mug

A white glazed ceramic mug

A mug is a sturdily built type of cup often used for drinking hot beverages, such as coffee, tea, or hot chocolate. Mugs, by definition, have handles and often hold a larger amount of fluid than other types of cup. Usually a mug holds approximately 12 fluid ounces (350 ml) of liquid, double a tea cup. In formal settings a mug is usually not used for serving hot beverages, with a teacup or coffee cup being preferred. Shaving mugs can be used to assist in wet shaving.

Whereas ancient mugs were usually carved in wood or bone or shaped of clay, most modern ones are made of ceramic materials such as earthenware, bone china, porcelain or stoneware. Some are made from strengthened glass, such as Pyrex. Other materials, including plastic, steel and enameled metal are preferred where break resistance is at a premium, such as for campers. Techniques such as silk screen printing or decals are used to apply decorations; these are fired onto the mug to ensure permanence.

History

A mug made on a potter wheel in the Late Neolithic Period (ca. 2500 – 2000 BCE) in Zhengzhou, China

Ancestral Pueblo (Anasazi) mugs from SW Colorado, made between 1000 and 1280 CE. The meaning of the carving in the handles is yet unknown, but it is probably not functional.

The oldest drinking vessels recovered by archaeologists were made of bones, they hardly had a handle and thus are not mugs. The first mugs are related to the Neolithic Stone Age and pottery vessels which were found in China and Japan and date to about 10000 BCE.^[1] The first pottery was shaped by hands and was later facilitated by invention of the potter's wheel (date unknown, between 6,500 and 3000 BCE). It was relatively easy to add a handle to a cup in the process thus producing a mug. For example, a rather advanced, decorated clay mug from 4000–5000 BCE was found in Greece.^[2] The biggest disadvantage of those clay mugs was thick walls unfit for the mouth. The walls were thinned with development of metalworking techniques. Metal mugs were produced from bronze,^[3] silver, gold^[4] and even lead,^[5] starting from roughly 2000 BCE and were hard to use with hot drinks. Wooden mugs were produced probably from the oldest time, but most of them could not be preserved to the present time. The invention of porcelain around 600 CE in China brought a new era of thin-walled mugs suitable both for cold and hot liquids, which we enjoy today.^[6][7]

Shaving mugs and scuttles

Shaving mug

Shaving mug, 1867 patent.^[8]

A shaving scuttle and shaving mug were developed around the 19th century with the first patent for a shaving mug dating to 1867.^[8] As hot water was not common in many households, one way to provide hot lather was to use a scuttle or mug. A traditional scuttle resembles a teapot with a wide spout where hot water is poured in, and this is where it differs from a shaving mug, which has no spout. Both shaving scuttles and mugs usually have a handle, but some have none. Shaving mugs often look like a standard mug, however, some also have a built in brush rest, so the brush does not sit in lather. Modern versions of the scuttle are in limited production, usually by independent potters working in small volumes.^[9]

At the top of the scuttle or mug is a soap holder. Traditionally, it was used with a hard block of shaving soap (rather than soft soap or cream) and therefore had drain holes at the bottom. Later scuttles and mugs do not include the holes, and thus can be used with creams and soft soaps. Some scuttles and mugs have concentric circles on the bottom, which retain some water thus helping to build lather.^[9]

In use, the shaving brush is dunked into the wide spout, allowing it to soak into the water and heat up. The soap is placed in the soap holder. When needed, one can take the brush and brush it against the soap, bringing up a layer of lather; excess water is drained back. This allows conservation of water and soap, whilst retaining enough heat to ensure a long shave.

General design and functions

Travel mug

Travel mug.^[10]

Much of the mug design aims at thermal insulation: The thick walls of a mug, as compared to thinner teacups insulate the beverage to prevent it from cooling or warming up too quickly. For the same reason of thermal insulation, the mug bottom is often not flat, but either concave or has an extra rim. This reduces the thermal contact with the surface on which a mug is placed and often leaves a characteristic O-shaped stain on it. Finally, the handle of a mug distances a hand from the hot surface of a mug. The small cross section of the handle reduces heat flow between the liquid and the hand. For the same reason of thermal insulation, mugs are usually made of materials with low thermal conductivity, such as earthenware, bone china, porcelain or glass.^[11][12]

To further improve thermal insulation, a travel mug (introduced in the 1980s) is better for transporting hot or cold liquids. It may or may not be a vacuum flask, but it is usually well insulated and completely enclosed, with an easily closed air-tight cover.^[10]

Decoration

Smashed mug

As a ubiquitous desktop item, the mug is often used as an object of art or advertisement; some mugs are rather decorations than drinking vessels. Carving had been traditionally applied to mugs in the ancient times. Deforming a mug into unusual shape is used sometimes. However, the most popular decoration technique nowadays is printing on mugs, which is usually performed as follows: Ceramic powder is mixed with dyes of chosen color and a plasticizer. Then it is printed on a gelatin-coated paper using a traditional screen-printing technique, which applies the mixture through a fine woven mesh, which is stretched on a frame and has a mask of desired shape. This technique produces a thin homogeneous coating; however, if smoothness is not required, the ceramic mixture is painted directly with a brush. Another, more complex alternative is to coat the paper with a photographic emulsion, photoprint the image and then cure the emulsion with ultraviolet light.^[13]

After drying the printed paper, called a decal can be stored indefinitely. When a decal is applied to the mug, it is first softened in warm water. This detaches from paper the gelatin cover with the printed image and this cover is transferred onto the mug. The mug is then annealed at 700–750 °C that softens the top surface of the mug thereby embedding the image into it.^[13]

Storage

Mug rack on research ship Thomas G. Thompson

Mug tree

A popular way to store mugs is a wooden or metal pole on a round base with arms to hang mugs by their handles that is known as a 'mug tree'.^[14] There are also racks designed for hanging mugs so that they are ready to hand. Those are especially useful on ships in high waves.

Puzzle mugs

A puzzle mug

A puzzle mug is a mug which has some trick preventing normal operation. One example is a mug with multiple holes in the rim, making it impossible to drink from it in the normal way. Although it is tempting to grasp the body of the mug covering the visible holes and drink the liquid in the usual manner, this would pour the liquid through hidden perforations near the mug's top. The solution is to cover the holes in the rim with hands, but to drink not through the top, but through a "secret" hole in the hollow handle.^[15]

A puzzle mug called fuddling cups consists of three mugs connected through their walls and handles. The inner holes in the mugs walls are designed in such a way that the mugs must be emptied in a unique sequence, or they will drain.^[15]

Another puzzle mug (see picture) contains a small siphon hidden in a rod placed in the mug center. The cup holds liquid if filled below the height of the rod, but once filled above that level, it drains all liquid through the siphon to a hole in the its bottom.

The whistle mug or hubblebubble is not a puzzle but rather an amusement mug. It has a hollow handle which can be blown through the mug like a whistle. With an empty mug, only one note was emitted whereas a filled mug produced melodious trills and warblings.^[15]

In science

A continuous deformation between a coffee mug and a donut illustrating that they are homeomorphic (topologically equivalent)

The mug serves as one of the most popular examples of homeomorphism in topology. Two objects are homeomorphic if one can be deformed into the other without cutting or gluing. Thus in topology, a mug is equivalent (homeomorphic) to a doughnut (torus) as it can be reshaped into a doughnut by a continuous deformation, without cutting, breaking, punching holes or gluing.^[16] Another topological example is a mug with two handles, which is equivalent to a double torus – an object resembling number 8.^[17] A mug without a handle, that is a bowl or a beaker, is topologically equivalent to a saucer, which is more evident as a raw clay bowl can be flattened on a potter's wheel.^[18]

Wooden mug.  Glass mug

References

See also

Wikimedia Commons has media related to: Mugs

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