Copyright, Jeff Stanley, 1999
Part of the ultimate guide to draught dispense!!! (click here)
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.
Some packaged beer is referred to
as draft beer in a bottle because it is cold filtered prior to packaging
rather than pasteurized at very high temperatures. High temperatures will
kill the flavor of the beer. Keg beer is almost never pasteurized. Beer
that has not been pasteurized must be stored cold and goes out of date
much more quickly than packaged beer (usually 45 days after the keg is
filled).
Brewers, distributors, and retailers
all take great care and spend a lot of money to keep kegs cold and get
the product to the consumer as quickly as is possible. The end result is
much higher quality, brewery fresh beer. Draft beer is a product that most
people do not have at home and can only be enjoyed when going out. It is
also much cheaper per serving giving you the option to deliver better value
to your customers.
Keg Specifications for U.S. 1/2
Barrel
Height of Keg -------------------------23.3
Inches
Diameter of Keg ---------------------16.0
- 17.0 Inches
Contents in Ounces ----------------1984.0
Ounces
Contents in Gallons -----------------15.5
Gallons
Contents in Liters --------------------58.7
Liters
Full Keg Weight ----------------------160.5
Pounds
Empty Keg Weight ------------------29.7
Pounds
Beer Weight ---------------------------130.8
Pounds
12 oz. Case Equivalent ------------6.8
Cases
12 oz Servings -----------------------165
16 oz. servings -----------------------124
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.
If the system is not designed properly
using all of the needed components it will waste beer and your bartenders
time by producing excessive foam. A draft system is like a car. There are
many parts on a car that are not needed to make it run smoothly. But I
wouldn't buy a car that did not have a gas gauge no matter how well it
ran. If you are cutting costs on a draft system make sure they are cosmetic.
Do not remove options that make the system work better.
All draft systems must have preventative
maintenance service at least every two weeks. At the very least the lines
should be cleaned and the faucet should be removed and cleaned. The lines
cleaner should also check the temperature of the beer during every cleaning.
This will help weed out many problems before they become beer wasters.
The bar staff must be properly trained
to pour beer, clean and store glassware, and to recognize and report pouring
problems. If the beer is pouring too fast, or is foamy, it cannot be fixed
if it is not reported. Customers will let the server or bartender know
if the beer does not taste right. Never pour from a system that is not
working properly. You will waste beer and loose customers.
Glassware should be "beer clean".
Beer glasses that are not cleaned using a detergent designed for beer glasses
will cause both pouring and off taste problems. Petroleum based detergents
used to clean other glassware and restaurant dishes leave a film on the
glass that will cause co2 to break out of the beer. This results in foamy,
flat tasting beer with little or no head retention. A beer served with
no head on it does not look very appealing and is less profitable. Glassware
chillers can also cause problems. Placing glassware in a cooler before
it is allowed to dry after washing will not allow the sanitiser used in
the final rinse to evaporate. This can give your beer an off taste. Freezing
beer glasses should never be done for several reasons. Moisture will condensate
on the inside of the glass when it is removed from the freezer even if
it is put away dry. This will water down the beer. This also creates a
layer of ice inside of the glass that will cause a lot of foam and waste
driving up the beer cost. Most beers were intended to be served between
38 and 50 degrees. Serving the beer too cold will numb the customer's palate
and remove much of the beer's flavor. It is easy to spot a glass that is
not beer clean. Bubbles in the beer will cling to the inside of the glass
and there will be large bubbles in the head. Beer served in a beer clean
glass will have no bubbles clinging to the inside of the glass and have
a tight head with small bubbles.
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.
When you are using CO2 to dispense
beer the beer is sensitive to picking up too much gas (over carbonation),
and also loosing gas (going flat). Whatever gas you are using, it always
comes into contact with the beer in the keg. The gas entering the keg pushes
down on the beer forcing it up a tube and out into the draft system. When
using CO2 there is very little room for error when deciding how much pressure
is needed in the keg. If the temperature of the beer raises 2 degrees,
one more pound of pressure is needed. If the temperature of the beer drops
2 degrees, the pressure in the keg needs to be reduced by one pound. Different
brands of beer also need different amounts of pressure. For example at
36 degrees, Coors needs 15psi, Budweiser needs 12psi, Killians Lager needs
13psi, and Bass Ale needs 9psi. If the pressure is more than 2psi out of
calibration the carbonation level of the beer will change causing off taste,
pouring problems, or both. You should never adjust the beer's guage pressure
to control the flow rate of the beer. The flow rate is controled by adjusting
the length of the beer line.
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.
The pockets of gas collect right above
the keg and directly behind the faucet, therefore when you open the faucet
you will get a shot of foam, about 4 ounces of clear beer, followed by
another shot of foam. After which the beer will pour clear until the tap
is at rest for 10 minutes or so, allowing the gas pockets to build up again.
Remember that as the temperature of the beer increases, it will require
more pressure so these same symptoms will occur if the cooler or beer is
more than 4 degrees higher than what the pressure was set for. This is
why it is important to keep the beer at a constant temperature. Whether
you are using a keg box or a walk in cooler it is important to keep the
door closed so that the keg temperature does not fluctuate. If you are
using a keg box it is not wise to store garnishes, tomato juice, or liquor
bottles in the cooler that would require you to open the door frequently.
Gas will also break out of the beer behind the faucet if the dispense tower
is not cooled properly. There should be some sort of way set up to force
cool air into the tower. If the tower is not cooled properly it can also
cause the section of line in the tower to build up a lot of yeast growth.
No matter how often you have your beer lines cleaned this build up due
to warm lines will cause problems with off taste product.
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. 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.
