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Draft Beer Technology1. Retailers Guide to Long Draw Draft Beer Systems2. Retailers Guide to Draft Beer Dispensing (Under 15 ft)
Retailers Guide to Long Draw Draft Beer Systems WHAT IS DRAFT Draft beer today usually refers to
beer that is packaged in some sort of large container (5 gallons or more).
The old English word draft (spelled draught) meant "to pull" because cask
conditioned ale was dispensed with a hand pump called a beer engine.
Keg Specifications for U.S. 1/2
Barrel DRAFT SYSTEMS In the not so distant past most all
draft beer was stored under the bar in a large keg cooler. In these simple
draft systems beer travels through a short line, about six-foot long, that
runs up an air-cooled three-inch tube to a faucet. This is always the
prefered way to dispense beer and works well if you sell only one or two
brands of beer, allowing room behind your bar to store all of your kegs.
Unfortunately if you have six different brands on tap and a back up for
each, twelve kegs behind the bar tends to get in the way. Wheeling a
160-pound keg from the back cooler through a busy kitchen and restaurant
at 7:30 on a Friday night isn't much better. The only solution is to run
the beer lines from a remote location to the bar. This is referred to as a
closed remote draft system, usually a glycol system.
GLYCOL DRAFT SYSTEMS Draft beer must be kept less than 42
degrees from the tap all the way to the faucet. If the beer is not kept
cold all the way to the faucet the quality of the beer will suffer
greatly. Glycol draft systems allow you to keep the beer cold even if the
lines are very long. AVOIDING PROBLEMS
Glycol systems work perfectly and
waste very little beer if they are designed, installed, maintained, and
used properly. Unfortunately most glycol systems fall short in one of
these four areas. USING CO2 TO DISPENSE BEER The gas system is a very important
part of any draft beer system. When a draft system has very long lines it
can mean the difference between a perfect system and one that you regret
purchasing. The gas system can easily effect both the taste of the beer
and how easy (or difficult) your draft system is to pour from. All beers
have some CO2 gas dissolved in them. American lagers have a lot, many
micros and imports have very little. The dissolved gas level of the beer
effects the "nose" of the beer and also the way it feels and tastes in
your mouth. A few beers that are served almost flat (Guinness is one
example) also have nitrogen gas dissolved in them so they will still have
a head on them. USING BLENDED GAS
Beer gas is a very simple and very
effective way to solve most draft problems. If the temperature in your
beer storage area does not remain constant due to high traffic. Or if your
trunk line is not at least as cold as your cooler forcing you to raise
your pressure above ideal, a blend will prevent over carbonation. Beer gas
will many times allow you to run all of your beers at the same pressure
solving problems caused by different beers flowing at different rates.
BEER GAS DON'TS As with anything else there is a wrong way and a right way to use beer gas. If you do not use the proper equipment beer gas can damage the beer and also be very expensive. PRE-MIXED VS ON SITE BLENDING
Blending Gases On Site
Some really cheap blenders such as the one pictured above will work even if they are out of one of the gasses. For example, if your nitrogen bottle is empty these blenders will dispense all CO2 causing severe over carbonation. Cheap blenders are also easy to adjust on site. This creates problems with the wrong people making adjustments that will cause damage to the beer. Once the correct blend is selected and the system is set up no further adjustment is necessary. Some draft parts vendors also offer blenders that mix the CO2 with compressed air to save money on nitrogen. Compressed air will make your beer smell and taste bad in a very short period of time. I cannot emphasize this enough; AIR COMPRESSORS WILL RUIN YOUR BEER AND CHASE AWAY YOUR CUSTOMERS. A 240 cubic foot bottle of nitrogen costs between $15 and $30 and will dispense about 80 kegs. I recommend using the McDantim Trumix-100 gas blender (or Trumix-200 if you sell a nitrogenated beer like Guinness). Many draft equipment suppliers sell it as a private label product. It is very accurate under a wide range of flow demands, has no moving parts to wear out, will not operate if one of the gas supplies has run out, and is tamper proof. The blender from Johnson Enterprises pictured below is a McDantim blender set up to produce two blends. One side is 55% co2 and 45% Nitrogen. This is for the ordinary beers being dispensed at 25 psi. The other side is 25% co2 and 75% nitrogen for Guinness. FLOW OF BEER (F.O.B.) STOPS
There is very little to say about these. They simply shut off the beer flow at the keg when it is empty preventing the lines from draining. This will save the as much as one gallon of beer you would otherwise waste trying to pack the lines every time you change a keg. PUMPS Beer pumps solve most of the same
problems as blended gas. Beer pumps apply mechanical pressure to the beer
in the trunk line instead of using the pressure in the line coming from
the keg. This eliminates problems caused by beer in the trunk line being
warmer than the beer in the cooler, which results in either over
carbonation or beer going flat in the lines. They also prevent beers set
at different amounts of pressure from flowing at different rates. Pumps
allow you to avoid these problems without buying any gas other than CO2,
which is much cheaper over time. Retailers Guide to Draft Beer Dispensing (Under 15 ft)WHAT IS DRAFT Draft beer today usually refers to beer that is
packaged in some sort of large container (5 gallons or more). The old
English word draft (spelled draught) meant "to pull" because cask
conditioned ale was dispensed with a hand pump called a beer engine. Keg Specifications for U.S. 1/2 Barrel
AVOIDING PROBLEMS
Draft systems work perfectly and waste very little
beer if they are designed, installed, maintained, and used properly.
Unfortunately most glycol systems fall short in one of these four areas.
USING CO2 TO DISPENSE BEER The gas system is a very important part of any draft
beer system. The gas system can easily effect both the taste of the beer
and how easy (or difficult) your draft system is to pour from. All beers
have some CO2 gas dissolved in them. American lagers have a lot, many
micros and imports have very little. The dissolved gas level of the beer
effects the "nose" of the beer and also the way it feels and tastes in
your mouth. A few beers that are served almost flat (Guinness is one
example) also have nitrogen gas dissolved in them so they will have
special head characteristics. Pouring problems result when beer goes flat while in
the lines or a keg is exposed to too much pressure for too long. These
problems can be cured by having enough secondary regulators to run each
beer at it's ideal gauge pressure and being careful to store the beer at
an even temperature. Low Pressure If your beer is going flat while in the lines it is caused by the pressure being set too low. It will be obvious to you because the beer line will collect pockets of CO2 gas. These pockets of gas will be worse the longer you go
between uses of the tap. They will also be worse when the keg has a lot of
beer in it because as the gas breaks out of the beer, it will eventually
become flat enough that the problem will stop. You will usually experience
this problem during at least first half of the keg. High Pressure
Mild over carbonation symptoms usually closely resemble those caused by beer going flat in the lines. The difference is that they will appear when the keg is nearly empty (the last 1/3 or so). Remember that as the temperature of the beer drops, it needs less pressure to maintain the proper carbonation level. Therefore, you may see these problems if your beer is stored on line at temperatures less than 35 degrees. The ideal temperature range for keg storage is 35 to 40 degrees.
CO2 The first thing you need to understand is carbonation. CO2 is a gas that dissolves easily into water (and beer). The amount of gas dissolved into beer is measured in volumes. If one liter of beer is carbonated to 2.5 volumes, then there are 2.5 liters of CO2 gas dissolved into the beer.
CO2 gas has little or no detectable flavor, but as gas comes out of the solution (bubbles and foam), it does release aromas and flavor characteristics in the beer, affecting the flavor. When a brewer produces a beer, he takes care to control the carbonation level in a way to bring out the flavors and aroma, to effect the flavor in a controlled way. Usually, beers with a strong bitterness and aroma are not carbonated as highly as beers with less flavor and aroma. For example, Bass Ale is carbonated to 2.2 volumes of CO2. Bass has a fruity sweet flavor and a decent amount of bitterness and aroma from hops. A relatively low CO2 level of 2.2 volumes compliments it perfectly. It makes the beer feel smooth in the mouth and releases just the right amount of the complex hop and malt aroma. On the other hand, Coors Light has 2.8 volumes of dissolved CO2 (from Golden, CO brewery). Coors light is not very malty or "hoppy", therefore it has more CO2 to help bring out the "qualities" it does have. Pressure Pressure, measured in pounds per square inch, is defined as the force at which the CO2 molecules in the head space of the keg push on the beer. As the pressure increases, the gas hits the beer with more force and dissolves into the beer more easily. As the pressure decreases, the gas does not dissolve into the beer as easily and gas can come out of the beer. High pressure increases the carbonation level, low pressure reduces the carbonation level. The right amount of pressure in a keg will maintain the right carbonation level. Most breweries or distributors can give you suggested pressure settings for the beers they sell. If you make your own beer use a carbonation chart to determine the proper pressure. Temperature and CO2 Balance The temperature of the beer effects the amount of pressure needed in the keg to control the carbonation level. As temperature increases, CO2 bubbles expand and will come out of the beer. As temperature drops, CO2 dissolves more easily into the beer. For example, at 38 degrees F, Coors Light needs 15 psi to maintain its CO2 level. At 40 deg F it needs 16 psi. At 36 deg F it needs 14 psi. Generally, a two degree
increase in temperature requires a one pound increase in pressure. A two
degree decrease in temperature requires a one pound decrease in pressure.
Illustration "B" represents too little CO2 pressure. Gas breaks out of the beer into the head space of the keg and in the lines. Pockets of gas will accumulate in the lines creating pouring problems as well as flat tasting beer. Illustration "C" represents too much CO2 pressure, more CO2 is dissolving into the beer than is breaking out. The carbonation level of the beer is increasing. Pouring problems and "buzzy" tasting beer will result when the keg is low and dispenses the over carbonated beer. Over carbonated is often perceived as tasting extra bitter. Pouring Problems and CO2 Pouring problems result when beer goes flat while in the lines or a keg is exposed to too much pressure for too long. These problems can be cured by having enough secondary regulators to run each beer at it's ideal gauge pressure and being careful to store the beer at an even temperature. Low Pressure If your beer is going flat while in the lines it is caused by the pressure being set too low. It will be obvious to you because the beer line will collect pockets of CO2 gas.
These pockets of gas will be
worse the longer you go between uses of the tap. They will also be worse
when the keg has a lot of beer in it because as the gas breaks out of the
beer, it will eventually become flat enough that the problem will stop.
You will usually experience this problem during at least first half of the
keg. High Pressure If your keg is exposed to too much pressure or is on line for too long you will experience problems caused by over carbonation. Over carbonation symptoms appear when the carbonation level of the beer increases because the pressure is set too high. Mild over carbonation symptoms usually
closely resemble those caused by beer going flat in the lines. The
difference is that they will appear when the keg is nearly empty (the last
1/3 or so). Remember that as the temperature of the beer drops, it needs
less pressure to maintain the proper carbonation level. Because of this,
you may see these problems if your beer is stored on line at temperatures
less than 35 degrees F. The ideal temperature range for keg storage is 35
to 40 degrees F. Beer in direct contact with the gas picks up the CO2 first. It takes a lot of time for the gas to absorb deeply into the beer so over carbonation usually is most evident at the end of the keg. If you tap a fresh keg and it is very foamy, there is a 99.9% chance that the problem is not over carbonation. Maintaining Quality Five things must be done to maintain the quality of the beer being dispensed. The first is to prevent oxygen from entering the keg. If your keg is going to last more than two days you must use CO2 to pressurize the keg. Hand pumps are not OK for anything other than one night long parties. 'Nuf said. Second, the beer must be consumed in a reasonable amount of time. Draft beer is generally only good for 45 days after it is filled. Don't buy a keg to save money if you cannot consume it in a reasonable amount of time, you will be doing yourself a favor to only buy as much beer as you can consume in a week, two at the most. 1/4 bbls and 1/6 bbls can be a good solution to this. Third, the beer must be kept cold. The 45 day expiration date usually assumes the beer will be kept below 40 deg F. Higher temperatures greatly accelerate spoilage. The entire system must be kept cold, from the keg to the faucet. A good rule is to treat beer the same way you would treat milk. Fourth, the system should be cleaned after every keg or every two weeks, which ever is longer. Line cleaning kits for home systems are available and usually cost under $50 - $80. Fifth, you must keep the glassware in very good condition. If you do not use cleaner designed for bar glasses then beer glasses should be cleaned especially well and rinsed very well. Always allow them to air dry, do not towel dry. If (god forbid) you freeze your glasses, don't put them in the freezer 'til they're dry. Freezing your glassware will destroy the beer's flavor and cause a lot of foam. Most people cannot follow these steps properly, someone invented cans and bottles for this reason. Pressure Regulators There are many brands of pressure regulators. The prices vary greatly, all are basically the same. There are a few features that are important to look for. There should be secondary a pressure gauge that reads, at most, 60 psi. Gauges that read higher than this are difficult to adjust accurately. Many regulators also have a high pressure gauge to read the amount of gas in the bottle. The high pressure gauge should be used in systems that do not have a back up bottle of CO2 so there will be enough warning to get a new bottle. Always replace the bottle once the pressure on the secondary gauge begins to drop and nears the red area of the high pressure gauge. When the primary pressure gets low in the bottle the secondary pressure will begin to drop. You will not lose very much CO2 if the bottle is changed before it is empty, and you will prevent pouring problems that waste beer. Beer and CO2 Line What brand to use? Any vinyl line that is brewery approved sold by a draught parts distributor is usually ok, but there are things to look for. Always get clear line for gas and beer. This will allow you to see if the line is clean and aids troubleshooting (I will cover this later). It is possible for the thomas (check, one way) valve in the tap to fail and let beer into the gas line, clear line will let you see this and fix it. Of course, clear beer line lets you see yeast and beer stone build up in the line plus it will let you actually see the gas breaking out of the beer when the pressure is set too low. Air line is usually 5/16" id and beer line is always 3/16" id (in a short system). Using 1/4" id or larger for beer line will not restrict your system properly and prevent the proper pressure adjustment. Ask for the restriction value (pressure drop) of the line when you purchase it. Faucets There are three basic types of beer faucets. First,
the regular ordinary faucet you will see in every bar on the planet;
second, the little plastic one that hooks directly to the line; and third
the euro type that is most common in dispensing Guinness. Shanks The shank is the threaded metal pipe that attaches to the beer line at one end and the faucet at the other. There are two things to consider when buying a shank. First is the length. If you are using an old fridge, the shank needs to extend into the fridge about 6" to help keep it and the faucet cold. The other thing to consider is the inside diameter. Always use a 1/4" id shank. This reduces the force the beer hits the back of the faucet with and reduces foam. Some more highly carbonated beers will not pour through a 3/16 shank without a LOT of foam. All beers pour better through a 1/4" shank. 'Nuf said. Line Length and Restriction The system restriction controls the flow rate of the beer from the faucet. Most of the restriction comes from the beer line. There is also restriction from gravity and from some draught equipment but it has little effect (less than 1 foot of length) on most short systems. (If your system has a lot of vertical rise or fall, gravity has .5 lb/ft of restriction) Using equal pressure and restriction gives a flow rate of 1 gal/min. This is usually too fast. The best way to determine the right length is to take the ideal pressure, add 5, divide by the line's restriction value per foot. If the beer pours too slow for you, shorten the line 6" at a time. Example:
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