Draught Beer Quality Manual - 2nd Edition
Draught Beer Quality Manual - 2nd Edition
Draught Beer Quality Manual - 2nd Edition
draught beer
quality manual
Prepared by the
Technical Committee of
the Brewers Association
SECOND EDITION
preface
t he Draught Beer Quality working group was
formed in March 2007 under the direction of
the Brewers Association Technical Committee.
Our overriding mission was to improve the quality of
draught beer dispensed to our customers. We seek
our mission
To improve the quality of draught beer
for all beer drinkers.
to preserve the great flavor and aroma of beer creat-
ed by the brewer, and to deliver it to the consumer at our goal
retail. Great beer must be handled conscientiously
To make our website information available
to arrive in the glass in perfect condition.
to as many beverage industry members
and consumers as possible, and work to-
Distributors, wholesalers, retailers, or draught instal-
ward being the definitive draught quality
lation teams may install a draught system. But once in
resource for the USA.
place, each system commonly pours a wide range of
brewers’ and suppliers’ products. We have sought to www.draughtquality.org
bring the industry together to agree upon guidelines
that present everyone’s beer in an optimal condition.
When handled properly from brewery to bar to glass, This second version of the Draught Beer Quality Man-
draught beer delivers what many consider to be the ual includes several updates, and we will continue to
freshest, most flavorful beer available to the customer. refine it in the future. Our goal is to provide useful and
But the job does not end once the keg is tapped and current information for all industry members, manufac-
the beer begins to flow. Good beer quality depends turers, distributors, retailers, and consumers.
on proper alignment of the dispense variables and
consistent housekeeping practices. As one industry This manual and excerpts from it are available at www.
insider quipped, “Even the Mona Lisa would look draughtquality.org. This website is in wiki form, and
terrible in a museum with lousy lighting.” also contains far more information than this manual,
in the form of downloadable forms and links to techni-
The draught quality group focused on these and other cal and supplier resources. For example, the website
areas to develop a clear and well-researched resource contains beer line cleaning logs you can download,
of best practices for draught beer. Of course, individ- print, and post on your walk-in coolers to encourage
ual brewers may have additional quality requirements routine cleaning every 14 days. We encourage all in-
or recommendations for various brands beyond these dustry members and affiliated groups to link to the
commonly agreed upon guidelines. website. n
Special thanks are extended to Ken Grossman, President of Sierra Nevada Brewing Co. As the 2008 Chair of the
Brewers Association Technical Committee, Ken galvanized the creation of this manual through a collaborative effort
with the brewing community, and we appreciate the time and dedication he and his colleagues put forth to bring
this project to fruition.
Special thanks to Avery Brewing Company, Boulder, Colorado. Thanks also to Block 15 Brewing Company, Corvallis,
Oregon and Real Ale Brewing Company, Blanco, Texas for providing images.
The Brewers Association wishes to thank the United States Department of Agriculture and the Colorado State
Department of Agriculture for their support and funding of this project. State funds for this project were matched
with federal funds under the Federal-State Marketing Improvement Program of the Agricultural Marketing Service,
U.S. Department of Agriculture.
SECOND EDITION © Brewers Association, 2011. Chapter heading photos ©2011, Shutterstock, LLC, Jupiter Images, and Getty Images
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Beer .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
temporary systems
fixtures the beer passes through during its journey to
the bar.
Picnic Tap
Cooling Jockey Box
The cooling system should hold beer at a constant
temperature from keg to glass. Any increase in beer direct draw
temperature between the cooler and the faucet
Keg Box
can lead to dispense problems such as foaming. In
Walk-in Cooler
a simple direct-draw system, a refrigerated cabinet
long draw
maintains the temperature of the keg and provides
cooling to the beer as it travels the short distance
to the faucet. Many long-draw systems use a walk-in Air-Cooled
refrigerator to cool the kegs, plus chilled glycol that Glycol-Cooled
circulates in tubes next to the beer lines all the way to Beer Pump
the faucet, to ensure that the beer stays cold all the Mixed Gas Dispense
essential draught
system components
Keg Valve
Kegs are pressurized vessels and can be dangerous if
mishandled. Nearly all modern kegs use some form of
Sankey valve and stem. There are two main types of San-
key valves and corresponding keg necks: “drop-in,” and
threaded. From a user standpoint, the valves function
identically; from above, they appear nearly indistinguish-
able to the untrained eye. Drop-in Sankey valves are
held in place by a lock ring or circlip. The lock ring and
valve should never be removed in the field. Very rarely a
lock ring can fail, possibly loosening the valve, creating a
potentially dangerous situation. Threaded Sankey valves
screw into the neck of the keg. Very rarely a threaded
valve can inadvertently loosen or become unseated when
disengaging a coupler, creating a potentially dangerous
situation. Keg valves should never be removed in the
field. Kegs should only be serviced by trained personnel.
Vinyl Barrier
Polyethylene
Beer Line
Between coupler and faucet, beer travels through
beer line selected to fit the needs of the specific
draught application. Options range from vinyl to spe-
cialized barrier tubing and even stainless steel.
installation onto the faucet lever; in many cases, to pressurize a keg as the oxygen in the air gener-
however, the tap marker may not be aligned properly ates stale flavors in beer within just a few hours. All
when seated fully on the lever. For this reason, gas used for beer dispense should meet the speci-
nearly all faucets are also fitted with a lever collar fications of the International Society of Beverage
or handle jacket on the lever (see images above). Technologists or the Compressed Gas Association
These allow the tap marker to be aligned properly, (See Appendix A).
as well as installed securely. Install the tap marker on
the faucet lever and check to make sure it’s aligned Retailers may purchase beverage grade gas in cyl-
appropriately. If not, unscrew the marker just enough inders that will be delivered by the gas vendor and
to align it correctly, then back the lever collar up swapped out when empty. Such cylinders are filled,
under the marker, and tighten the tap marker snugly maintained, and inspected by the vendor. High vol-
onto the lever collar or handle jacket. ume users may purchase a bulk gas vessel known as
a Dewar that will be filled on location from a bulk
Gas Source gas truck. Bulk tanks can provide CO2 for both soda
Draught systems depend on gas pressure to push and beer.
beer from the keg to the faucet. To achieve this, kegs
should be pressurized with carbon dioxide, or a car- CO2 tanks contain both liquid and gas phases. The
bon dioxide and nitrogen mix. tank pressure is dependent on ambient temperature
and—regardless of tank fill level—will vary from 600
Gas used for draught dispense should be “beverage – 1200 psi until empty. For safety reasons, CO2 tanks
grade.” Gas selection and purity affect the freshness should never be located inside the refrigerator or
and quality of the beer served through the draught walk-in cooler. A gas filter may be installed to help
system. Remember: The gas you use fills the keg as reduce the likelihood that any contaminants in the
the beer drains. Thus, off-flavors or impurities in the gas reach the beer (be sure to follow manufacturer
gas quickly migrate to the beer to spoil its freshness recommendations for filter maintenance intervals; see
and flavor. Compressed air should never be used page 32 for more information).
Secondary Regulators
Regulator
Braided Vinyl
Gas Line and often two pressure gauges that help in setting
Gas line should be selected to withstand the pres- pressures and monitoring gas levels. Valves and an
sures expected in the draught system. Vinyl tubing adjustment screw control the actual flow of gas from
between gas line and beer line, colored vinyl is used to the gas source, namely a portable bottle or bulk
for CO2 supply lines in some systems. Clear vinyl tank. This regulator typically contains two gauges:
may also be used as it aids in troubleshooting by one high-pressure showing the tank or supply pres-
allowing you to see if beer has escaped the coupler sure, and a second low- or regulated pressure gauge
and entered the gas line due to a faulty or missing showing what is being delivered to the keg. Some
Thomas valve. And because vinyl gas line will fail simpler regulators may contain only one gauge
at lower pressures than braided vinyl or poly, it can displaying the delivered pressure, making it more
also serve an important safety function in the event difficult to predict when the bottle is getting low on
of secondary regulator failure by blowing off before CO2. Some suppliers provide jockey box regulators
a keg becomes overpressurized. preset with no gauges, since these are easily dam-
aged in transit.
runs. Braided vinyl is commonly used in soft drink an integrated “O” ring seal in the face of the regu-
lines for both beverage and gas. lator fitting, or a fiber or Teflon flat washer. These
parts need to be replaced occasionally to prevent
temporary draught
dispense
equipment and
configurations for direct
draw draught systems
r etailers use direct-draw systems in situations
where the kegs can be kept refrigerated in
very close proximity to the dispense point or
faucet. In some cases, the beer sits in a cooler below
the counter at the bar. In other cases, the keg cooler
• A walk-in cooler with beer dispense directly
through the wall from the keg to the faucet.
Shanks
Most draught systems firmly mount the faucet to
either a tower or a wall, making it a stable point for
beer dispense. A threaded shank with securing nuts
creates the solid connection to the supporting tower
or wall. The faucet then connects to one side of the
shank and beer line connects to the other side by
either an attached nipple or a tail piece connected
with the usual washer and nut. Today, shanks with
1/4” and 5/16” bore diameters are most commonly
available and recommended in the U.S., along with
3/16” bore diameter shanks, which are less common.
The once-common practice of drilling out a 3/16”
Shadow Box bore diameter shank to one of the larger sizes is
In some direct-draw applications inside a walk-in not recommended as the resulting unfinished brass
cooler, it may be necessary to cut a section out of shank bore surface will be detrimental to draught
the cooler wall where the shanks are placed. The wall beer quality, and because drilling will likely dam-
is then recessed in a “shadow box” to minimize the age shanks and glycol chilled towers beyond repair,
shank length and keep foaming to a minimum. meaning expensive replacement will be necessary. n
equipment and
configurations for
long-draw draught
systems
t he most complex draught systems fall into the long-
draw category. Designed to deliver beer to bars
well away from the keg cooler, these systems usually
employ equipment not seen in temporary and direct-draw
setups. From around 1990 to 2010, the average long draw
Beer
While exceptions exist, most long-draw systems still
push beer from kegs. Beer exits the keg through a
coupler and usually enters a vinyl beer line just as we
have seen with temporary and direct-draw systems.
system had doubled in complexity from roughly five fau- But here the vinyl doesn’t last long. It typically goes
cets to more than 10 faucets. Today it’s not uncommon to about six feet before connecting to a wall bracket
find very complex draught beer systems at retail with doz- that serves as a transition to specialized barrier tub-
ens of faucets, dispensing up to many dozens of beer ing. Designed for minimum resistance and superior
brands. While long-draw systems offer designers the cleanliness, barrier tubing should carry beer most of
option to put beer far from the bar, providing keg handling the distance from keg to faucet in long-draw systems.
or layout flexibility, the distances they cover come with But barrier tubing isn’t the end of the journey; most
increased opportunities for problems and increased costs draught towers use stainless steel tubing to carry the
for equipment, cooling, and beer waste. As with all systems, beer to the faucet. In addition, many systems install
it’s important to minimize line length and diameter where some length of narrow-gauge vinyl tubing called
possible to minimize beer loss and facilitate cleaning. “choker” between the end of the barrier tubing and
the stainless steel tubing of the draught tower, to pro-
Let’s consider the three draught dispense sub-systems vide a way to accurately balance the system. In the
of beer, gas, and cooling to see what long-draw systems end, however, the beer flows through a faucet just as
include. we saw with the direct-draw systems.
You may also find Foam On Beer (FOB) detectors on Many older long-draw systems installed single-wall
the beer lines of many long-draw systems. Located in polyethylene tubing. This relatively porous material
the cooler at or near the wall bracket, these devices allows oxygen ingress, carbon dioxide to escape, and
fill with dispense gas when beer from a keg runs out, makes cleaning difficult, resulting in stale, flat, and
thereby shutting off flow to the main beer line. This potentially tainted beer in the lines. Today, you may
prevents beer loss by keeping the main beer line full find blue and red polyethylene tubing carrying glycol
of pressurized beer while the keg is changed. The from and to your glycol power pack; this is the only rec-
jumper line between the keg and FOB is then purged ommended use for polyethylene tubing in long-draw
and normal beer service can resume. See page 27 for systems. Long-draw systems with vinyl or poly lines
more information about FOBs. (typical of much older systems) should be repacked
with fresh beer each day due to the detrimental effects
Components: of oxidation; the beer drained during this process can
be used for cooking. This expense alone can signifi-
Barrier Tubing cantly decrease the payback time when replacing an
Barrier tubing has a “glass-smooth” lining that inhibits old long-draw system with barrier tubing.
beer or mineral stone deposits and microbial growth to
maintain beer freshness. Its properties make it the only Vinyl tubing should only be used as jumpers between
industry-approved beer line for long-draw systems. keg couplers and long-draw barrier tubing trunks,
and as restriction tubing between barrier tubing
Barrier tubing may be purchased by itself in various trunks and faucet shanks. Vinyl and polyethylene
diameters, but most suppliers sell it in prepared bun- tubing should never be used in long-draw bundles.
dles (called bundle or trunk housing) with beer lines
and glycol coolant lines wrapped inside an insulating Choker Line
cover. These bundles vary by the number of beer lines Choker line, also known as restriction tubing, is a sec-
they carry with popular sizes matching the number of tion of 3/16” ID vinyl tubing of variable length installed
faucets commonly found on tap towers. at the tower end of a long-draw system. The purpose is
Wall Brackets
Wall brackets join tubing together in a long-draw cold
box. The wall bracket gives a solid connecting spot Another version of an FOB that performs the same
for jumper lines from the keg. Tubing is connected function is available as an existing feature on a keg
with a washer, nut, tail piece, and clamp combina- coupler, as shown above. This variety does not have
tion. (Most of these installed in the past were made of a float but smaller moving parts that shut off the flow
plated brass, and should be inspected for wear and of beer when gas is present. It is not as easily dis-
replaced with stainless steel.) assembled or cleaned as the wall-mounted varieties
Gas Blenders
Gas blenders mix pure tank CO2 and pure tank nitro-
gen to specified ratios. Blenders can be ordered to
specific ratios and provide one, two, or even three
blends. Three product blenders will usually be set to
dispense beers at 2.7 volumes of CO2, 2.5 volumes of
Single Mix Blender CO2, and nitrogenated beers. Existing one and two
mix blenders can sometimes be upgraded to two and
three blends; be sure to check with your supplier. Rec-
ommended features for a gas blender include:
• Output mix is preset by the manufacturer and is
not adjustable onsite.
• Blender shuts down when either gas supply runs out,
preventing damage from running on only one gas.
• Blender produces two or three blends so that both
“nitro” and regularly carbonated beers can be
served. The blends for regularly carbonated beers
can adequately serve products with a reasonable
range of CO2 volumes (e.g. 2.2-2.8 volumes of CO2).
Nitrogen Generators
Three Mix Blender
Nitrogen generators extract nitrogen from the
atmosphere. Air is supplied by either a remote or
Cooling
As with direct-draw systems, kegs reside in a walk-
in cooler held at 34° to 38°F. But to keep beer cold
throughout its journey from keg to faucet requires
additional cooling components that surround the
beer lines themselves. We find two common designs:
In-Line Gas Leak
air-cooled and glycol-cooled.
Detector.
draught operations
a matter of balance
Barrier 1/4” ID 0.30 lbs/ft 1/3 oz/ft for each foot the beer travels. We have mentioned
Barrier 5/16” ID 0.10 lbs/ft 1/2 oz/ft beer lines made from vinyl, barrier tubing, and even
Barrier 3/8” ID 0.06 lbs/ft 3/4 oz/ft stainless steel. Each type and diameter has a differ-
Stainless 1/4” OD 1.20 lbs/ft 1/6 oz/ft ent resistance (stated as “restriction”) to beer flow
Stainless 5/16” OD 0.30 lbs/ft 1/3 oz/ft as shown in the chart. (Note: This chart is provided
Stainless 3/8” OD 0.12 lbs/ft 1/2 oz/ft as an example only. Please consult your equipment
Temp
34 °F 2.5 2.7 2.9
Units of Carbonation 38 °F 2.3 2.5* 2.7
In the U.S. and some other countries, the industry mea- 42 °F 2.1 2.3 2.5
sures beer carbonation in units of “volumes of CO2”. A
typical value might be 2.5 volumes of CO2, meaning lit-
CO2 pressure
erally that 2.5 keg-volumes of uncompressed CO2 have
9 psi 11 psi 13 psi
been dissolved into one keg of beer. Carbonation lev- 34 °F 2.5 2.7 2.9
Temp
els in typical beers run from 2.2 to 2.8 volumes of CO2, 38 °F 2.3 2.5* 2.7
but values can range from as little as 1.2 to as high as 42 °F 2.1 2.3 2.5
4.0 in specialty beers. * Pressures rounded for purposes of illustration.
Do not use these charts for system adjustment.
Temp
estimate grams per liter. So, a beer with 2.5 volumes of
38 °F 2.3 2.5* 2.7
CO2 would contain about 5 grams per liter of CO2. For
42 °F 2.1 2.3 2.5
more information on this calculation, see Appendix B.
Beer in a keg at 38°F needs a pressure of 11 psi to
Now that we understand the concepts of beer temper- maintain 2.5 volumes of CO2 as the beer is served.
ature, applied pressure, resistance, and carbonation, As long as the temperature and pressure remain con-
let’s look at how they interact in a draught system. stant, the beer maintains the same carbonation level.
level of the beer. Because beer carbonation can vary The key to maintaining a keg’s carbonation relies
with the temperature of your cooler and the pressure on fine-tuning four elements:
applied to the keg, you must take care to maintain
steady values suited to your system and beers. 1. CO2 percentage
2. Applied pressure
Pressure gauges used on draught systems measure 3. Keg temperature
in pounds-per-square-inch gauge, or “psig“. This is 4. A particular beer’s carbonation level
the difference between the pressure in the keg and
atmospheric pressure (14.7 psi at sea level). When When all the elements are in balance, the beer will
dispensing beer at elevation, the carbonation level of stay properly carbonated. For many systems using a
the beer doesn’t change but the pressure displayed single gas blend for regularly carbonated beers, the
on the gauge will read low, by approximately 1 psi per appropriate blend will be 70% CO2. For this reason,
every 2,000 feet. So a keg dispensed at 10,000 feet 70% CO2 is the default setting for most gas blenders
would need to have the gauge pressure increased by when no other is specified. To see the mathematical
approximately 5 psig above the calculated dispense relationship between these factors as well as how to
pressure at sea level. See pages 16-17 for more details figure exact gas blends for various carbonation levels,
on correcting for elevation. see Appendix C.
You can determine ideal gauge pressure for pure CO2 A common issue in many draught systems is that many
from the chart shown in the table above and in Appen- beers with different levels of carbonation are being
dix B. If you do not know the carbonation level in the poured on the same system. With the other three
beer, you can estimate it using the procedure found in previously mentioned elements remaining the same,
Appendix B. many beers can become flat. The solution lies in mak-
ing adjustments to either of the two elements we can
has historically been difficult if not impossible. Gas draught system will pour clear-flowing beer
blending panels usually have only one CO2-rich blend at the rate of 1 gallon per minute, or approx-
available, with dual blend panels typically accommo- imately 2 ounces per second.
Most nitrogenated beers are poured through system have a fixed resistance value, draught sys-
a special faucet that, because of its added re- tem designers select from a variety of choices to
striction, requires the beer to be dispensed create systems with a target total resistance value.
between 30 – 40 psi. Even though the solu- For instance, a 20-ft. run of 1/4” internal diameter
bility of nitrogen is relatively low, this high vinyl beer line gives a total resistance of 17 psi while
dispense pressure does provide for some 5/16” barrier tubing of the same length only gener-
increased absorption of nitrogen, creating ates 2 pounds of resistance. If our target resistance
a creamy head when dispensed through the value is 20 psi, the 1/4” vinyl system would need 1
nitro faucet. foot of 3/16” choker line added at the tower end to
achieve the total system target resistance, whereas
the 5/16” barrier system would need 6 feet of 3/16”
pressure variance between different beers is kept at choker added at the tower end to reach the same
or below 5 psi. target (see chart of beer tubing restriction values
on page 36).
System Balance
So far we’ve seen what happens to a beer’s carbon- Thus, any draught system can be designed to operate
ation in the keg as the result of applied pressure under a range of applied pressure values. Whenever
and temperature. But of course beer must travel possible, the operating pressure will be set to main-
from the keg to the glass, and along the way it tain the carbonation of the beer being served.
encounters the fourth measure we introduced,
namely resistance. The beer line and changes in Unfortunately, in some systems this doesn’t work.
elevation impart resistance to the flow of beer from Consider the resistance created by long beer lines
the keg to the faucet. and climbs of two or more floors. Even with the low-
est resistance components, the applied pressures for
The pressure applied to the keg overcomes this resis- these systems often exceed that needed to maintain
tance and drives the beer through the system and to beer carbonation. These systems must use mixed gas
the customer’s glass. To achieve proper flow and beer or pneumatic beer pumps to overcome the problem.
quality, the pressure applied to the keg must equal
the total resistance of the draught system. Mixed Gas
As we have seen, beer readily absorbs carbon diox-
We have already seen that the pressure applied to ide. Any change in CO2 pressure on a beer results
the keg needs to be matched to the carbonation in a change in the carbonation of the beer. Nitro-
level of the beer. This means we have two differ- gen is different. Beer does not absorb nitrogen
ent factors to consider when deciding the pressure gas to any significant degree. This means we can
to apply to a keg. This creates a problem when apply nitrogen pressure to beer without changing
the resistance of the system calls for more—or the properties of the beer. Thus, in high resistance
less—pressure than is needed to maintain the car- draught systems, we use a mixture of CO2 and N2
bonation of the beer. To prevent conflicts, draught to achieve two objectives: 1) maintain proper beer
technicians design system resistance to match the carbonation and 2) overcome the system resistance
pressure applied to the beer. to achieve a proper pour.
This example assumes that the dispense gas blend mixture is already fixed, a vertical lift of 12 feet, and
a beer trunk line total run of 120 feet. Find the operating pressure of the system, and then determine
appropriate tubing size for the trunks, and length of restriction tubing.
• Beer Conditions
-- Beer temperature: 35°F
-- Beer carbonation: 2.6 volumes of CO2 per volume of beer
-- Dispense gas: 70% CO2 /30% nitrogen blend from Appendix C,
a = ((b+14.7)/c) – 14.7
where a is the pressure, b is the ideal pressure of straight CO2 for this situation (in this case, 10.7
psi, see chart in Appendix B), c is the proportion of CO2 in the blended gas
a = ((10.7+14.7)/0.70) – 14.7
a = (25.4/0.70) – 14.7
a = 36.3 – 14.7
a = 21.6, or round to 22 psi
-- Gas pressure needed to maintain carbonation = 22 psig
• Static Pressure
-- Vertical lift = 12 feet (Tap 12 feet above the center of the keg)
-- Static resistance from gravity = 12 ft. x 0.5 pounds/foot = 6.0 pounds
• Balance
-- Applied dispense gas pressure of 22 psi must be balanced by total system resistance
-- Since static resistance equals 6 pounds, the system will need a total of 16 pounds of dynamic
resistance
-- Restriction = 22 - 6 = 16 pounds
120 ft. of 5/16” barrier @ 0.1 pounds per foot = 12 pounds
1.3 ft. 3/16” vinyl choker = 4 pounds
12 + 4 = 16 pounds
Carbonation (Volumes CO2) 2.3 2.4 2.5 2.6 2.7 2.8 2.9
psig Applied CO2 9.2 10.3 11.3 12.4 13.5 14.5 15.6
3/16” Vinyl beer line length 3’3” 3’5” 3’9” 4’2” 4’6” 4’10” 5’7”
preparation to pour
Cold Storage and Proper Chilling of To help ensure that your kegs are properly chilled
Kegs before Serving before serving, Chart 1 provides a guide to the
To ensure fresh flavor and ease of dispense, approximate time needed to properly chill a keg to
draught beer should remain at or slightly below 38°F from a given starting temperature. Note that
38°F throughout distribution, warehousing, and even kegs that “feel cold” (e.g., 44°F) may need to
delivery. Brewers and distributors use refrigerated chill overnight in order to ensure proper dispense.
storage for draught beer. In warm climates or long
routes, they may also use insulating blankets or Chart 2 shows how quickly a keg will warm up when
refrigerated delivery trucks to minimize tempera- exposed to temperatures above 38°F. From this you
ture increases during shipping. can see that a keg will warm up during delivery or
storage at ambient temperature from 38° to 44°F in
At retail, even a few degrees’ increase above the only four or five hours. But looking back at Chart 1,
ideal maximum of 38°F can create pouring problems, we see that same keg will need to be in the cooler
Start Temp Time to 38° F counts that will “turn” or empty kegs rapidly. The
To achieve the qualities the brewer intended, beer Each approach requires specific techniques and a cer-
must be served following specific conditions and tain degree of discipline. Let’s look at what’s involved
techniques. Let’s review some of the critical condi- with each one.
tions necessary for proper draught dispense.
Manual or Hand Cleaning in the
• Beer stored between 34° - 38ºF. Three-Tub Sink
• Beer served between 38° - 44ºF. 1. Clean sinks and work area prior to starting to
• To accomplish this, the glycol cooling the beer lines remove any chemicals, oils, or grease from other
in a long-draw system should be set to 27º - 32ºF. cleaning activities.
• Balanced draught settings (pressure = resistance).
• Normal flow rate of 2 ounces per second.
Glassware Cleaning
A perfectly poured beer requires a properly cleaned
glass. As a starting point, glassware must be free of
visible soil and marks. A beer-clean glass is also free
of foam-killing residues and lingering aromatics such
as sanitizer.
Helpful hints:
Faucet Hygiene
We recommend quickly rinsing faucets with fresh water
at the close of business each day. Studies have indi-
cated that in retail locations that use this simple step,
system maintenance
and cleaning
Cleaning Guidelines
Many states require regular draught line cleaning, but
Minerals also precipitate from beer, leaving deposits all too often the methods used fall short of what is
in lines and fixtures. needed to actually maintain draught quality. In pre-
paring this manual, our committee polled all sectors
Within days of installing a brand new draught system, of the beer industry and called on our own many
deposits begin to build up on the beer contact sur- decades of cumulative experience to determine
faces. Without proper cleaning, these deposits soon the necessary and sufficient conditions for proper
affect beer flavor and undermine the system’s ability draught maintenance. In this chapter, we recommend
to pour quality beer. and detail the practices that have proven effective in
sustaining draught quality.
draught beer line soil types
Hop resin sticky
Please note that all parts of the recommendations
Grain protein gummy
must be implemented. The proper cleaning solution
Yeast & micro resistant
strength won’t be effective if the temperature is too
Minerals hard
Bio-film homogenous mass cool or there is insufficient contact time with the lines.
The lines themselves will remain vulnerable to rapid
decline if faucets and couplers aren’t hand-cleaned
When undertaken using proper solutions and proce- following the recommended procedures.
dures, line cleaning prevents the buildup of organic
material and mineral deposits while eliminating fla- As a retailer, you may or may not clean your own
vor-changing microbes. Thus, a well-designed and draught lines, but you have a vested interest in mak-
inhibit bacteria and yeast growth, they have little or -- All faucets should be completely disassem-
bled and cleaned.
no cleaning effect on draught hardware and fittings.
-- All keg couplers or tapping devices should
be scrubbed clean.
Line Replacement and Material
-- All FOB-stop devices (a.k.a. beer savers,
• All vinyl jumpers and vinyl direct draw lines should
foam detectors) should be cleaned in line,
be replaced every year.
and cleaning solution vented out of the top.
• All long-draw trunk line should be replaced in the
• Quarterly (every three months)
following instances:
-- Draught beer lines should be de-stoned with
-- When the system is 10 years or older.
an acid line cleaning chemical or a strong
-- When flavor changes are imparted in a beer’s
chelator that is added to or part of the alka-
draught line from an adjacent draught line.
line chemical formulation. (The DBQ working
-- When any line chronically induces flavor
group is working with brewing industry
changes in beer.
researchers to complete further studies on
• Draught lines may need to be replaced after pour- line-cleaning chemistry, including additives
ing root beer, fruit-flavored beers, margaritas, or such as EDTA.)
ciders. Such beverages may permanently contami- -- All FOB-stop devices (a.k.a. beer savers,
nate a draught line and possibly adjacent draught foam detectors) should be completely disas-
lines in the same bundle. Such contamination pre- sembled and hand-detailed (cleaned).
cludes future use of that draught line for beer. -- All couplers should be completely disassem-
• In the case where a coupler’s gas backflow valve bled and detailed.
(Thomas valve) is or ever has been missing, the
gas line may have been compromised and should Cleaning Solutions and Their Usage
be replaced. Caustic-Based Cleaning Chemistry
• Ensure the material used in the manufacture of the • Caustic chemicals remove organic material from
draught beer lines is compatible with the chemicals, the interior of the draught line, hardware, and fit-
dilution rates, and temperatures outlined on the fol- tings. The removal of this buildup prevents growth
lowing pages (also see “Beer Line” in Chapter 1). of beer-spoiling bacteria such as lactobacillus,
pediococcus, and pectinatus.
Detailed Recommendations • Use a caustic cleaner specifically designed for
The following sections detail more specific recom- draught line cleaning that uses either sodium
mendations on draught line cleaning. We begin with hydroxide, potassium hydroxide, or a combina-
the basic issue of tasks and their frequency, then tion of both.
move into the more involved questions of cleaning • Routine use of caustic line-cleaning chemical
draught beer lines. Chlorine is not compatible -- Nitric acid is not compatible with nylon
products, including some commonly used
with some beer line materials, and residual chlo-
draught line tubing, and should not be used
rine can cause flavor changes in draught beer.
for cleaning draught lines.
• Based on brewery and independent lab testing,
• Mix acid line cleaner to the solution strength rec-
we recommend mixing caustic-based line clean-
ommended by the manufacturer.
ing solutions to a working strength of at least 2%
• Mix acid line cleaner with water warmed to a tem-
caustic (as sodium hydroxide). A 3% caustic solu-
perature between 80º -110ºF.
tion is more appropriate for problem systems,
• Acid solution must remain in contact with the
heavily soiled systems, systems with older lines,
draught line for at least:
or for any line that imparts a flavor change to
-- 15 minutes when solution is being recircu-
the beer served from it. Contact your chemical
lated, or
manufacturer to determine how much chemical
-- 20 minutes for static or pressure pot cleaning.
is needed to achieve these recommended con-
centrations.
Water Rinsing
• We recommend the use of portable titration kits
• Always flush draught lines with fresh water before
to confirm the working caustic strength of beer
pumping chemical into the line.
line-cleaning solutions.
• Always flush draught lines with water after using
• Mix caustic solution with water warmed to a tem-
any chemical solution (caustic and acid).
perature between 80º - 110ºF.
• Continue water flushing until:
• Caustic cleaner must remain in contact with the
-- No solid matter appears in the rinse water.
draught line for at least: -- No chemical residue remains in the draught
-- 15 minutes when solution is being recirculated, line.
and
• Confirm chemical removal by testing the solution
-- 20 minutes for static or pressure pot cleaning.
with pH strips or a pH meter.
-- Before beginning the rinse, draw a reference
Acid Chemical sample of tap water and test its pH.
• Acid line cleaner removes inorganic materials -- During rinsing, test the rinse water exiting
such as calcium oxalate (beer stone) and calcium the draught system periodically.
carbonate (water stone) from the interior of the -- When the pH of the rinse water matches that
draught line, hardware, and fittings. of the tap water, the chemical is fully flushed
• Routine use of caustic cleaning solutions with out.
EDTA or other chelating agent additives may • Chemical solution must never be flushed from
reduce calcium oxalate buildup in draught lines draught lines with beer.
troubleshooting
The purpose of this manual is to explain how to main- potentially costly outcomes is key to serving great tast-
tain the brewery-intended flavor of draught beer prod- ing draught beer.
and enjoyable. Draught beer is susceptible to damage that occur due to post-brewery unhygienic conditions
from a host of factors, such as age, heat, and air. But the and the mishandling of draught products. Beer-spoiling
number one factor affecting the quality of draught beer bacteria will ruin a beer’s flavor and aroma, and will in-
flavor and aroma is poor hygiene. Improper cleaning of evitably lead to lost repeat business and potential sales.
beer system lines and components from the coupler in While these microorganisms are not health risks, they
the cooler to the faucet at the bar can lead to significant will cause bacterial infections in draught systems that are
changes in beer flavor, all of them unwelcome. Over often difficult, if not impossible, to completely remove.
time, poor beer line hygiene will inevitably result in loss By following the guidelines outlined in this manual, the
of sales due to customer dissatisfaction, and to replac- occurrence of these off flavors can be prevented. n
The leading cause of acetobactor comes from faucets not being Stainless steel is the best material for
completely disassembled and hand-detailed on a two-week cycle. faucets to prevent bacterial buildup.
Oxidation Papery, Cardboard, N/A. Oxidation Oxidation comes from time, temperature, or direct exposure to oxygen. Monitor brewery-recommended best-
Fruity, Bready, Vinous, in beer is a All beers have an expiration date. This is the date by when a brewery consumed-by-dates and temperature
Vegetal (These are reaction that feels the beer has taken on significant oxidative properties, and that the specifications.
only a few descriptors occurs when a beer no longer represents the brewery-intended flavor.
as oxidation is a very beer is exposed Ensure any kegs in series have been
broad term and different to oxygen This expiration date can easily be shortened with the addition of warm completely emptied (series kegs should be
ingredients will take molecules. temperatures. Draught beer should be kept cold (below 50° F) at all times completely emptied and replaced once per
on different oxidative to maximize its freshness. The longer a beer is kept warm and/or the week).
properties) higher the temperature, the faster the beer will oxidize. If a beer ever rises
above 80° F, for any amount of time, the beer is likely ruined. Never use compressed air in direct contact
with draught beer.
In draught beers, oxidation can happen with the use of an air
compressor. If an air compressor is used to dispense draught beer, Use barrier and stainless steel tubing
oxygen will be forced into the keg, and can oxidize a beer within 24 whenever possible.
hours (Chapter 1).
Porous beer tubing material will allow oxygen to leach through to the
beer after extended pouring delays (Chapter 4).
appendix a
• The values in this table assume sea-level altitude, beer specific gravity of 1.015, and beer alcohol content at 3.8%
abw or 4.8% abv. Values shown are in psig, or gauge pressure.
• It’s important to remember that carbonation is proportional to absolute pressure, not gauge pressure. Atmospher-
ic pressure drops as elevation goes up. Therefore, the gauge pressure needed to achieve proper carbonation at
elevations above sea level must be increased. Add 1 psi for every 2,000 feet above sea level. For example, a retailer
at sea level would use 11.3 psi gauge pressure to maintain 2.5 volumes of CO2 in beer served at 38º F. That same
retailer would need 13.3 psi gauge pressure at 4,000 feet elevation to maintain 2.5 volumes of CO2.
carbonation,
blended gas, gas laws
& partial pressures
Carbonation beer, then all of the pressure on that keg is due to CO2.
In general, the amount of carbonation in beer de- But what if the gas being used is a blend of 75% CO2
pends primarily on the pressure of CO2 applied to the / 25% N2? In this case, Dalton’s Law can help us figure
keg of beer being dispensed, and the temperature of out what’s going on. Dalton’s Law of partial pressures
the beer. In reality, many other factors can also affect says that the total pressure exerted by a gaseous mix-
carbonation levels including blended gas proportion ture is equal to the sum of the partial pressures of each
of CO2, alcohol content, and specific gravity. Knowing individual component in a gas mixture. This means the
a bit about these factors can help you finetune your partial pressure of CO2 is equal to the proportion of
draught dispense system to achieve the perfect pour CO2 in the gas, in this case 75%, times the total abso-
for every brand dispensed. lute pressure of the blended gas, or 34.7 psia (20 psig
+14.7 psi atmospheric pressure = 34.7 psia). In this
Temperature: In general, gas is less soluble in liquid case, the partial pressure of CO2 is:
as the temperature rises. This seems obvious—a nice
cold keg of beer dispenses easily, while that same keg 75% x 34.7 psia = 26.0 psia
of beer dispenses as foam if it gets warm. 26.0 psia – 14.7 psi atmospheric = 11.3 psi gauge.
Proportion of CO2 in blended gas: This is directly re- So, in this example using blended gas, the carbonation
lated to the pressure of the CO2 in the headspace over of the beer will be proportional to 11.3 psi of CO2,
the beer within the keg. Two different gas laws (Dal- NOT 20 psi CO2. It’s important to note this calculation
ton’s Law of Partial Pressures and Henry’s Law) can help must be done in absolute pressure, then converted to
us make sense of what’s going on. This is most easily gauge pressure (if you used gauge pressure of 20 psi
described by example, along with a little math. Con- rather than 34.7 psia, 75% of that value would result
sider a situation in which a keg of beer is dispensed in 15 psi as the partial pressure of CO2 in this scenar-
using gas at 20 psi. If pure CO2 is used to dispense io, which is not correct.) Consulting the carbonation
draught beer system? And, looking at this another way, 14.1 psi.
is there a way to use this math to figure out the ideal
14.1+14.7 28.8
pressure to use, given a certain blend of gas? c= = = .830 or 83% CO2
20+14.7 34.7
As it turns out, there are tools available online to do In this case, a gas blender with more than one blend
both of these tasks with a great degree of accuracy. of mixed gas would be very helpful. You would use
There are also some relatively straightforward calcu- the 77% CO2 to dispense the beers with 2.5 volumes
lations that do the same things very quickly, shown of carbonation, and the 83% blend to dispense the
here. The following equation is very useful for con- beers with 2.7 volumes of carbonation.
a = (b + 14.7)/c – 14.7
a = 28.8/.77 – 14.7
a = 37.4 – 14.7
a = 22.7 psi
notes on serving
cask ale
Cask Ale
Cask ale, sometimes called “cask conditioned beer” means that CO2 is not as soluble in the beer, so it
or “real ale,” is draught beer dispensed and served contains far less carbonation. (See below).
in a traditional method. Cask ale is usually served
at warmer temperatures than regularly carbonated Carbonation
draught beer, and without applied pressure. The re- Because cask ale is handled at warmer temperatures,
sult is a beer with different presentation, flavor, and and since CO2 is less soluble at warmer temperatures,
aroma, wholly unique from the same beer filtered, cask ale contains much lower levels of carbonation
force carbonated, and dispensed with CO2 or mixed than regular draught beer. Cask beer typically contains
gas top pressure. from 0.9-1.2 volumes of CO2, far less than the 2.5 to 2.7
volumes typical of carbonated draught beer.
In this manual, we’ll focus on a few particulars of dis-
pensing cask ale that represent basic knowledge and The carbonation in cask ale arises from natural sec-
best practices. The care and handling of cask ale is an ondary fermentation within the cask, rather than from
art unto itself, sometimes referred to as “cellarman- force carbonation at the brewery. The relatively warm-
ship,” the details of which are well beyond the scope er cellaring temperatures allow this fermentation to
of this manual. Please refer to the online version of occur after the cask leaves the brewery.
this manual for supplier and knowledge links.
Dispensing Cask Ale
Temperature Cask ale is normally dispensed from a cask located
Cask ale is typically conditioned and dispensed at relatively close to the bar, or even on the bar or back
45º-55ºF, unlike the colder 36º-40ºF range for regularly bar. Most modern casks are metal, although a few
carbonated draught beer. This temperature is warm wooden varieties are sometimes still found. Most
enough to allow the beer within the cask to develop casks contain two openings that are filled with wood-
its own natural carbonation. This temperature also en or plastic plugs called shives (for letting gas in)
Tool Tips
• Put safety first and always wear eye protection
• Buy the best tools you can afford, as they will last a lifetime
• Always use the right tool for the job
• Keep your tools clean, sharp, calibrated, and organized
Tooling
70. Drill Bit Set - Cobalt Steel Bits with 135° Points
71. 12 1/4” Drill Bit
72. Hole Saw Extender
73. Hole Saws - Many Sizes
74. Cutting Oil
75. Coring Bits For Stone / Concrete
Acid Cleaner – Although several blends of acid Caustic Potash or KOH or Potassium Hydrox-
cleaners are recommended to assist in beer stone ide - Similar to sodium hydroxide, but offers slightly
and water stone removal, some acids react with sys- different chemical properties in a blended cleaning
tem components. Phosphoric acid-based blends are solution.
the only ones safe on all materials.
CO2 – Carbon dioxide, a natural product of fermenta-
Balance – Ensuring that the applied pressure match- tion and the gas used to push beer in draught beer
es the system requirements so that the beer dispens- systems. CO2 leaks in the gas system are dangerous
es at the optimum rate of about 2 ounces per second because high concentrations of CO2 will displace air
or 1 gallon per minute while maintaining brewery- and cause asphyxiation.
specified carbonation level.
CO2 Volumes – The concentration of CO2 in beer
Barrier Tubing – Plastic tubing with a lining of nylon expressed as volumes of gas at standard conditions
or PET that provides a gas barrier to better protect per volume of beer.
the beer from oxidation.
Coil Box – A cooling system to bring beer to serving
Beer Pump – A mechanical pump that is generally temperature at the point of dispense consisting of a
driven by compressed air or CO2 that can move beer coil of stainless steel immersed in ice water. Often
great distances without changing the dissolved gases. used at picnics or events where normal keg tempera-
ture cannot be maintained.
Beer Stone- Calcium Oxalate – A mineral deposit
that forms slowly on a surface from beer and is very Cold Plate – A cooling system to bring beer to serv-
difficult to remove. ing temperature at the point of dispense consisting of
a stainless steel coil embedded in an aluminum plate
Caustic or Caustic Soda or NaOH – Sodium in contact with the ice. Cooling is the result of melt-
hydroxide – a high pH chemical commonly used in ing the ice rather than just heat transfer, so water must
blending draught line cleaning solutions that will re- be drained away from the cold plate. Often used at
act with organic deposits in the draught beer line. picnics or events where normal keg temperature can-
Very effective, but also very dangerous. Commonly not be maintained.
used in oven cleaners.
Flash Chillers – Mechanical cooling systems to bring NSF – National Sanitation Foundation: An organiza-
beer to serving temperature at the point of dispense. tion that certifies food service equipment for perfor-
Often used with flash-pasteurized kegs that can be mance and cleanability.
stored at room temperature.
Party Pump or Picnic Pump - A hand pump that
FOB – Foam on Beer detector. A device that stops uses compressed air to dispense beer. This type of
the flow of beer when the keg is empty before the pump should only be used when the entire keg will
beer line is filled with foam. be dispensed at one time, because oxygen will dam-
age the beer.
Glycol or Propylene Glycol – A food-grade re-
frigerant that is recirculated through insulated tubing PE – Polyethylene – Stiffer tubing used in older
bundles to maintain beer temperature. refrigerated bundles (this oxygen-permeable mate-
rial contributed to oxidation of the beer remaining
ISBT – International Society of Beverage Technolo- in the lines and is now only recommended for use as
gists, who created a quality standard for CO2 for bev- glycol tubing).
erage use.
Pot – Pressure Pot, Cleaning Pot – A canister for
Jockey Box – A cooler with a coiling coil or cold plate cleaning solution or rinse water that is connected to
and faucets to chill the beer at the point of dispense. a pressure source pushing the solution through the
lines like beer. Does not give sufficient velocity for
John Guest Fittings – A specific brand of quick (mechanical) cleaning, so this should only be used on
connect for stiff plastic tubing. short lines with longer chemical exposure.
Jumper Tubing – The flexible piece of vinyl tubing PSI – Pounds per square inch. A unit of measure of
used between the keg and draught beer system that gas pressure.
should be replaced annually.
PSIG – Pounds per square inch, gauge. A measure Surfactants – Compounds used in blended draught
of gas pressure against the atmospheric pressure, beer line cleaners that lower surface tension to en-
typically seen on gas regulator gauges. Since atmo- hance surface wetting, break the bond between de-
spheric pressure varies with altitude, the gauge pres- posits and the tubing surface, and suspend soils in
sure must be adjusted with altitude. cleaning solution so they can be removed.
PVC – Polyvinyl Chloride – Flexible jumper tubing. Tail Pieces – The connectors that allow a piece of
tubing to be attached to a piece of equipment.
Regulator – A gas control valve that delivers a set
gas pressure regardless of tank pressure. There may Tap – The connector from the draught system to the
be a primary regulator on the gas source and a sec- keg (more properly referred to as a coupler).
ondary regulator at the gas connection for each keg.
Tavern Head – The connector from the draught sys-
Resistance (or System/Component/Line tem to the keg (more properly referred to as a coupler).
Resistance) – A measure of the pressure drop
across a component or over a length of tubing at Tower – The mount on the bar that holds the faucets
the optimum beer flow rate. and is cooled to maintain beer temperature up to the
point of dispense.
Sanitizer – An EPA-registered product that is de-
signed to kill microorganisms. Water Conditioners – A component of a blended
cleaner that is intended to carry away soils.
Sankey – The modern style of keg coupler. It is avail-
able in several versions to fit specific styles of keg Water Stone – Calcium Carbonate – A mineral de-
valves produced in Europe and the U.S. posit that forms from water and can be removed with
acid. n
Sequestrants – Chemicals that hold metal ions in
solution and prevent mineral deposits.
Brewers Association
736 Pearl Street
Boulder, CO 80302
303.447.0816 • 888.822.6273
draughtquality.org
info@brewersassociation.org
Brewers Association
$6.95 U.S. www.BrewersAssociation.org