Great Lakes Brewing News Archive

Homebrew Talk

Originally Published: 10/97

By: Dave Bone

Beer and unfermented wort are attractive food sources to a wide range of microorganisms. Laden with sugar and rich in nutrients, they can be quickly inhabited and consumed by a variety of bacteria and wild yeasts. The goal of the brewer is to have the wort consumed (turned into beer) by a specific and isolated yeast strain which produces desirable flavors. The growth of any bacteria and most wild yeast strains will have a noticeable negative effect on beer quality, sometimes rendering it undrinkable. Proper cleaning and sanitation procedures can eliminate these unwanted microorganisms, allowing only the desired yeast to grow and thrive in your sealed fermenter. Cleaning and sanitation methods are not difficult, but their importance should not be underestimated. Most bad beer is the result of poor sanitation.

Two Distinct Operations:

In order to develop proper procedures it is first necessary to understand that cleaning and sanitation are two distinct operations. Cleaning is the removal of debris (and live organisms) using both chemicals and mechanical scrubbing. Sanitation is the use of chemicals to kill any remaining organisms. Unfortunately, the chemicals which are good at cleaning are generally not effective sanitizers and vice versa. A third term, sterilization, is often incorrectly used to describe this process. Sterilization is the complete elimination of outside microorganisms, and this not possible (or necessary) to achieve in your kitchen. A small amount of undesirable bacteria and wild yeast will remain on your equipment and live in your beer. But as long as their numbers are small and you pitch a sufficient dose of healthy yeast, their growth will be curtailed and your beer will not be adversely affected.

Though both of these operations are important, the greatest emphasis should be put on cleaning. Organisms are most likely to live in and around deposits, like foam and yeast residue, on your equipment. Sanitizing chemicals will only kill the organisms they contact, so anything living in and under remaining residues will be unaffected, left to grow and infect your beer. Therefore, you should make a habit of cleaning all of your equipment thoroughly, and the best time to do this is right after you finish using it. Deposits (like yeast sediment in bottles and foam residue around carboy necks) are easiest to remove when they are still moist. Then your equipment only needs a brief surface cleaning followed by sanitizing before use.

One of the most effective sanitizers you can use is heat, and this is fortunate for the brewer. The long wort boil is sufficient to kill just about any organisms introduced beforehand. Therefore, you need not worry about rigorous sanitation on anything used before or during the boil. But once the wort begins to cool, it is susceptible to infection. Anything that touches it from this point on should be thoroughly cleaned and sanitized.

Weapon #1: Cleaning Tools

The cleaning operation relies on mechanical action as much as chemicals, and you should have a good arsenal of tools to make cleaning easier and more effective.

- Brushes: A bottle brush is a great multi-purpose tool. It can be used to clean yeast deposits from bottles, scrub the insides of plastic fermenters, and scrub other items like spoons and wort chillers. It can even be used to clean blow-off hoses by tying a string to the wire loop on the handle and pulling it through the tubing. A large, curved carboy brush is essential for cleaning residue in carboy necks, and a small airlock brush can be used to salvage dirty airlocks.

- Sponges: A combination sponge/abrasive pad (Scotchbrite) is very versatile. The sponge side is great for general scrubbing and the abrasive side can be used to remove stubborn deposits. Don't use the abrasive on plastic items, though, because it will create scratches where microorganisms can reside.

- Bottle Cleaning Aids: A jet washer is a great accessory. It attaches to your sink and has an on/off valve. When you push your a bottle or carboy onto it, a high pressure jet of water is released, breaking debris loose and rinsing residual chemicals at the same time. Bottle rinsers are handy devices which quickly squirt sanitizer up into your bottles, eliminating the need to dunk them. Bottle drainers keep your bottling area tidy and make sure any residual chemicals drain out of your bottles, but be sure to clean and sanitize the drainer before using it.

Weapon #2: Chemicals

A large variety of chemicals are available for cleaning and sanitizing. Generally, the two are different. Some cleaning chemicals have limited sanitizing ability and some sanitizers offer limited cleaning power, but the best procedure is to use a strong cleaner followed by a highly effective sanitizer.

Cleaning Chemicals are all based on alkaline (the opposite of acidic) substances, which dissolve organic materials like yeast and hop residue. They feel slippery because they also dissolve your skin. Therefore, they can be dangerous and should be handled with caution. Some cleaning chemicals also employ detergents, which are not as harsh, to make them more effective. There are trade-offs in the use of these chemicals. The strongest ones will clean with little or no scrubbing, but they are dangerous. The milder ones require more physical effort, but they are safer. Large breweries find scrubbing to be time consuming and impractical, so they use strong chemicals, pumping them through enclosed Clean-In-Place (CIP) systems which are designed for safety. The labor of scrubbing homebrewing apparatus is minimal, though, so we can effectively use milder, safer chemicals. The necessary contact time for these chemicals varies. Allow your equipment to soak long enough for residues to soften and then scrub until they are removed. This may take as little as a few minutes or as long as a day for old bottles and carboys which weren't cleaned after they were emptied. Always follow cleaning with a thorough rinse. You know rinsing is complete when items are no longer slippery.

- Caustic is the common name for sodium hydroxide (caustic soda) and potassium hydroxide (caustic potash). These chemicals are strongly alkaline and are therefore very dangerous. They should not be used without hand and eye protection. Most effective when used in a hot (140-160F) solution, caustic is the cleaner most commonly used by commercial breweries. Highly corrosive, it should never be used on copper or aluminum. It is best avoided by homebrewers, but if you must, try a 2% solution, rinse very well with hot water, and then rinse with a mild acidic solution to neutralize the caustic.

- Trisodium Phosphate (TSP) is a mildly alkaline cleaning agent which is available at hardware stores and many homebrew shops. It is great for cleaning glass and removing bottle labels. Chlorinated trisodium phosphate (CTSP) has some sanitizing power as well because of the added chlorine, but it should not be used as your primary sanitizer. It is available at some homebrew supply shops. Use 1 tablespoon per gallon and rinse well with hot water. Wear gloves when using these chemicals.

- Soda ash, washing soda, and baking soda are various forms of sodium carbonate, a mildly alkaline compound. They are slow but effective cleaners which are best used warm. 1 tablespoon per gallon is sufficient in most cases.

- Ammonia is the active ingredient in many household cleaners and is very effective; but, it can leave harmful residues and should be avoided for brewing purposes. Never mix ammonia and bleach because they will react to form nitrogen trichloride, a very explosive chemical.

- B-Brite is a proprietary compound which contains a mixture of two cleansers. One is sodium percarbonate, which is similar to soda ash but has hydrogen peroxide added to it. (Hydrogen peroxide is an oxidizer which enhances cleaning ability and adds some sanitizing power.) The other is a detergent which provides a different cleaning action and acts as a dispersant to keep residue suspended in the cleaning solution so it can be rinsed away. It also acts as a corrosion inhibitor, which is good for any metal items. This combination of cleaners makes B-Brite very effective without the harshness of caustic. It has limited sanitizing ability, however, so it should be followed up with a good sanitizer. Use 1 tablespoon per gallon and rinse well with cold water.

A number of other chemical cleaners have come on the market in recent years which are similar to B-Brite in that they combine mild alkaline cleaners and various detergents. The main goal of these products is to provide brewers with cleaning alternatives that approach the strength of caustic but are not as dangerous and are effective at lower temperatures. They are sold under various trade names including Straight-A Cleanser, Powdered Line Cleaner (PLC) and Powdered Brewers Wash (PBW). These vary in effectiveness, but they are all well suited for homebrewing. Follow the instructions on the package.

Dish Washing Chemicals are inexpensive and effective cleaners. Liquid dish detergents are somewhat difficult to rinse and they can leave residues which harm head retention, so they should be used with caution. Granular dishwasher detergents are similar to B-Brite and the other proprietary chemicals in that they combine mild alkalines and detergents. They are formulated for electric dishwashers, though, so they may be difficult to dissolve in cold water. Some can also be harsh on the skin. Use 1 tablespoon per gallon and rinse well with hot water. Don't use any detergent which is scented because the aroma is hard to rinse away.

A number of no-rinse cleaners have come on the market recently. They are generally combinations of alkalines and detergents which are mild enough to not pose a health and flavor hazard if present in small amounts in your beer. Unfortunately, this means they also have a lower cleaning power than other chemicals. Homebrewers are better off using stronger cleaners, rinsing, and then using a sanitizer.

Sanitizing Chemicals kill bacteria and wild yeast on contact. They can also kill the yeast you pitch and cause off-flavors in your beer if not used properly. The best ones to use are those which are certified as sanitizers by the U.S. Government. This certification means that they will, when used in the proper concentrations, kill 99.9999% of the microorganisms which they contact within 30 seconds. There are a number of different types of certified sanitizers, but the ones most useful to brewers are called oxidizers. These are very reactive chemicals which attack microorganisms, breaking down cell walls and other tissue until the organisms are dead.

At this point, the brewer must consider the question of rinsing. Once your sanitizer has killed the microorganisms on your equipment you can rinse it off, risking contamination from your water source; or, you can leave it, risking off-flavors from the presence of sanitizer in your beer. Which sanitizer you choose will depend on which route you want to take. If you know your water is bacteria-free (most municipal water sources are) rinsing presents no problem. If your water is questionable, you either need a sanitizer which doesn't require rinsing or a sanitized rinsing agent (which I will discuss later).

The two most common oxidizing sanitizers used in brewing are chlorine and iodine, which both belong to the same chemical family, halogens. They are both very effective, but each has its drawbacks.

Chlorine is available as ordinary household bleach. It is actually sodium hypochlorite, which is one of the most effective sanitizers available. Bleach is made using caustic, and it actually has some residual caustic in it, which helps to keep it stable and gives it some measure of cleaning ability too. However, chlorine bleach does have a few drawbacks:

- Stabilization with caustic is needed because chlorine becomes extremely reactive in an acidic environment. It is more stable in an alkaline environment, but it can become relatively weak when diluted in alkaline water. NEVER ADD ACID TO BLEACH to try to increase its strength or for any other reason. If you do, the bleach will become dangerously reactive and may produce deadly chlorine gas. Also, NEVER MIX AMMONIA AND BLEACH, because an explosive mixture will be formed.

- Chlorine bleach loses its strength over time. Six-month old bleach has half the strength it did when it was made.

- Chlorine bleach is very corrosive. It will cause damage to stainless steel, copper, or aluminum.

- If present in significant amounts in your beer, chlorine will react with tannins from the grains and hops to form chlorophenols, which have a strong, unpleasant, medicinal flavor.

- If spilled, it can bleach the color from your clothes or carpeting.

In spite of these drawbacks, (unscented) chlorine bleach is a useful sanitizer because it is inexpensive, readily available, and usually very effective. It will sanitize in 30 seconds at a concentration of 200 ppm (about 1 tablespoon per gallon). However, it requires thorough rinsing with hot water at this concentration. At 20 ppm (about 1/3 teaspoon per gallon), it does not require rinsing, but needs about 30 minutes of contact time to be effective. Chlorine is also available in granular form under the trade names CL-9 and C-Brite.

Iodine is the sanitizer of choice in many commercial breweries. It is commonly available as iodophor, which consists of iodine attached to detergent-type organic carriers. Iodophor is made by one of two processes. Hot process-iodophor requires an acidic environment to release its iodine, so it contains some proportion of acid, usually phosphoric (thus the ame: iodo-phor). Cold-process iodophor contains no acids and it is not so pH sensitive. It also foams less than hot-process iodophor. You can tell which type a particular brand is by looking at the ingredients. If it contains an acid, it is hot-process iodophor. (BTF and BEST are both cold-process iodophors). Both types are very effective, but their acid sensitivity can cause problems. Like chlorine bleach, iodophor becomes less active at higher pH, but it doesn't exhibit chlorine's low pH instability, so you can add acid to it. Hot-process iodophor is more pH sensitive than cold-process. If your water is alkaline (pH>8), use cold-process iodophor. If it is very alkaline (pH>9), add some acid to your sanitizing solution (3 drops of 85% phosphoric or 1/4 tsp citric per gallon should be sufficient) to increase its effectiveness.

Iodophor has two main advantages over bleach. It is not corrosive to any brewery materials and is effective at lower concentrations. At 25 ppm (1 teaspoon or 1/5 oz. per gallon), it requires one minute of contact time. For those who don't wish to rinse, you can safely use 12.5 ppm (1/2 tsp or 1/10 oz. per gallon), but the contact time should be increased to 5 minutes. Iodophor leaves deep reddish-brown stains if spilled.

Sulfites are commonly used both as a sanitizer and additive in winemaking. They work by releasing 502 gas and are available either as sodium metabisulfite or potassium metabisulfite. They are sold either as a powder or as campden tablets. Sulfites are mild oxidizers which are useful in winemaking for reducing oxidation during storage, inhibiting bacterial growth, and inhibiting refermentation in finished wine. However, their oxidizing power is only sufficient to discourage the growth of microorganisms. It will not kill any yeasts or bacteria which are already present. For wine, which also discourages infection with high acidity and alcohol levels, this is sufficient. But sulfites are not strong enough to be used as sanitizers for brewing.

Heat is an extremely effective sanitizer which is sometimes used by large commercial breweries, in the fomm of steam, to sanitize fermenters and other vessels. One minute at 150F (or 5 minutes at 140F) is sufficient to completely kill the wild yeast and bacteria typically found in beer. Unfortunately, steam is not readily available to the homebrewer but other forms of heat are. The hot-dry cycle of an electric dishwasher is an effective way to sanitize bottles and other non-plastic brewing items. Don't use detergent, though, because it may not get rinses from the insides of the bottles. If your machine has a rinsing agent, remove it because it will cling to your bottles and cause head retention problems. Another heat source which can be useful is your hot water heater if your tap water may have contamination problems, turn up your water to get an output temperature of 140-150F. The time the water spends in the heater should be sufficient to sanitize it. Now you can use it as comamination-free rinse water, but be careful and wear gloves, 140F water can cause painful burns.

Ethyl alcohol in the form of vodka and grain alcohol is a good, but expensive, sanitizer. It can be used in cases where the sanitizer may go directly into your beer. It is good for sanitizing the openings of carboys and yeast culturing containers, or for filling airlocks.

Most of the other government certified sanitizers are not suited to brewing for a variety of reasons, but chemical manufacturers are constantly developing new products. Two which have appeared recently are acid-anionics and chlorine dioxide. Acid-anionics are essentially a strong acid (like phosphoric) combined with a wetting agent. Though they are effective, these strong acids are dangerous for homebrewing use. Chlorine dioxide works by breaking down cell wall proteins it requires an acidic solution to be effective, so it must me dissolved in water along with a small amount of an acid like phosphoric or citric. Its major benefit is that it is effective at 10-15 ppm and at this concentration, rinsing is not necessary. A number of commercial brewenes have begun using chlorine dioxide and the results sound positive. Chlorine dioxide can he found at some homebrew supply stores under the trade name Oxine. Follow Ihe instructions on the package.

(NOTE: The contact times given for each of these chemicals are the minimum required for an effective kill. In practice, increasing these times is a good idea because it gives you an extra measure of security.)

What Should You Do? It should be obvious by now that there are many options. Fortunately, most of these products work well if they are used as intended. The methods and chemicals you should use depends on what products are readily available to you, how comfortable you are with using strong chemicals, and the quality of your tap water. Here are some recommendations:

- Clean all of your equipment thoroughly after using it. Use a good, strong cleanser like B-Brite or Straight-A and as much scrubbing as necessary. Rinse well with warm water. Avoid caustic cleansers. They are very dangerous, and unless they are used very hot, they aren't any more effective than the milder, brewing-formulated sanitizers.

- Keep your brewing and fermenting areas very clean to reduce the likelihood of airborne contaminants contacting your beer.

- When you're brewing, reclean any items that look like they need it and rinse well with warm water.

- Sanitize any items which will touch your beer after the boil.

The best all-around sanitizing agent for home brewers is iodophor. If your water is sanitary, use a 25 ppm solution and rinse. If you are not sure about your water, use a 25 ppm solution and rinse with very hot water. If you know that your water is horribly contaminated, use a 12.5 ppm solution (made with bottled purified water), increase your contact time and don't rinse.

If you want to use bleach for a sanitizer, a 200 ppm solution is best, but you must rinse very well with hot water. If your tap water is contaminated, you can use a 25 ppm solution (made with bottled purified water) and not rinse, but a 30 minute contact time is needed for effective sanitation.

If your tap water is highly contaminated, but you still want to rinse, consider a sterile beer rinse. Most cheap mass-market beer is pasteurized, so you can use it to rinse. Go buy a couple of quarts of your favorite malt liquor and have at it.

Remember that sanitation requires contact, not necessarily immersion. You don't need 6 gallons of solution to sanitize your bucket. You can make only two gallons and slosh it around on the sides.

- If you have an automatic dishwasher, use the hot-dry cycle to sanitize your bottles, but don't heat or boil your bottle caps. This can damage the rubber lining and the caps may not seal. Sanitize your caps chemically.

- Periodically replace plastic items like buckets and hoses. They are likely to get scratched and stained, so they will eventually become contamination risks.

- If you end up with an infected batch, thoroughly scrub every piece of brewing equipment you own, then soak it all overnight in sanitizer before using it again.

Next Issue: Kegging your Homebrew

Dave Bone has been brewing for over eight years and is the founder of Austin Home Brew Supply.