|In the world of sanitizers, you will find a wide range of sanitizing agents available to home brewers. One of the favorites is a halogen sanitizer/germicide called Iodophor. And most home brewers have used this product at one time or another. But you will find there is an amazing amount of confusion and misinformation about this product. No one seems to agree on the proper concentration, the required contact time, or even what "no-rinse" means.
Iodophor is a federally approved contact sanitizer that is used widely by resturant, food production, and dairy industry. You will find it most commonly available to home brewers in 4 oz. and 1 liter bottles. What Iodophor actually is and how it is used properly can be a mystery, most of us suffer from misinformation of this product.
According to "National Chemicals Inc.", manufactures of a popular brand of iodophor known as "B-T-F" Iodophor, it is effective at a concentration of 12.5 ppm of titratable iodine, and at that strength, is an effective sanitizer with a contact time of as little as 60 seconds. However I recomend 5 minutes if you can. This is equal to 1/2 ounce or approximatly 2 capfuls added to 5 gallons of cold water. Yes cold water makes more effective then hot water.
Iodophor’s orgins come from its usage in the dairy industry. It became a popular dairy germicide which then became widely used in the food processing industry. Of course taverns and breweries were included in that industry. The original iodophor sanitizers were formulated with acids, (phosphoric and others),. This was done to help in the release of the iodine ion into solution. These older iodophor formulations needed the lowered pH to work properly. However, the "newer" formulations of iodophor, (such as B-T-F Iodophor), do not require the low pH to work properly.
Once Iodophor has been diluted to a working solution, that there are a number of things that work to degrade the products' efficacy. Chlorine and protein load, as well as both sunlight and exposure to the atmosphere all play major roles in the degredration. Iodophor is very stable in it's undiluted form. As for the "shelf life" of B-T-F Iodophor, Dr. Landman, General Manager of "National Chemicals Inc." of Winona, MN. and is a Ph.D. in Medical Microbiology, relates a story about one of their distributors who had found a case of the product that had been forgotten for 5 years and returned it to the manufacturer. NCI tested the 5-year-old product and found that it still met standards. This was, of course, undiluted iodophor that had been well packaged and protected from exposure to light, air etc. In either case, it is far more stable than chlorine, which begins to degrade immediately upon being manufactured. The color of the iodophor solution is a rough guide to it's effectiveness as a sanitizer. If the solution still has its amber color, it is most likely still active. It is recommended that a fresh solution should be mixed when the color fades or after 12 hours.
Please remember, Iodophor is not a cleaning agent. In fact, introducing dirty items to the Iodophor solution will degrade it’s sanitizing properties rapidly. Items to be sanitized must be thoroughly cleaned before hand. Chlorine bleach is no more effective at sanitizing dirty items than is iodine, however makes an excellent cleaner. It is recomended to rinse well and allow to air dry after using bleach. By then coming back and useing Iodophor, you have decreased any chances of either cross-contamination as well as bacteria mutation. There is much discussion among home brewers about the dangers of scratches in the walls of plastic fermenters, but that the real problem is in inadequate cleaning. Organic material can imbed in scratches in any material. If that material is allowed to remain, no sanitizer can be expected to prevent bacteria from forming.
"NO RINSE" is a phrase that is frequently used in conjunction with iodophor. Manufacturers of iodophor claim that, when used in a solution of 12.5 ppm., there is no need to rinse the solution from items. They say that the item should be merely air dried. But actually, air-drying isn't really necessary. I don’t want to chance becomeing contaminated at some time after drying. Some people feel as though the odor of iodine from a freshly sanitized carboy is far too intense to believe that there would be no deleterious effect upon contact with their beer. In all my years of home brewing, I’ve never had any adverse effects useing Iodophor in the above mention methods.