or many of the Belgian styles). It finally dawned on me that the abandonment of bleach in favor of Star San may be the source of the problem, which is why I started to study the differences in modes of operation between the two sanitizers.
Bleach is a more effective sanitizer than Star San because its mode of operation is non-selective. Bleach also denatures spores and viruses. If we were to compared Star San and bleach to herbicides, Star San would 2,4-D (the active ingredient in Weed-B-Gon) and bleach would be glyphosate (a.k.a Roundup). Weed-B-Gon is effective against broadleaf plants. The only plants that Roundup does not kill are the GMO crops Monsanto created that are resistant to glyphosate.
From http://www.cdc.gov/hicpac/disinfection_sterilization/6_0disinfection.html
"Chlorine and Chlorine Compounds
Overview. Hypochlorites, the most widely used of the chlorine disinfectants, are available as liquid (e.g., sodium hypochlorite) or solid (e.g., calcium hypochlorite). The most prevalent chlorine products in the United States are aqueous solutions of 5.25%–6.15% sodium hypochlorite (see glossary), usually called household bleach. They have a broad spectrum of antimicrobial activity, do not leave toxic residues, are unaffected by water hardness, are inexpensive and fast acting 328, remove dried or fixed organisms and biofilms from surfaces 465, and have a low incidence of serious toxicity 515-517. Sodium hypochlorite at the concentration used in household bleach (5.25-6.15%) can produce ocular irritation or oropharyngeal, esophageal, and gastric burns 318, 518-522. Other disadvantages of hypochlorites include corrosiveness to metals in high concentrations (>500 ppm), inactivation by organic matter, discoloring or “bleaching” of fabrics, release of toxic chlorine gas when mixed with ammonia or acid (e.g., household cleaning agents) 523-525, and relative stability 327. The microbicidal activity of chlorine is attributed largely to undissociated hypochlorous acid (HOCl). The dissociation of HOCI to the less microbicidal form (hypochlorite ion OCl¯) depends on pH. The disinfecting efficacy of chlorine decreases with an increase in pH that parallels the conversion of undissociated HOCI to OCl¯ 329, 526. A potential hazard is production of the carcinogen bis(chloromethyl) ether when hypochlorite solutions contact formaldehyde 527 and the production of the animal carcinogen trihalomethane when hot water is hyperchlorinated 528. After reviewing environmental fate and ecologic data, EPA has determined the currently registered uses of hypochlorites will not result in unreasonable adverse effects to the environment 529."
