Coffee makers used in the GM are normally electric and may be of different types. The automatic twin coffee urn and the automatic coffee maker

and 4-16) are the types used most often in general and private messes.

Figure 4-15.-Automatic twin coffee urn.

Figure 4-16.-Automatic coffee maker.

Operation of the Automatic Twin Coffee Urn

To brew coffee, turn thermostat dial to the BREW position. Observe dial thermometer on front of the urn. When brewing temperature is at the high end of brew zone on dial, the urn is ready to brew coffee.

Place paper filter or muslin leecher bag in brew basket. Place desired amount of coffee in filter (use urn grind coffee in 3-gallon urn and regular grind in larger urns), replace cover, and place brew basket in position over coffee liner. When using muslin bag, be sure bag is soaked with cold water before using, and, if a new bag, be sure to wash out all sizing with warm water. Swing spray arm from the PARK position over brew basket and center spray nozzle over brew basket. Push timer knob. After the timer has completed its cycle, the orange brewing light will go out, showing that the proper amount of water has been sprayed. Within 3 minutes the brew basket with spent coffee grounds should be removed from urn. To do so, swing spray arm back to center PARK position. The spray arm should always be parked in this center position so expansion drippage will go back into tank. Do not leave the brew basket in liner over 5 minutes, if possible. Remove cover and brew basket and then always replace cover over coffee liner. Rinse out muslin leecher bag and store in cold water until ready to use.

Keep the thermostat dial at the HOLD position during all standby periods so that the urn is ready to brew coffee at any time, with no waiting.  Merely turn thermostat to the BREW position so the pilot light lights up during brewing. During shutoff periods, turn thermostat to OFF. After all night or weekend shutoff, a minimum of at least 55 minutes is required to obtain the proper brewing temperature. On twin models, water for tea may be drawn from center faucet. Manual refill is required unless equipped with auto refill.

Care and Cleaning of a Coffee Urn

The procedures used in caring for and cleaning a coffee urn are as follows:

1. Always rinse urn immediately after each use.

2. Add small quantity of hot water, brush sides, and rinse with hot water until it runs clean. Urn is now ready for next batch.

3. At end of each day clean and brush urn several times and then rinse thoroughly with hot water.

4. Remove cleanout cap at end of coffee faucet (or take apart faucets that have no caps) and scrub pipe leading to center of urn. Clean urn gauge glass with brush and urn cleaner. Rinse thoroughly.

5. Scrub the faucet and then rinse it thoroughly with hot water.

6. Place a gallon or more of fresh water in urn until next use.

7. Remove cover and clean. Replace cover and leave partly open.

8. Always remember to empty and rinse the urn with hot water before using again.

NOTE: On automatic urns, use any of the BREW, START, STOP, or RINSE switches to spray scalding hot water into the liner for cleaning and rinsing. On Pour-over urns, draw hot water directly from urn. Make sure urn water tank is kept nearly full and the heat is on.

Destaining a Coffee Urn

The procedures for destaining coffee urns are as follows:

1. Fill urn with destaining compound solution. Fill urn with water 175F. Add destaining compound (stain remover, tableware, in this ratio: 2 tablespoons per 5 gallons of water or as directed by manufacturer).

2. Draw off mixture and repour. Open spigot and draw off 1 gallon; thoroughly remix to allow mixture to come into faucet. Allow solution to stand for 1 hour at 170F to 180F. Stir occasionally.

3. Scrub urn liner and gauge glass. Use long-handled brush to loosen scales.

4. Clean faucet. Take faucet valve apart and clean all components. Soak in hot water until reassembled.

5. Rinse and reassemble faucet valve. Rinse urn liner three or four times carefully with hot water. Repeat until all traces of compound are removed.

Operation and Care of an Automatic Coffee Maker

The automatic coffee maker is designed to brew fresh coffee under strict, sanitary conditions. Each coffee maker is made in units, and each unit may contain four or five burners set in a single or double deck. The coffee maker has the ON/OFF switches and the head control switches on the front.  Glass or metal bowl containers are supplied for the actual brewing of the coffee.

Automatic coffee makers let you pour fresh water into a reservoir at the top of the device to obtain the same amount of hot coffee. In some models, gravity displacement of preheated hot water by cold water is the working rule. In others, water is brought to a boil before brewing a batch of coffee.

In using an automatic coffee maker, there are two phases in making coffee, preheating and brewing. The preheating phase consists of the following steps. Slide the brewing chamber under the spray head and place an empty decanter under it. Then open the top cover and pour two decanters of cold water in the reservoir. Replace cover. Make sure to plug into electric outlet of the correct voltage (specified on the nameplate of device). It should be noted that the two decanters of cold water should be poured in before connecting the plug. Preheat time is usually 18 minutes, and a signal light will turn on when the water reaches the proper brewing temperature.

Brewing good coffee requires skill, technique, and the experience of the skilled foodservice specialist. To properly brew coffee, remove the brewing chamber and place one paper filter in it. Add required amount of the recommended coffee grind. Check to be sure the coffee is evenly leveled before replacing brewing chamber. After the preheating phase, add a decanter of cold water to the reservoir. Coffee will immediately start to brew and flow into the decanter under the brewing chamber. When the flow stops, you are ready to serve.

The simple care of your equipment makes an important contribution to the excellence of your coffee service and efficient use of energy.

All parts of the brewer that come into contact with the coffee and coffee vapor should be kept immaculately clean. Decanters, for example, should be thoroughly cleansed and rinsed free of detergent after each use. Spray heads should be checked regularly for traces of lime or other deposits in or around the holes. It is important to keep them clean.

Paper filters should never be reused as they can pick up odors from other foods. Discard after each brewing process. Be careful where you store them.

Cloth filters should be rinsed after each brew and stored overnight in a vessel of fresh cold water. Replace cloth filters often to ensure good-tasting coffee. A simple sniff test should tell you when it is time to change.

New cloth filters should be cleaned and rinsed in very hot water to remove sizing (starch) and cloth odors. Do not use soap, bleaches, or detergents since they transfer flavors.

If you brew in sealed filter bags with a stainless steel filter screen, rinse out the holding cartridge and screen daily. Once a week soak the screen overnight in a solution of urn cleaner and rinse thoroughly before reusing.