Draft beer - a microbrewer's headache?
Most microbreweries start their packaging operations with only a kegging line. Some refrain from installing a bottling line indefinitely, electing instead to bottle at another brewery. In large part, this is because draft beer is generally more profitable (per unit) for microbrewers.
Draft beer is a carbonated malt beverage that contains alcohol. The main objective is to serve draft beer to the consumer in the same condition in which it leaves the brewery. The surest way to do this is to become familiar with the basics of draft beer.
Draft beer does not improve with age. On the contrary, it tastes the best the day the keg is filled. Every day thereafter it declines in quality. I believe that a keg should only be stored for a maximum of four to five weeks under refrigeration.
Every brewery should provide a filling date or code on the bung, informing wholesalers and retailers how olds the keg is. This allows them to rotate inventory accordingly.
Despite this, problems occur with draft beer, usually during storage. We at the Frankenmuth Brewery, Inc. store our keg beer at 38-40 degrees Fahrenheit (3.3-4.5 degrees Celsius). Before this keg reaches the consumer, however, it will undergo changes in temperature. The internal keg pressure changes as well.
If a keg of beer leaves the brewery at a temperature of 38-40 degrees F., the internal keg pressure is 12 lbs. If the keg was brought across the street to a bar, and tapped right away, the minimum applied pressure would be 15 lbs. Most of the tavern I have visited tap keg beer between 12 and 15 lbs. Now, let's assume that the keg beer leaves the brewery at 38 degrees F. and the driver stops at different retailers before he drops the keg off. For the purposes of our exercise, we'l say that by the time the keg reaches its destination, the temperature is 44 degrees F., the internal keg pressure is 15 lbs. and the minimum applied pressure is 18 lbs. Unfortunately, the retailer taps at 13 lbs. The result is that the applied pressure is not enough, the beer separates into foam and causes wastage. Another example is when there is a lack of pressure, which may flatten the beer in the keg. A third problem occurs when the keg beer is older. The beer more easily absorbs the gas applied and the beer may overcarbonate. Once again, the retailer would only get foam in their tap.
To eliminate these problems, specify that retailers allow a keg to settle for 24 hours before tapping. You should also instruct retailers at which pressure to tap the beer.
Another common problem is often a result of the counter-pressure applied into the keg for drawing tap beer. The best method for applying counter-pressure is through the use of a carbon dioxide ([CO.sub.2]) tank and regulator. Often air is used (although not recommended) or a mixture of air and [CO.sub.2]. If you think about what air contains - water, dust or the musty air from a basement - you see this system is not suitable for tapping beer. Pumping air into beer (for tapping) causes problems; beer gets flat, it becomes cloudy and sometimes infected. Whatever the problem, the end result is the same. The consumer refuses to drink the beer. The result is a loss of profit, which is much higher than the cost of [Co.sub.2].
The next point has to do with beer lines. If these lines are dirty, the beer that passes through them may come out flat or with off tastes. The types of lines used are mostly vinyl or polyethylene lines. The polyethylene lines are easier to clean.
The next step is dispensing the beer. It is necessary to push the beer out of the keg, through beer lines to the beer faucet. This is called lift, and means nothing more than compensating for gravity. Lift is figured by multiplying the distance (in feet) from the center of the keg to the faucet by 1/2 lb.
Checklist for draft beer
1. Temperature of the beer in the keg - This can be taken by loosening the tap and allowing some beer to seep onto the top of the keg. Dip the thermometer into the beer and get an accurate reading. Now you can see if the beer is too warm.
2. The next step is to check the applied pressure. The best way to control it is to have a daily control chart where you write the applied pressure down. If you've never had problems with foaming beer, check the pressure. If it is below or above your normal pressure applied you have resolved one problem.
3. Check the inside of your faucet. A build-up of yeast or bacteria can cause "wild" conditions for beer. Clean the faucet with a brush.
4. Check out the keg itself. Kegs wear out, and must be replaced.
5. Finally, consult with your wholesaler. Most wholesalers have a "draft beer specialist," and they can help you mathematically calculate the needs for an account's draft system.
There is one other problem to discuss. Microorganisms. Most times they are referred to as "bugs" or "germs." There are three varieties: mold, yeast and bacteria. They are not toxic, but they will cause cloudiness and off-flavors in the beer. These microorganisms require food, higher temperatures and oxygen to live and multiply. Beer is an excellent food source, and most breweries are against air pumps for dispensing draft beer. Now you know why.
In conclusion, draft beer should receive careful handling before and after it leaves a brewery. Many microbrewers produce excellent products, but once the beer leaves the brewery there are many intangibles. Nevertheless, if proper attention is given to careful handling, storage and temperature control, the flavor can remain consistent long after the beer leaves the brewery.
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|Title Annotation:||Small-Scale Brewing in America|
|Author:||Scheer, Fred M.|
|Publication:||Modern Brewery Age|
|Date:||May 13, 1991|
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