is the general term for devices used to dispense beer from a bulk container such as a keg, cask, barrel, or tank. It is also a verb for the act of broaching a keg or barrel of beer so that it can be served.

The classic functions of a tap—broaching and pouring—are separated into two independent pieces of equipment in modern draught systems. At most bars today, consumers see bartenders pull on a tap handle, which connects to a lever-operated valve, allows beer to flow from a spigot into the glass. Although properly called a “faucet,” many refer to this most visible chrome- or brass-colored element of the draught system as the tap.

Hidden away in a cooler, whether just below the bar or hundreds of feet and several floors away, another device, properly called a coupler, attaches to the keg to open its sanitary seal and allow beer to flow from the keg to the bar. Some refer to the coupler as a tap. Indeed, the act of placing the coupler upon the keg and engaging it to allow the flow of beer is commonly referred to as “tapping a keg.” Thus, the modern act of tapping a keg generally involves a coupler rather than a tap. Couplers used to tap kegs are made of stainless steel and the faucets they pair with may also be made of stainless steel or, more commonly, chrome-plated brass.

But modern draught systems, which drive beer from stainless kegs remote from the drinker’s glass, were only invented about 100 years ago. Well into the 20th century, brewers used wooden barrels to transport and serve draught beer both in Europe and in North America. Some breweries continue to use such wooden barrels of various sizes to serve beer, although generally in special or limited situations. Also, stainless-steel casks with a design similar to that of a wood barrel are currently used for cask-conditioned ale served using a traditional tap.

Both wooden barrels and stainless-steel casks for gravity dispensing are made with a small circular opening near the edge of the head, or flat top, and another in the middle of the bowed side of the barrel. During the filling process these openings are plugged with a wooden bung or with specially shaped pieces with the names of shive and keystone. See cask and gravity dispense.

This style of barrel or cask requires a classic tap. In its simplest form, the tap consists of a straight tube with a valve and spigot at the front. The rear end of the tube is generally tapered slightly and the tube itself is drilled with scores of small perforations. When in use, the rear portion is inside the barrel submerged in beer, whereas the front remains outside to allow for beer service. This classic design allows the tap to be used both for broaching and for pouring.

To initiate service, publicans set a barrel on its curved side, rotated so that the plug or bung in the flat top is at the bottom, closest to the floor or serving shelf on which the barrel rests. Once the barrel is secured, they swiftly hammer the tapered rear section of the tap through the wooden bung or keystone and into the barrel so that it snugly fills the open hole. Once inserted, the tap allows beer into its tubular center via the perforations. When the front spigot is opened, beer flows out of the spigot and into a waiting glass.

Early taps were made of wood and today some are made of highly durable plastic, but for much of their history, taps were made from brass for both strength and durability. Although all have a tubular element, many variations on the basic shape and appearance have been adopted for either functional or decorative reasons.

The classic tap design is still used daily in certain limited applications. The pubs operated by German breweries may tap wooden kegs set upon the bar this way. Those who serve traditional cask-conditioned ale in England and the United States commonly use classic taps as well. Ceremonial tappings at festivals and special events often employ traditional barrels and taps. Hammering the tap through the bung or shive with a wooden mallet makes for a dramatic event—especially when accompanied by a frothy spray of beer at the moment of broaching. In Bavaria, it is usually a prominent political figure who is called upon to tap the first cask at a festival—before the assembled press, of course. A poor performer at this weighty public function may have a hard time getting reelected. Call it politics not by the ballot but by the mallet.