As with many products, coffee machines were first developed for commercial use and than adapted for home use.  There are two basic types of commercial coffee makers and both use the drip method to brew coffee.  Most people are familiar with the coffee makers used in diners and convenience stores.

Most diners and convenience stores use a drip coffee maker that is similar to the coffee machine you probably have in your home.  These coffee makers generally don’t have to be filled with water, because they have a water source hooked up right into the machine.  They do utilize the coffee baskets, filters and pots seen in home machines.

These commercial coffee machines usually have multiple warming plates.  You can only make one pot of coffee at a time, but you can put a full pot on a second or third warming plate and make another pot.  The disadvantage of this type of coffee machine is that if the coffee sits on the warming plate too long  it can burn.  Some establishments have overcome this problem by putting the fresh coffee in insulated carafes which will keep it hot for hours without burning it.

The other most common type of commercial coffee machine makes 30 or more cups of coffee at a time.

Like the other type of drip machine its has a dedicated water source that feeds directly into the machine.  These machines are fairly large and usually have a stainless steel finish.  They often have a clear glass tube the indicates the coffee level in the machine.  These machines don’t “burn” the coffee because they are sealed units.  This means that the liquid doesn’t evaporate causing the bitter, burned taste that occurs when an unsealed pot sits on a warmer.

The sealed machine usually has a basket and a paper or mesh filter like other drip coffee makers.  It has a spicket  with a lever that allows the coffee to be released as it is needed.  The coffee can be poured into pots or individual cups.  Since it makes large amounts of coffee at one time, it requires less work than the other type of coffee machine.

Catering services usually use large percolators, since commercial drip coffee machines generally require their own water source.  The type which brews separate pots can be filled with water manually if no water hook up is available, but it is not as convenient as a large percolating urn when serving large numbers of people.