Q Are cleaning and sanitizing the same thing?
A When it comes to this topic, there are two classes of chemicals: cleaners and sanitizers. Cleaners are formulated to remove soils. Some cleaners, like sodium hydroxide, are also lethal to microorganisms, especially when the cleaner contains sodium hypochlorite (bleach). However, these cleaners typically do not guarantee a sanitized surface. Sanitizers are designed to kill microorganisms, and some sanitizers are more effective at killing yeast than bacteria. Most sanitizers do not work well if the surface is dirty; they are best used after a thorough cleaning step. The best sanitizer is hot water or pressurized steam coupled with time. Many people assume that very low temperatures accomplish the same thing, but this is not true. Bacteria and yeast easily survive freezing, even for long periods of time.
Q What cleaning supplies do I need?
A The cleaning supplies used for homebrewing fall into two categories: household cleaners and specialty cleaners. I suggest selecting one all-purpose cleaner for all equipment. A dish detergent can be used to clean brewing equipment, but many of the soils found in the brew kettle and fermenter are not so easily removed. If you use a gentle cleaner, you will need to use brushes and elbow grease to clean your equipment. It is very important not to use implements that may scratch your equipment. Scratches make equipment more difficult to clean over time.
Personally, I like stronger alkaline cleaners, such as sodium hydroxide and sodium metasilicate, with good dissolving power, as my go-to cleaners. I periodically use acid cleaners to remove mineral deposits and beer stone. After the equipment is cleaned, I sanitize it with hot water or one of the many food-grade sanitizers on the market.
The only other special thing you need to clean homebrew equipment is an appropriately large container to soak and rinse equipment. Unless you have a really big kitchen sink, you may find that the bathtub or laundry sink is a better place to do some of your scrubbing. Plastic 55-gallon (208 L) chemical drums cut in half are pretty handy makeshift cleaning tubs and can also be used to ice kegs.
Q What are the different types of cleansers available, and how should they be used?
A Sanitization is one of the most important things a brewer can do to ensure good beer. I believe in and practice rigorous sanitization methods when I brew. Many brewers fail to recognize the cleaning component of a sanitization program. To properly sanitize any equipment used for food or beverage handling, the item must be cleaned first.
Cleaning means that organic debris is loosened and removed from the surface prior to using a sanitizer. Cleaning increases the effectiveness of your sanitizer, because organic debris consumes the sanitizing power of most chemical sanitizers. Just as a shield can fend off the blows of a sword, organic debris can prevent microorganisms from coming into contact with sanitizing chemicals. In fact, many microorganisms secrete extracellular slime that helps them attach to surfaces and protects them from chemical sanitizers.
Cleaning also drastically reduces the microbial load. In other words, cleaning washes microorganisms away. Most dishwashing detergents used in the home do not contain sanitizing agents and effectively remove microorganisms from smooth surfaces simply by acting as a detergent (known in cleaning lingo as a surfactant).
In practice, sanitizing should serve as an insurance policy to good cleaning. The fact is that a properly cleaned, unsanitized piece of equipment could most likely be used with minimal risk of contaminating the brewery. Many common cleaners used in the brewery, such as hot sodium hydroxide, or caustic soda, will also kill microorganisms. Do an excellent job cleaning your equipment and use a sanitizer as a second line of defense to your cleaning. For the record, I recommend sanitizing everything that touches beer or wort after boiling.
There are many good cleaners. The safest is a good dishwashing detergent coupled with elbow grease. Other cleaners, such as trisodium phosphate (TSP) and sodium hydroxide, have the added advantage of dissolving soils, but they are also less safe to handle. Certain mineral soils, such as beer stone, are not soluble in alkaline cleaners like TSP and sodium hydroxide. Acids such as white vinegar effectively remove mineral deposits. I keep a gallon under my sink and use it to clean everything from hard water spots in the bathroom to my coffee maker. You can use just about any chemical cleaner on your brewing equipment as long as you thoroughly rinse it from the equipment before the sanitizing step.
One last piece of advice: Don’t rinse “no-rinse” sanitizers. Rinsing water can contain spoilage organisms and undo all your work. As long as the sanitizer is diluted as directed on the product bottle, you should have no reason to rinse your equipment after cleaning and sanitizing.
Q What makes a good sanitizer for my equipment?
A Sanitizers that brewers use have some common traits. The best sanitizers do not affect beer flavor or foam stability, are cost effective, and are not toxic when used at the proper concentration. Food-grade sanitizers that meet the requirements include sodium hypochlorite (bleach), iodophor solutions, peroxyacetic acid (my favorite), quaternary ammonium compounds (quats), and hot water or steam. Bleach can cause off-aromas and damage stainless steel if used incorrectly, but it is a great sanitizer and is safe. Iodophor can also lead to off-flavors, and quats are notorious for ruining foam.
Stronger alkaline cleaners. Sodium hydroxide and sodium metasilicate, with good dissolving power, are my go-to cleaners.
Acid cleaners. I periodically use acid cleaners to remove mineral deposits and beer stone. My favorite acid cleaner to use at home is white vinegar. I keep a gallon under my sink and use it to clean everything from hard water spots in the bathroom to my coffee maker.
Sanitizers. My advice on sanitizers is to keep more than one type on hand. Quaternary sanitizers are great for certain tasks, while peroxyacetic acid (PAA), iodophors, bleach, and hot water work great for others.
Q Everybody talks about bleach, iodine, and commercial products as a sanitizer. What about alcohol?
A Alcohol is a great sanitizer; its most effective concentration for use is 70 percent. Many brewers use rubbing alcohol (isopropyl alcohol) in a spray bottle to spray valves, small fittings, and the like before use. Rubbing alcohol is a very effective sanitizer but is not intended for consumption. You don’t want any appreciable amount of isopropyl alcohol in beer. Rubbing alcohol is much more toxic than ethanol, the kind of alcohol we homebrewers make, but it’s not highly toxic in small doses, like methanol (wood alcohol).
I use isopropyl alcohol to sanitize sample devices, keg valves, and certain pieces of bottling equipment prior to use. I let the alcohol evaporate before using these implements, and I always flush beer through surfaces sanitized with alcohol before running the beer into a bottle or keg. The bottom line is that rubbing alcohol is not a food-grade sanitizer and should not be used for sanitizing fermenters, transfer lines, and other pieces of brewing equipment.
Ethanol is also a very effective sanitizer at the 70 percent (140 proof) concentration. However, it is expensive because it is taxed. Industrial-grade ethanol is cheaper than beverage ethanol, because methanol is added to the industrial version to make it toxic if consumed, thereby eliminating the taxes placed on beverage ethanol. Do not use industrial-grade ethanol for anything to do with brewing or cooking!
You can use alcohol for a sanitizer, but if it is likely to end up in your beer, you need to use ethanol and not isopropyl alcohol. As a closing comment, homebrewers typically follow the trends used by commercial brewers. Commercial brewers would probably not use ethanol even if it were cheap as a sanitizer, since it is flammable and electrical equipment (pump motors, light switches, and in-line instrumentation, for example) gets much more expensive when designed as “explosion proof” or “intrinsically safe,” as is required for use around flammable liquids and gases. If you want to use alcohol at home for sanitizing, go for it!
Q When is it appropriate to use bleach and when is it not?
A 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 a defect in all beer. Avoid this particular problem by keeping 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 you might have chlorophenol problems without using a bleach sanitizer — but this is another issue. I prefer using compounds other than bleach for sanitizing. My favorite is peroxyacetic acid (PAA).
Bleach is a strong oxidizing chemical and works extremely well as a sanitizer and as a cleaner. In fact, adding bleach enhances many industrial caustic cleaners (usually sodium hydroxide). These so-called chlorinated caustics are much more effective in the removal of protein films than regular caustic, and many brewers use them 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). Caustic cleaners are alkaline and have a high pH, so stainless steel can be safely cleaned with 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 do use bleach, I recommend cheap bleaches that contain only sodium hypochlorite. Avoid bleaches such as lemon-scented Clorox. Bleach works great for soaking hoses, cleaning glass, and 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 builds over time in our whirlpool. This film accumulates despite the fact that we clean our whirlpool with caustic after every use. Do not use bleach as an everyday stainless cleaner, because of its potential corrosive-ness. 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 2 teaspoons of bleach per gallon [10 mL/3.8 L]). The Montana State University Extension Service Web site recommends 50 ppm for household sanitation of dishes and 100 ppm for sanitizing countertops and appliances. Cleaning is another issue — concentrations from 6 to 12 ounces per gallon (47–94 mL/L) of water are more common. When I add bleach to caustic, I add about 12 ounces of bleach to 2 gallons (355 mL/7.6 L) of a 2 percent caustic solution. That’s one potent cleaner!
Q Is sanitation important during mashing and sparging?
A Sanitation is very important in every part of the brewing process. During wort production, it is important that your homebrewing equipment start off clean, like plates stored in your cupboard. The only time microorganisms really cause problems in the brewhouse is when wort sits around long enough that it starts to grow bacteria. This is uncommon at home, but it happens in commercial breweries where cleaning is more challenging. I read many recipes stressing the importance of sanitizing all brew pots, mash tuns, and tools, but it is not necessary. What is needed is for these brewing implements to be clean.
As soon as the kettle boil is over and wort cooling begins, the rules change. This is because wort is a nutrient-rich liquid that can support the growth of just about anything that falls in. Sanitizers (such as hot water, iodophor, and bleach) actively kill anything on your equipment to ensure it doesn’t make it into your wort and spoil your beer.
Q What is the best way to clean and sanitize a plastic fermenter?
A Be careful cleaning your plastic. Extremely stiff bristles safe for glass carboys can scratch plastic if applied with force. Some brushes use a twisted wire design to hold the bristles together and act as a handle; this can scratch surfaces. Scratches provide future safe havens for all kinds of microscopic contamination. If you simply want to swab the sanitizer across the surface of your equipment, use one of the sponges with a plastic handle used to clean glasses. Then you will not have to worry about scratches. Another problem with plastics is their ability to hold aromas. As a result, be careful using chlorine bleach products.
Q A homebrewer told me that as long as bottles were clean and free of residue, they could be sterilized in the oven. His method was to stack the bottles in a cold oven, bring it to near 500°F (260°C) and then let it cool gradually, removing the bottles when completely cool. Have you ever heard of this method, and does it produce good results?
A Dry heat, like that of an oven, is not as effective as moist heat when it comes to killing microorganisms. Sterilizing devices, like autoclaves and pressure cookers, use steam for heating and are vented during the heat-up phase to eliminate air. Air acts as an insulator in steam sterilizers and slows down heat transfer from the steam to the item being sterilized. Items — such as surgical instruments or lab waste — usually become sterile after 20 minutes in a pressure cooker or autoclave held at 15 psi. The method you describe can be used, but the sterilization time required is longer than if you used steam. Unfortunately, I cannot find any solid numbers for exactly how much time is required, since all of my references related to heat sterilization are based on moist heat. I would guess that 30 to 45 minutes of dry heat exposure would be pretty effective at killing beer spoilage bacteria and yeast.
There is a practical problem to heating beer bottles: glass fatigue. At one time in my brewing career, I sterilized bottles in a steam cabinet (basically an unpressurized steaming device similar to a big seafood steamer). After several cycles, the bottles became weak, and one day, several exploded during counterpressure filling. Luckily, I was wearing a face shield. After that experience, I quit using heat to sterilize bottles.
My advice about bottle cleaning and sterilization is to begin with clean bottles. If you reuse your bottles, thoroughly rinse them immediately after use. This makes cleaning much easier when you need a batch. Some dishwashers accommodate bottles and do a good job of cleaning them. Or you can soak bottles in a hot, diluted solution of a heavy-duty cleaner such as sodium hydroxide or sodium metasilicate. If the bottles are already pretty clean, hot dish soap will work fine. The idea with cleaning is to remove organic soils that interfere with the activity of most sanitizers.
After cleaning and rinsing, I prefer to use a liquid sanitizer instead of heat. One way to do this is to soak the bottles in your sanitizer of choice; chlorine bleach and iodine solutions are two popular choices for homebrewers that, if allowed to dry, should not impart aromas. (See chapter 7 for more information.)
Q What sanitizing solution is friendly enough for a septic system?
A There are many different sanitizers available to home-brewers. In your particular case, you want a sanitizer to effectively kill bacteria and wild yeast that may spoil your beer. But you don’t want to kill the bacteria — at least not too many of them — that make your septic system function.
I don’t know the size of your septic system, but in all likelihood, you could use just about any sanitizer available on the market to sanitize your homebrewing tools without harming the septic system. Since most sanitizers work by chemical oxidation, they lose their sanitizing ability after they have done their oxidation dirty work. This is why using a sanitizer such as bleach on a dirty surface doesn’t guarantee success; the dirty surface uses the oxidizing potency of the sanitizer before the sanitizer kills the bugs. The amount of oxidizable matter in the drain line between your home and your septic tank will probably take care of most sanitizers that you might use.
Chemical cleaners are a different matter, especially those cleaners containing phosphates. Most states have laws regulating the types of soaps and detergents that are permissible for sale; many soaps are especially designed for septic systems. Detergents are designed to wet surfaces and carry crud away from the surface. They include chelating agents that make them foam, even in the hardest of waters. In the scheme of things, soap selection is much more important to your septic system than sanitizer selection.
Although I probably sound like a card-carrying sanitizer abuser, I don’t like chemical sanitizers for a set of different reasons. The only way to really sanitize anything effectively is to apply the sanitizer as the last step of the cleaning process. Last means last and leaves no room for a water rinse — especially well water! Many people have the notion that water is somehow bacteria-free purity flowing freely from the taps of their homes. As nice as the concept sounds, tap water carries no guarantee of being free of bacteria. In most cases, it probably doesn’t carry the bacteria that spoil beer, but when it comes to cleaning procedures, “probably doesn’t contain” translates to “may contain.”
I don’t like many of the sanitizers (such as bleach) commonly used by brewers because they affect the beer flavor and appearance when left on the surface of the item being sanitized. Some make the beer taste medicinal, and many ruin its foam. We use sanitizers to keep the beer free of bacteria, but if it ends up with a different problem, what’s the point? Funky beer is funky beer.
The two nonrinse sanitizers I really like for sanitizing the big items, such as fermenters and hoses, are peroxyacetic acid (PAA) and hot water.
Peroxyacetic acid leaves no foreign by-products and has gained popularity with commercial brewers. It is a combination of hydrogen peroxide and acetic acid. The sanitizer is stable in the absence of oxidizable matter but breaks down into peroxide and acetic acid when exposed to organic debris. Assuming the item being sanitized is clean, the organic debris is probably some microbial bug rapidly killed by the very aggressive peroxide component. The ultimate by-products of PAA are water and acetic acid (vinegar). Spoiled beers often have high levels of acetic acid, but all beers contain a very small amount.
Hot water is also a wonderful sanitizer for brewing equipment. Nothing destroys microorganisms like wet heat. The rule of thumb for killing beer spoilage organisms with hot water is 20 minutes at 180°F (82°C) or hotter.
Q After I empty my bottle into a glass, I fill the bottle about three-quarters of the way with warm water, turn it upside down, and shake it vigorously while it drains. Then I repeat this procedure. I park the bottle upside down to dry and then store in the case, again upside down. At bottling time, I just use my bottle tree to let the bottles dry after dousing the inside with iodophor solution. Is what I am doing adequate, or is there a big potential for a problem?
A Remember, there are two stages to cleaning when it is applied to food or beverage implements: cleaning and sanitizing. Cleaning is simply the removal of debris, usually organic in nature, from the surface of the object being cleaned. Sanitizing is used to kill yeast or bacteria that may spoil beer or food. Cleaning usually begins with a rinse to remove loose debris. Your warm water rinse falls into this category of “prerinsing.”
The next step is to use some sort of energy input to remove soil that remains on the item being cleaned. There are three modes: mechanical, thermal, and chemical. For example, when you wash dishes with hot, soapy water you are using 1) elbow grease or mechanical energy, 2) hot water for the thermal factor, and 3) soap as a chemical cleaner. This step is critical because organic (schmoo) and inorganic (beer stone) components in beer adhere to surfaces and are largely unaffected by rinsing, even in cases where the object looks clean!
This is not to imply that prerinsing is not important. If loose soils are not removed before cleaning, they will reduce the cleaning power of your cleaner. Those dishwashing liquid commercials that show greasy plates being dunked into the dishwater are the perfect example of how not to clean. This does nothing more than make the cleaner less effective for the next greasy plate until the cleaner becomes so dirty that it begins to make the surface dirtier than it was before cleaning. Believe it or not, this actually happens; cleaning gurus call it redeposition.
After cleaning, it is then time to use a sanitizer. This segregation of duties is important because most sanitizers work by oxidizing things. If the sanitizee is clean, then the stuff being oxidized is most likely very tightly adhered to the sanitizee surface. The only things routinely left after cleaning are bacteria that form tight bio-films on surfaces. This is what the sanitizer is intended to oxidize. If the surface still has other organic debris, then the sanitizer will be used up on the remaining crud.
I think your prerinsing of bottles is an excellent start, because it prevents beer schmoo from drying on the surface. I would not consider this surface clean enough to be sanitized. I would strongly recommend cleaning with detergent between your water rinse and iodophor application. If I were doing the work, I would accumulate prerinsed bottles over time, clean them all at once, and then sanitize immediately after cleaning to make the work more efficient.
Q 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?
A 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. Iodophors require no more than 30 minutes to effectively sanitize a surface at the recommended concentration of 25 ppm. Most iodophors are diluted so that the typical use rate is somewhere around 1 ounce per gallon (7.8 mL/L). They are always labeled with instructions giving suggested usage rates. If you use it at this concentration and allow your equipment to drain properly, 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.
Q I have heard that some brewers soak their bottles in iodophor and place the bottles on a tree to drip dry and use them up to a week later. Would you recommend a bottle tree?
A Your primary concern with the use of bottle trees is the issue of recontamination. Any sanitized surface can be contaminated after the sanitizing step, and contact with contaminated surfaces should be eliminated. Using a bottle tree does not necessarily pose a risk if the tree is kept clean and sanitized. If you soak your bottles in the iodophor along with the tree and place them to drain on the tree, you should be fine. But I would not wait a week until using them. After the bottles drain on the tree, they should be used immediately because iodophor sanitizers work on contact and have very little residual activity.
Q I would like to know if I can use a quaternary sanitizer to sanitize homebrewing equipment. This stuff is used in the food industry as a no-rinse, air-dry sanitizer. I don’t want to ruin a batch of beer if it is inappropriate to use in homebrewing.
A Quaternary ammonium compounds, frequently called quats or QACs, are effective no-rinse sanitizers used in the food industry for a wide range of purposes. Quats are natural wetting agents and are very similar to soap. This means that they are good at penetrating surfaces.
Quats kill a wide range of bacteria and also leave a bacteriostatic film on surfaces. This film prevents microorganisms from recontaminating a previously cleaned and sanitized surface. Quats are frequently used to prevent the growth of microbes, especially molds and mildews, in food-processing areas. Restaurants also use quats in sinks as the final dip for dishwashing. This practice is used to wash glasses in bars.
Quats are gentle on the skin, stable when stored, and maintain their effectiveness when exposed to organic soils (dirty equipment). They also leave no odor or flavor on equipment or glassware. So far, quats are sounding pretty good, but there’s a catch.
In general, brewers don’t use quats on beer contact surfaces because quats can ruin beer foam. It’s unfortunate that many bars and brewpubs use quats in their glass-washing sinks. That said, I do use quats in a fittings soak tank for small items and also use them to sanitize hoses and pipes. When used for hoses or pipes, I also rinse the quats out with clean water before passing beer through the line so the foam won’t be destroyed.
Quats can be used to sanitize fermenters and other beer vessels, but I don’t recommend them for these applications. Personally, I use a sanitizer called peroxyacetic acid (PAA) for beer vessels because it’s effective and leaves nothing but water and vinegar (acetic acid) on the surface. (See sanitizing with PAA, page 90.)
My advice on sanitizers is to keep more than one type on hand. Quaternary sanitizers are great for certain tasks, while PPA, iodophors, bleach, and hot water work great for others. Just like household cleaners, one sanitizer is never going to be the best choice for all circumstances.
Q Are there any cleaners I need to avoid using on my new stainless steel pot?
A The one commonly used household chemical that can really damage stainless steel is bleach. Bleach (sodium hypochlorite) is corrosive to stainless steel when the pH is less than about 12 and causes the steel surface to develop small pits. Eventually, the pits can turn into holes, transforming a pot into a strainer. Pits are also hard to clean and can be a place for bacterial contaminants to hide.
Q How do I clean my stainless steel brew kettles?
A For those of you with expensive stainless steel cookware or brew kettles, here is some money-saving advice. DO NOT use any metallic abrasive pads when you clean. That includes 3M green scouring pads, copper balls of metal, stainless balls of metal, and all metal tools. (By the way, 3M makes many of the polishing abrasives used by stainless companies, but they are much finer than the pads used to remove cheese from a casserole dish.)
I recommend using Teflon scouring pads that are far too soft to scratch the surface of stainless steel vessels. We use a product made by 3M called a Doodlebug mop to clean the outside of our fermenters. It’s a snazzy tool that has a big pad (which looks like one of those buff puff facial pads) stuck on its end. Again, the key is using something that does not scratch!
When there is a big cleaning problem, I am a proponent of chemical cleaners. What you want to do is select a cleaner that will dissolve the soil and not damage the steel. Although chlorinated cleaners can be used safely on stainless steel, I usually discourage their use because they can cause damage if used inappropriately. Cleaners like powder brewery wash (PBW) and sodium hydroxide, or caustic (my favorite), are good at dissolving soils. The key is to allow the chemicals to do the work for you. It is very important to wear eye and hand protection when working with industrial cleaners — even if you use a brush (metal free, of course) to do the scrubbing, since brushes have a way of spitting stuff toward one’s face. Information abounds about cleaning chemicals, so I will be brief here. My point is that chemicals should be used on dirty equipment — not drills with abrasive scrubbing attachments.
And finally some words on passivation: This term describes a very particular type of cleaning performed on stainless steel. The main goal of passivation is to remove all contaminants (oils, soils, and especially, iron) from the surface of stainless steel in order to allow the “passive” film of chromium oxide (that makes stainless steel “stainless”) to form spontaneously. The only chemicals widely used for this task are nitric acid and hot citric acid. Nitric acid is extremely dangerous, and the citric acid method is pretty intricate. In any case, you really don’t need to worry about passivating stainless steel unless you contaminate the surface with iron. A rust-producing abrasive or tool is actually one of the best ways to go about contaminating the surface with iron, so this is another good reason not to use metal for cleaning.
Q I’ve read that the best way to sterilize my copper immersion wort chiller is to put it into the boiling wort for the last 15 minutes of the boil. When I do this, my boil stops and it takes 10 minutes to start up again on my electric stove. Is this normal, and are there other ways to sterilize the chiller?
A Using the wort boil to sanitize your wort cooler is really the easiest and most effective method. To ensure you get your proper boil time, knowing your chiller will stall the boil, you could simply extend your boil by 10 minutes before adding the coil. Try preheating the copper coil in a pot of boiling water. Copper has excellent heat-transfer properties, which means it doesn’t take very long to preheat. The stalled boil is common when adding a copper chiller, because the copper absorbs energy from the wort faster than your stove burner can transfer energy to your brew pot. If you want to use a chemical sanitizer instead, make sure it is a sanitizer with a low pH, such as iodophors and quaternary ammonium compounds (quats); they are copper friendly and won’t cause corrosion. (Read more about quats for sanitizing on page 101.)
Using a sanitized immersion wort chiller
Q I discovered that my copper counterflow chiller fits inside my pressure cooker. To sanitize, or actually sterilize it, I will run it through at 10–15 psi for about 15 minutes. Can this be harmful to my brew or me?
A Pressure cookers are wonderful discoveries, especially if you name them something else. I call my pressure cooker an autoclave. Autoclave sounds less like some pot that granny used to make pot roast or can green beans from the garden. I use my autoclave to sterilize wort, contained in little Erlenmeyer flasks, and media bottles to grow yeast. The autoclave is also great for sterilizing media to make Petri dishes containing various microbiological media. And of course, when one considers that surgeons sterilize scalpels, forceps, hemostats, sutures, and all sorts of other surgical implements in autoclaves, they become an obvious tool for use in a brewery.
Autoclaves can sterilize if the steam pressure (temperature) and duration of the process are sufficient. Usually when equipment is sterilized, the process is targeted to destroy a specific group of bugs, and the term “commercially sterile” is used since absolute sterility is not practical. Some heat-resistant spores, such as Clostridium botulinum, are very difficult to destroy. Those spores can kill people if canned foods are not properly processed. Beer does not support the growth of pathogens, but heat-resistant bacteria certainly can make for some awful tasting beer. Heat exchangers are a good place for these little buggers to hide.
Cleaning beer and wort lines is also very important. At our brewery, the wort line is cleaned after every brew and heat-sanitized by recirculating 203°F (95°C) water through the line for at least 20 minutes. We do the same thing with our beer filter. We measure the water temperature at the outlet of the filter and maintain a minimum temperature of 176°F (80°C) for 20 minutes before we cool the filter with cold water that was previously boiled. Heat is a wonderful method of killing bacteria because bacteria cannot hide from heat, provided that the heat is uniformly distributed through the equipment being sanitized or sterilized.
When equipment is exposed to very hot water or steam, as in an autoclave, it is important to verify that all parts can tolerate high temperatures. Heat-treating materials not rated for extremely high temperatures can result in failure. If the piece of equipment being treated is to contain something potentially dangerous, like hot wort, a failure can cause serious injury.
Make sure your chiller or any other equipment you choose to put into the pressure cooker has no plastic parts that might not be as heat tolerant as they need to be and end up harming the chiller or causing flavor problems in your beer. You should note that hoses are rated for specific pressures and temperatures. These two numbers mean that a hose can hold, for example, 100 psi of pressure at 120°F (49°C). The rating does not mean that the hose melts above 120°F (49°C), but that it may burst if pressurized above 100 psi at the same temperature. When heat sterilizing in an autoclave, you really don’t care about the pressure rating, because you are not using the hose to hold liquid pressure. You do want to ensure that the hose is not damaged. Simply remove the hose and autoclave the chiller if you cannot determine the hose’s temperature rating. When I autoclave things, I use 15 psi for 20 minutes, and most home pressure cookers have a weight designed to provide 15 psi of steam pressure. The time and temperature used in an autoclave depends on what bugs you are targeting. You can get data on the kill rate of various bacteria at different temperatures if you so desire.