Sanitary Testers: ATP Theory

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What is ATP and why is it used as an indicator of sanitary quality in brewing and draught beer systems?

ATP, short for “adenosine triphosphate,” is a high-energy molecule that stores energy in cells, and consists of adenine, a ribose sugar, and three phosphate groups (Timberlake, Structures of Life, 2nd ed., 2007). ATP, because of its prevalent role in cellular metabolism, is a highly ubiquitous biomolecule that is produced by nearly every living cell of every species. It is the carrier of chemical energy that fuels the majority of anabolic reactions within an organism to maintain metabolic balance.

How does cellular metabolism and ATP production relate to brewery and draught beer sanitation?

The theory applied to the use of ATP as an indicator molecule for sanitary quality is based on well-accepted scientific knowledge that every living cell must produce ATP to stay alive; therefore, ATP levels should correspond to the number of bacterial cells living in a sample of beer. But it is important to understand that electronic ATP testers are only able to detect ATP and CANNOT detect bacterial cells.

Since the development of ATP sensors for detecting bacterial levels beer, much has been learned about bacterial life cycles and the efficacy of ATP for quantitative analysis. Recent biochemical and microbiological research has indicated that ATP levels do vary with cell count, but population size is not the primary determinant of ATP levels. ATP concentration varies depending on a number of environmental factors unrelated to bacterial population size.

Factors Affecting ATP Test Results:

ATP is a nutrient. Cellular processes have evolved in ways that efficiently support life. Because ATP is critical to the health of a living organism, bacteria prefer not to export ATP out of the cell. Nearly all ATP, like any nutrient, will remain inside of the cell (intracellular) until it is digested during regular cellular metabolism and excreted as waste.

Cells of any species have enzymes and organelles that precisely orchestrate the uptake of useful chemicals and nutrients into the cell, while ensuring effective digestion and release of waste products and toxins out of the cell.

In a study performed at UCLA and Berkeley, extracellular ATP concentrations among Salmonella and E. coli test strains showed to vary from 1-30 nanomoles during growth and stationary phase, and extracellular ATP actually decreased during stationary phase—when cell count is highest (Mempin, Release of extracellular ATP during growth, BMC Microbiology, 2013).

The ATP that is detected by an ATP tester is a tiny portion of the total ATP that exists in any sample of beer. The ATP sensed by the chemical probe of an ATP tester results from extracellular ATP release which will vary independent of population size—as much as 30-fold—during the life of a bacterial colony. The great majority of ATP exists intracellularly and is not accessible to a sensor or probe. Consequently, ATP test results do not provide an accurate measurement of total ATP or the concentration of viable bacterial cells in a sample of beer.

Life Cycle

The bacterial life cycle is complex. Understanding the build-up, maintenance, and subsequent destruction of bacterial cells and colonies is obviously a very important area of scientific research. These topics involve everything from antibiotic development and public sanitation to environmental bioremediation and ecology. Microbes are everywhere, and the mysteries of their existence have been under investigation since Louis Pasteur’s discovery of single-celled organisms in 1860. Bacteria continue to evolve and scientists continue to reveal their phenomenal strategies to maintain health and reproduction.

The life cycle of a bacterial cell, like any living organism, has a natural rhythm and sequence of events—it is produced by the division of a parent cell, daughter cells undergo growth and maturation, then reproduce or die. But this ideal framework for understanding bacterial life is averted when environmental fluctuations stimulate bacterial survival strategies that drastically alter the metabolic activities and physical composition of bacterial cells and colonies.

Sugar

One of the most important environmental factors that affects cellular metabolism is the availability of nutrients. Cells will oscillate between a healthy, “well-fed” state and a starvation state. These conditions direct metabolic responses from the cell involving ATP production and consumption. One of the most essential nutrients for the life of a cell is sugar.

Sugar, in the form of maltose and glucose, is also an essential ingredient in beer. Bacteria living in draught beer and brewing systems are dependent on sugar for healthy metabolism and ATP production. Glucose, specifically, is the precursor molecule for the production of ATP, therefore, when glucose levels are high, ATP production is optimized and cells grow and reproduce at a healthy sustainable rate. If nutrient availability is depleted, cells will slow their production of new ATP molecules and conserve existing ATP.

In a study of 21 different bacterial species belonging to the genus Enterococcus, nutrient-deprived cells that were unable to produce ATP due to starvation were placed in a 1% (wt/vol) glucose liquid growth agar to stimulate ATP production. The result was an immediate 5 to 30-fold increase in both intracellular and extracellular ATP within the first hour (Hironaka, Glucose Triggers ATP Secretion from Bacteria in a Growth-Phase-Dependent Manner, Applied and Environmental Microbiology, 2013).

The effect nutrient availability has on cellular processes and ATP level is quite significant, and must be taken into consideration when interpreting results of an ATP test with regard to bacterial population and sanitation.

Oxygen

Another effect that environmental conditions have on bacterial production of ATP is caused by the presence or absence of oxygen. Oxygen, like sugar, is essential to the health of a cell. It is the single determinant of aerobic and anaerobic metabolism. When oxygen is present in the environment, cells perform aerobically. Environmental oxygen is taken up by the cell and utilized in cellular respiration for ATP synthesis. When oxygen is available, cellular respiration occurs at a rate that yields 32 ATP molecules per 1 glucose sugar molecule.

It is standard practice in the brewing and draught beer industries, though, to implement procedures that minimize oxygen levels in beer, therefore, many of the microbes contaminating beer are likely to be undergoing anaerobic metabolism as well. Anaerobic metabolism is stimulated when oxygen levels are low. In beer, bacteria rely on fermentative anaerobic pathways for their survival. Fermentation enables cells to metabolize glucose sugar in the absence of oxygen, but yields only 2 ATP molecules per glucose molecule (Nelson, Principles of Biochemistry, 5th ed., 2008).

Depending on the level of dissolved oxygen in any beer, ATP levels will vary up to a factor of 16 between aerobic and anaerobic metabolism. Such dramatic variations in ATP levels are the effect of dissolved oxygen concentration and biochemical response by bacteria, and are not correlated to bacterial population size.

Biofilms

Biofilms are complex communities of bacteria living in a self-produced matrix that is capable of adhering to both inert and biological surfaces (Van Houdt, Biofilm formation and cell-to-cell signaling in Gram-negative bacteria isolated from a food processing environment, Journal of Applied Microbiology, 2003). Biofilms are a somewhat recent topic of interest to biochemists and microbiologists, as the industrial relevance of bacterial biofilms has grown to be quite significant.

Biofilms display a level of cooperative strategy among bacterial communities that is unobserved in planktonic (free-floating) bacteria. Many species of bacteria are capable of organizing communal defense mechanisms and survival strategies by forming into films. Biofilms are protected by a mucosal or polysaccharide layer that is secreted by the participating cells. This layer not only protects the colony from environmental stress, it also selectively channels chemicals throughout the microbial community to conserve essential biomolecules like ATP while efficiently transporting waste out (Wilking, Liquid transport facilitated by channels in Bacillus subtilis biofilms, National Academy of Sciences, 2012).

Once biofilms are established, they are difficult to remove and poorly detect by ATP alone. In a study performed by the American Association for Laboratory Animal Science, researchers determined the average minimum detection level for E coli to be 1,000,000 cells per milliliter, and stated that “pure gram-negative bacteria are detected very weakly” by ATP alone (Turner, Efficacy and Limitations of an ATP-Based Monitoring System, Journal of the American Association of Laboratory Animal Science, 2010).

Biofilm development among bacterial species such as E. coli is stimulated as a survival mechanism when population density escalates and nutrients become scarce. Biofilms enable large bacterial populations to persist under sub-optimal living conditions by conserving nutrients, slowing their metabolism, and constructing a protective barrier between the cells and their environment.

ATP is not released from biofilms at a significant rate and therefore should not be used to measure bacterial levels if biofilms are present. In addition, biofilms form when bacterial population size is at its peak, and will render false negative results when serious contamination may in fact be present.

Suggested Methods for Measuring Bacterial Contamination in Beer

The most effective methods for determining sanitary quality involve visualization of actual bacterial cells within a test sample of beer. This is accomplished by placing samples on solid growth media composed of sugar and other essential nutrients, and allowing bacterial colonies to grow. Each cell present in the original sample will grow into a visible colony on the media. Contamination can then be determined based on the number of CFUs (colony forming units) that grow.

This method produces a very accurate measurement of bacterial contamination, which is described in practical terms as a ratio of cells per unit volume. By producing results directly from the physical presence of living bacterial cells, the researcher eliminates the potential for instrumental error and limitations that may be incurred by using electronic test equipment.

The quantitative sensitivity of culture plate tests may also be adjusted by producing serial dilutions of the original sample or altering the volume of sample plated. A very large sample size may be tested to detect minor contamination when cell counts are very low (ie. below the detectable limit of an electronic ATP tester). If contamination is more serious, the visualization and quantification of dense bacterial populations is improved by simply diluting the original sample.

By accurately determining cell count, brewery and draught beer technicians can precisely gauge the effectiveness of their sanitation procedures. Maximum contaminant levels (MCLs) for bacteria should be set as quality control parameters to direct sanitation protocol. By implementing routine culture plate analyses, brewery laboratories and draught beer technicians can ensure proper product quality and the health and safety of their customers.

Beer Line Cleaning Chemicals – A Breakdown

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There are three distinct classes of cleaning chemicals (not just for beer lines): ions, detergents, and enzymes. Each is unique in their chemical structure, rendering them suitable for specific purposes. The major factors to consider when choosing a cleaning solution are the chemical nature of the residue that is being cleaned and the specificity of the cleaning chemical for that particular residue.

For the application of draught beer line cleaning, sugars and proteins are the major residues to be considered. Both of these chemicals exhibit varying degrees of polarity, meaning that they are molecules that carry both negative and positive charges; some are stronger than others, but all are charged nonetheless. Fats and oils, on the other hand, are nonpolar and carry no charge. Fats and oils are found in very minute concentrations in beer, whereas sugars and proteins make up the bulk of the body, flavor, and color of a beer.

Ionic Solutions

Ionic solutions include acids and bases, and are collectively called “electrolytes.” The term “caustic” is frequently used to refer to a basic solution. Ions are the smallest molecules capable of performing big cleaning tasks. Their small size is advantageous because it enables the ion to maximize contact in even the smallest pores and pockets within a contaminated beer line.

Acids utilize the incredibly strong positive charge of protons (Hydrogen ions) to disrupt the bonds and structures of other charged compounds such as proteins, sugars, and even minerals, thus denaturing them and subsequently removing them from a tap system during flushing and rinsing of the system.

The molecular mass of an ionized Hydrogen atom (H+) is 1 atomic mass unit (amu). This is literally the weight of a single proton. Bases, or caustic chemicals, work under the same chemical principle as acids, but they are negatively charged due to the addition of one oxygen atom per hydroxide (OH-) molecule. The oxygen naturally carries a strong negative charge that will disrupt other charged molecules, degrade them, and subsequently remove them from a tap system. Hydroxide molecules are slightly larger, having a mass of 17 amu, but are still very effective at penetrating molecular residues in beer lines, considering sugar and protein masses range from 180 amu to over 1,000,000 amu.

Because ions are so small and their reactivity is non-discriminatory toward polar compounds, acids and bases are capable of breaking down nearly any sugar and protein residue regardless of the size and structure of its chemical constituents.

Detergents

Detergents (aka soaps, surfactants) are designed to attack both polar and nonpolar residues. In chemistry, this unique characteristic of reactivity is called “amphiphilic” – soluble in both water and oil.

Detergents are unique and very useful for certain applications. They can be mixed with water, and the solution may be used to remove sugar, protein, mineral, oil, fat, and grease residues. Detergents’ non-specificity for residues makes them a versatile cleaning compound, and they are generally very good at degreasing and removing fats and oils. Contrary to our application of draught beer line cleaning though, nonpolar fats and oils only occur in trace amounts in beer and have a low tendency to adhere and remain in beer lines.

It is true that hop oils are extracted during the brewing process for their bittering and aromatic attributes, and hops are probably the greatest contributor of oils to any beer. Grain (barley) produces a negligible amount of oil. Of course all plants produce oils – olive oil, corn oil, sunflower oil, peanut oil – but have you ever heard of barley oil? (It actually does exist and is very healthy for you as an antioxidant and source of vitamin E).

Detergents work by forming micelles in water. A micelle is an assembly of surfactant molecules which form a ball-like structure with the polar portions of the molecules on the outside in contact with water (also polar) and the nonpolar ends sequestered on the inside of the ball away from exposure to water. This enables the fatty (nonpolar) ends of the surfactant molecules to disperse throughout a water-based solution and react with other fats and oils. Micelles range in size and are generally far greater in mass than ions. Micelle sizes in terms of amu are in the 100s to 1,000s. This renders them less capable of penetrating dense residues and cleaning porous surfaces such as vinyl.

Enzymes

Enzymes are by far the largest molecules used for cleaning, ranging from about 50,000 amu to well over 100,000 amu. They are also exquisitely specific in their reactivity with other molecules. Textbooks commonly describe enzymatic reactions as a “lock and key” fit. For each enzymatic reaction there is a specific reactant substrate that will fit the active site of a single enzyme type. It is the sole duty of each enzyme type to process a specific reaction involving only the substrate molecule(s) that fit its active site.

The benefit of using enzymes is that they function with extreme precision and work at an incredibly fast rate. This is ideal when a single known molecule is being targeted for destruction. The obvious disadvantage of enzyme-based cleaning solutions for draught beer lines is that there is a wide range of contaminants present, many of which are unknown. Sugar residues must be targeted using enzymes that specifically break down glucose, fructose, lactose, maltose, maltotriose, dextrins, starch, and any potential cross-linking between these sugars. In addition, enzymes that break the numerous peptide bonds within different proteins must also be present.

Last, enzymes that break apart cell walls of invading microbes and digest their by-products must also be present in the cleaning solution. Any chemical contaminant present that has not been degraded by the presence of a specific enzyme will essentially remain untouched. This is how enzyme specificity becomes a serious disadvantage when applied to draught beer line cleaning. It is inconceivable the number of different chemical compounds present in draught beer lines that need to be targeted for destruction and removed during cleaning. Although enzymes may be the fastest and hardest working of all cleaning compounds, they are impractical when tackling the array of known and unknown chemical contaminants that are present in beer lines.

Furthermore, enzymes only perform optimally under specific physical conditions. Temperature and pH are factors that limit enzyme activity. For proper enzyme function, both must be maintained exactly within the enzyme’s functional range, otherwise the enzyme will remain inactive or be denatured.

The preferred cleaning chemicals throughout the draught beer industry are acids and bases. They are cheap, easy to use, very powerful at low concentrations (2-3%), and rinse completely from a tap system due to their high solubility in water. Electrolytes have the longest standing reputation as an effective line cleaning chemical, as their use for this application began in the 1930s. Electrolytes are isolated naturally from the environment as mineral salts Sodium Hydroxide (NaOH), Potassium Hydroxide (KOH), Phosphoric acid (H3PO4) and Nitric acid (HNO3).

Cleveland Beer Line Cleaning uses only acid/base chemistry when cleaning beer lines. We have tested other chemicals and have found them to be effective, but none as dependable as the good old-fashioned electrolyte.

How Beer Line Cleaning Can Increase Draught Beer Sales

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Draught beer line cleaning is performed for two principal reasons:

  1. To achieve proper sanitation, and
  2. to ensure product quality.

Maintaining a clean draught beer system is essential for preserving the integrity and character of each beer. The most common reason customers choose draught beer over bottled is for the freshness.

For a draught beer establishment to earn customer loyalty, it must meet the expectations of its audience. Clientele who are passionate about their beers will keep coming back if service conditions are right. The most important of those conditions is, of course, draught beer quality through proper sanitation.

There are a number of indicators of poor sanitation; and most customers, either consciously or subconsciously, will identify these factors and build an opinion of an establishment based upon them. Obvious indicators include off-flavors, stale aromas, and a lack of foamy head which results from poor tap system sanitation.

The conscientious consumer pays great attention to product quality details, and this practice flourishes within the draught beer and craft beer communities. There is a simple way to earn the respect, loyalty, and repeat business of this vast market of consumers: Provide consistent draught beer quality through proper tap system maintenance and sanitation.

5 Ways to Ensure Beer Line Cleanliness

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1.) Use Fresh Food-Grade Materials

Whether your establishment is utilizing an older draught beer system or if you are shopping for a brand new tap system, using fresh food-grade materials is paramount in ensuring proper sanitation and draught beer quality. Today’s standards in tap system materials are stainless steel and polyethylene plastics. If you are purchasing a new system, be sure that all metal fittings, faucets, and couplers are made of food-grade 304 stainless steel. Older systems will commonly have brass or nickel parts which can easily and affordably be replaced with stainless. On large “long-draw” tap systems, the “trunk lines,” which make up the majority of the system (from the cooler to the faucets), should be manufactured from polyethylene tubing and enclosed in a glycol-chilled insulated packing.

2.) Replace Vinyl Beer Lines

A smaller portion of the system, referred to as the “jumper lines”, will be made of vinyl flex tubing, which connects the trunk to the keg couplers inside of the cooler. Carbon dioxide and nitrogen beer gas lines will often be made of vinyl too. Vinyl is utilized for this application because of its flexibility and resistance to kinking; but vinyl is not considered a food-grade material and these lines should be replaced once a year. Vinyl, unlike polyethylene, has a highly porous surface that will harbor sugar, protein, and microbial deposits that can permanently infect a draught system; therefore, it is best to simply replace these lines on an annual basis.

3.) Routine Caustic Beer Line Cleanings Every Two Weeks

Routine caustic beer line cleanings performed every two weeks by a qualified technician will greatly reduce the risk of microbial infection that may result in beer spoilage and the transmission of food-borne illnesses caused by pathogenic bacteria, mold, and yeast. Caustic solutions of either sodium hydroxide (NaOH) or potassium hydroxide (KOH) destroy sugar and protein residues that build up on the interior of beer lines, and remove microorganisms that reside and feed on these nutrient residues. These solutions should be used at a pH of 12-13. All beer must be purged from the system.

The lines should then be filled with caustic solution, given at least 10 minutes to soak, then all cleaning solution must be removed and the lines rinsed with fresh tap water. The rinse water should be run until its pH matches that of the fresh tap water (6.5-8.5) to ensure all caustic solution has been removed.

4.) Quarterly Acid Cleanings

In addition to bi-weekly caustic cleanings, quarterly (every 3 months) acid cleanings must also be performed to remove mineral deposits. Excess mineral buildup will create a rough interior on polyethylene beer lines, thus negating its anti-microbial effects and rendering it useless for food and beverage applications. To avoid mineral buildup in a tap system, be sure that acid cleanings are performed under the same criteria as caustic cleanings, but with a cleaning solution of either hydrochloric acid (HCl) or peroxyacetic acid (C2H4O3) at a pH of 2-3.

5.) Visually Inspect System Components Daily

Bar staff should visually inspect and hand-clean tap system components every day, and beer faucets should be cleaned every shift. Faucets will accumulate visible sugar and protein residues inside and out, and must be sprayed with an organic solvent such as isopropyl alcohol (rubbing alcohol) to remove them. Faucet brushes are available for cleaning the inside of faucets. Keg couplers should also be checked regularly. When visible residue buildup occurs, these residues should be removed using a toothbrush. Tough residues can be soaked in alcohol or dish detergent to break and remove these sticky protein and sugar films.

By following these simple guidelines, any bar or restaurant can be assured that they are serving draught beer at its highest quality and keeping microbial contamination to a minimum. Be sure to discuss these procedures with your draught beer line cleaner to make sure you are receiving adequate service, and educate bar staff as to the importance of daily in-house tap system cleaning regimens.

Why Draught Beer Line Cleaning is Essential to Your Business

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Tap system neglect is more common than most bar patrons realize. Many bar and restaurant owners are not aware of the importance of regular line cleaning and assume they can go longer than is recommended between routine cleanings. As a result, draught beer systems often fall into disrepair, and the owners wonder why so few people are ordering draught beer at their establishment.

Tap system neglect will quickly result in sanitation problems that distinctly affect draught beer quality and cause severe functional issues. Within only a couple weeks after cleaning a tap system, beer lines, faucets, couplers, and foam detectors accumulate noticeable amounts of solid beer residue, or “beer scale.” These residues harbor bacteria, mold, and yeast, and cause moving parts to stick together and quickly malfunction. Routine cleaning (once every two weeks) will prevent these microorganisms from permanently infecting the system, while ensuring precise, dependable function of the entire tap system.

A poorly maintained tap system can fail any number of ways. Faucet, coupler, and foam detector valves collect sticky residues that prevent them from fully opening and closing, thus resulting in leakage. If the system is leaking beer, this leakage point also provides an entry point for microbial infection that will cause beer spoilage and undesirable souring.

Faucets will also “freeze up” as a result of dried sugar residue that essentially “glues” the internal parts of the faucet together.

Slow drip tray drainage is another common problem. If drains are not flushed daily with sanitizer they will fail, resulting in backup and overflow during high volume service. The backup is caused by an accumulation of sugar residue inside the drain tube, which also grows films of mold, yeast, and bacteria, as well as attract fruit flies.

These are just a few examples of why it is important to maintain the sanitary quality of a draught beer system. Routine cleanings performed by an experienced draught beer technician will prevent sanitation problems and alleviate most functional issues.

Need help with your tap system? Contact us today: 216.533.7936.

How You Can Tell if You’re Drinking from a Dirty Beer Line

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Beer-Scale-2-resized-for-page

We’ve all been there before. You sit down at your favorite bar, order a draught beer, and take the first sip. Only something doesn’t taste quite right. It tastes . . . dirty. Or flat. Or simply horrible. But what does that mean?

First, some of the characteristic indicators of a “dirty” beer line are the same for “dirty” glassware. These indicators are:

  1. Quick loss of head retention
  2. Lack of legs forming and remaining on the inside of the beer glass
  3. Seemingly flat beer due to rapid loss of carbon dioxide gas

All of these factors are related, but they can be the result two unrelated causes—a dirty beer line or dirty glassware. So let’s clarify the difference in terms of “dirty.”

Defining a Dirty Beer Line

The State of Ohio describes a “dirty” beer line as one that has not been kept in compliance with Ohio Administrative Code 4301:1-1-28: Beer and wine: cleaning and sterilizing dispensing apparatus. Although this code goes into no detail about how lines should be cleaned, what methods and chemicals should be used, or what the actual risks to the consumer are if beer lines are not kept to standard, it does state that line cleaning must be performed “not less than once every two weeks.” Therefore, by Ohio law, a “dirty” beer line is one that has not been cleaned by a registered line cleaner in over 14 days. How would you know this? Simply ask to see a bar’s line cleaning log. By law, all bars must maintain a log of their line cleaning, which will be initialed and dated by an Ohio registered line cleaner every time line cleaning is performed.

So how is “dirty” different from beer line to beer glass? A dirty beer line will have sugar and protein residue built up inside. These residues may break off when agitated by the flow of beer, resulting in chunks or flakes in the dispensed beer. This is an ugly surprise to the beer drinker, and quite embarrassing for the bartender and bar owner. Even worse, these pieces of beer solids harbor films of bacteria, mold, and yeast that will quickly spoil the beer once colonies are established inside the line. Even if beer flakes are not dispensed into the glass, be assured that residues do exist in the lines of unkept tap systems, and microbial biofilms harbored by these residues will taint the flavor of draught beer, leaving a sour or dry, cardboard-like taste in the beer, along with a loss of malty sweetness. It is mainly a variety of acids that are detected as off-flavors when sipping a beer that has been spoiled by a “dirty” beer line. These acids also break up the foamy head of a beer, wash those sticky beer legs from the inside of the glass, and expedite the release of CO2 from a once sparkly beer. If you think you’re detecting any of these off-flavors, or if you make any of these visual observations, then you’re probably drinking from a dirty beer line.  

Defining a Dirty Beer Glass

It is important to note that these same visual observations may also be made if clean beer is dispensed into a “dirty” glass. The flavor quality and sanitation of the beer will NOT be effected, so be careful before drawing any conclusions as to the cleanliness of the tap system. A “dirty” beer glass is any glassware that does not permit full contact of beer and glass. Beer sugars and proteins bind to glass resulting in full head retention and beautiful scaffolding of legs on the glass’s interior throughout the life of a pint, no matter how long or short that time may be.

So what could possibly get in the way of foamy head structure and leg formation on a glass’s interior? Well, anything else that sticks to glass. Sanitizers today, such as iodine, are designed to do just that in order to form a sanitary barrier between the glass’s surface and any potential airborne pathogens. This is great in terms of preventing the spread of foodborne illness; and this modern theory and methodology has been applied to all sectors of the food and beverage industry. Plates and silverware receive the same type of sanitary treatment, but the quality and presentation of food is unaffected by this. Rather it’s draught beer service that falls victim to modern sanitation methods.

If you suspect that sanitizer residue is killing the head on your beer, then ask the bartender to re-use your glass. Normally, a good first coat of beer on the inside of your glass will wash away sanitizer residue (consuming iodine will not hurt you) while laying a foundation for excellent head retention on your second, third, fourth . . . or fifth beer. If you notice improved head retention the second time around, then sanitizer was the culprit. Not a “dirty” beer line. This is more common than you may realize.

The second form of a “dirty” beer glass is one that is truly dirty. If it was washed with dirty water it will have an oily or greasy residue coating its surface, which repels water-based solutions like beer. This commonly results when bars do not change their wash-and-rinse water out frequently enough. This is also very common. Watch for a bartender’s or bar back’s attention to detail when running glasses through wash and rinse sinks, and also notice if glasses are being polished with a dry towel after washing and drying. The most important reason to polish is to remove any potential residues that will destroy the integrity of a quality draught beer.

In conclusion, if you order a familiar beer and it tastes and smells right, it is likely that you are drinking from a clean draught system. If you’re in doubt, look for visual indicators. And if you truly believe you’ve been served beer from a dirty beer line, ask to see the bar’s line cleaning log. Check that the date of their last cleaning is within two weeks. The date will be followed by the line cleaner’s initials and his or her 8-digit Ohio registration number.

Have any questions? Contact us today!

What Most Bartenders Don’t Know About Their Own Tap Systems

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Most bartenders and bar owners have a fair working knowledge of how their tap system functions. They’re able to recognize operational defects and malfunctions involving factors like proper refrigeration, carbonation, and beer flow/pour rate.

However, what most bartenders don’t know is the impact poor sanitation has on the performance of a draught beer system.

“Closing the Cut” on Your Beer Lines

Beer is actually very dense with nutrients like various sugars and proteins, and there are dozens of species of airborne bacteria and mold that are constantly on the hunt for nutrient sources. When airborne microorganisms contact beer faucets (especially dirty ones) they immediately begin to feed on nutrient residues left on and inside the faucet, then begin to reproduce and colonize toward the nutrient source: the draught beer line. Proper faucet maintenance is a key factor in maintaining proper sanitation of a draught beer system. Because the faucet is essentially the “open cut” on a beer line that leaves the entire system susceptible to infection, proper faucet cleaning has a significant impact on the amount of bacteria and mold that enter draught beer lines.

While most of these microbes are harmless (i.e. non-pathogenic), they ALL consume the sugars and proteins contained in beer, thus affecting the body and overall malt character of a beer. Byproducts of their digestive processes are then released into the beer. These byproducts include acids that will sour a beer and decrease head retention, and mercaptans which are sulfur-based compounds that make a beer taste skunky. Many of these bacteria and mold will also release gases as a byproduct of their own fermentation, which can affect the perceived carbonation of a beer.

Proper attention to sanitary details is by far the most overlooked step in draught beer maintenance by bar staff. Simple sanitary methods, such as regular hand washing and continual cleaning around faucets and beer towers, greatly reduces the number of airborne microorganisms present. A 50% solution of rubbing alcohol (isopropyl alcohol) is a cheap and effective antibacterial solution for cleaning food grade surfaces without affecting the flavor of the food (or beer) being served. And regular cleaning of beer faucets, towers, and drip trays ensures that the levels of bacteria and mold in a tap system are kept to a minimum.

Have a question? Contact us today >