Glossary G-O

Here is an alphabetical list of terms used in the firing of a traditional Potteries Bottle Oven. For explanations of more general terms used in a traditional Potbank click here>


These words have been collected during a lifetime in potbanks. Some are specific to a particular factory, others are more general. Some vary from potbank to potbank and from Tunstall in the north to Longton in the south. Some are technical, and some feature the very special dialect of The Potteries. Some words are being lost as potbanks close or manufacturing methods change.


GANISTER Fireclay.

GLAZE A thin glassy layer formed on the surface of pottery during firing, making the articles non-porous and decorative. Also glaze means a prepared mixture of a powder or a suspension in water ready for application to pottery by dipping.

GLAZE FIRE Process. A potter would call this the 'glost fire.' The firing which takes place after the biscuit ware has been dipped or sprayed in glaze.

GLOSS Dialect meaning GLOST. 

GLOST Pottery pieces which have been glazed. Adjective of glaze. When ware has been glazed and fired it is described as glost. The oven in which glazed pottery is fired is invariably called the glost oven. Glost printing implies that the pattern is transferred onto the top of the glaze, as distinct from underglaze printing, which is performed before the ware is dipped.

GLOST FIRE Process. The firing after the biscuit ware has been dipped or sprayed in glaze. When glaze is fired it softens progressively as the temperature increases. Then, the constituents fuse together to create the glaze surface.  The Last Bottle Oven Firing 1978 was a glost fire.

GLOST OVEN The oven used specifically for firing glazed ware.

GLOST PLACER Occupation. Ovens department. A glost placer is the person, usually male but could be female, who places individual dipped pieces into saggars before they are placed (or set in) the oven for firing. For a glost firing he or she would also need to place wads of wad clay on the top rim of the saggar before it was taken into the oven. A glost placer is also the name of the man who fills or sets the oven with saggars containing the ware which had been placed into the saggars by the previous placer. The placer works for the cod placer, his boss.

GLOST WARE Glazed ware. That is biscuit ware that has been glazed and then fired for the second time.

GLUT ARCH Part of a bottle oven. Sometimes called a drop arch or houster arch. The brick arch below the firemouth of a bottle oven. Allows the admission of primary air to the burning coal. Also allows the removal of clinker and ash during or after the firing.

GOOD FROM OVEN  A payment system used in the Potteries. This system of remuneration allowed payment to workers only when goods emerged perfect from the oven. The ware passed through many hands before firing, any one of whom might have caused some imperfection – but unless the piece was faultless no one was paid. The imperfect pieces were sold as seconds and the pottery owner kept the income. This system was open to abuse by the pottery owner.  Abandoned by some of the better class firms such as Copeland and Minton in the 1870s but not finally abolished in 1964.

GRAFTER Equipment. Ovens Dept. Saggar making.  A flat D-shaped tool called a grafter was used to slice a flat piece of saggar marl from the dump (large lump of saggar marl clay) before use.

GRATE Part of a bottle oven. Formed by the firebars and checkers above them. An area for the burning coal.

GREENWARE Unfired pottery.


HALF-ENDER Half a building brick. Used as a scotch during placing.

HEAT WORK The combined effect of temperature and time on the pottery body during firing.

HILLERS Kiln furniture. Part of a bottle oven. A very shallow saggar used as a lid for the top of a bung of saggars. A saggar with very low sides and a full base to cap the top of a pile or bung (a stack) of several saggars. Sometimes hillers were turned upside down and used to stand on, like steps in the oven.

HOB Part of a bottle oven. Just above the glut arch. In dialect it is known as thob. "Put thee lobby on thob fur cape eat ot, duck."

HOLLOWARE Pottery which is essentially hollow i.e. cups, bowls, jugs, vases. See FLATWARE.

HORSE Equipment. Ovens department. See 'oss.

Bog 'oss, medium sized 'oss and little 'oss  in an oven

HOUSTER ARCH Part of a bottle oven. Alternative name for the glut arch positioned below the baiting mouth.

HOVEL Part of a bottle oven. The brick bottle-shaped structure which encloses the firing chamber (the oven itself), creates draught, takes away the smoke and protects the oven from the weather. May be up to 70 feet high.

HUDSON & MIDDLETON LTD The factory, in Longton, Stoke-on-Trent, here> which hosted the Last Bottle Oven Firing in the Staffordshire Potteries, organised by Gladstone Pottery Museum, in August 1978. BBC Radio Stoke Gallery of images here>

HUMP ARCH Part of a bottle oven.


INTERMEDIATE HOLES Part of a bottle oven. On the crown of the oven. Similar to shoulder holes but positioned mid-way between the shoulder and the top of the crown.

INTERMITTENT OVEN Equipment. Any potter's oven which is successively placed, fired and drawn after cooling. Bottle ovens are intermittent.


JACKED Firemouth doors or dampers which are slightly open. Also known as cracked.

JINNET  A particular shape of saggar. Rectangular box with holes in its sides through which refractory ceramic 'pins' were inserted. Two lines of triangular refractory 'saddles' were placed in the base of the saggar. Plates were then placed in the saggar and made to rest upright on the saddles, each plate being separated from its neighbour by resting on the protruding pins.


KILL Dialect. Kiln. Oven. Bottle Oven. Enamel Kiln. Tunnel Kiln. Top Hat Kiln. Intermittent Kiln. Rapid Fire Kiln.

It's where the metamorphosis of clay, during firing, takes place. It's where the irreversible change from clay to pot upon which the whole of the craft and industry is founded. The change which takes place in the kill at around 600°C. It's where clay loses its chemically-bound water molecules and can no longer be broken down by water. Once this change has occurred it cannot be reversed. Ever. This ceramic change converts fragile and crumbly dry clay from Mother Earth into hard brittle pottery. This is both a chemical and physical change to the structure of the clay. Magic by fire!

KILL FILL The amount of pottery ware loaded into the kiln or bottle oven for firing.  Manufacturers want the maximum kill fill in order to maximise profit.

KILN Equipment. An entire building (as in the case of a bottle oven) or an installation designed and used for the firing of ceramic products at high temperature. Also, as a different design, for calcining, hardening on or sintering. May be intermittent, annular, tunnel, rotary, shuttle, skate, fast fire, top hat or shaft. There will be others, too. Strictly speaking this is not the same as an OVEN.

KILN FURNITURE Equipment. Refractory supports on which pottery is stacked prior to and during firing. Crank, Dot, Dump, Pillar, Pin, Pip, Post, Prop, Ring, Saddle, Saggar, Setter, Spur, Stilt, Thimble.

Kiln Furniture

KINNDED OFF  Process.  Oven dept.  Past tense of kindle.  Getting the fire going with wooden sticks and screwed-up newspaper to light the coal. Used by Alfred Clough when he fired the Last Bottle Oven organised by Gladstone Pottery Museum in 1978.

KINDLE Process. Ovens department. At the start of bottle oven firing. Getting the fire going. Layer of coal, layer of newspaper on top of that, layer of dry wood sticks on top of that, layer of coal on top of that. Then set the newspaper alight, not with a single match but with a flaming torch (similar to an Olympic torch) - a short pole with a burning oily rag fixed at one end.   NOTE - this is not a digital text storage and retrieval device.

KINDLING Material. Used during the firing process. Dry flammable material to get the coals lit. Newspapers loose and scrunched. Dry, wooden sticks.

KINDLING TIME Process. Starting the bottle oven firing. If it is done right it won't take long and the coal gets going and within an hour all mouths should be lit.


LAMP Equipment. Portable lighting used to illuminate the inside of a bottle oven during setting or drawing. Sometimes made of metal - specially designed and constructed - with a spout from which emerged a 'tow wick'. A thick oil known as torch oil was used to soak the wick which was set alight.

LAST BOTTLE OVEN FIRING  Longton, Stoke-on-Trent, England. 1978.  The last firing of a Potteries Bottle coal fired oven organised by Gladstone Pottery Museum and took place on the factory of Hudson and Middleton (Longton) Ltd.

Author of the Potbank Dictionary, Terry Woolliscroft, baits a firemouth
at the Last Bottle Oven Firing in the Potteries 1978.
Alfred Clough, who managed the firing, looks on.
BBC Radio Stoke Gallery of images here>

LOBBY Food for the hungry potter. A delicious and nourishing and thin stew made with meat (beef or lamb) and vegetables. The recipe varies.

LONG FLAME COAL High bituminous coal, have a high quantity of gaseous ingredients which enable flames to reach the height of the inside of a bottle oven. Pottery districts were located on coalfields where this type of Black Band coal was plentiful.

LONKTON A potters' pronunciation for LONGTON.  The southern most town of the six towns (not Arnold Bennett's five towns) which make up The Potteries of Stoke-on-Trent.

LUMPING Loading coal on to the firemouths at the start of the firing cycle, before kindling.


MATURING POINT  Firing point (a combination of temperature and 'soak' time) at which the body or glaze reaches it's desired condition of colour, hardness, density, etc.

MAWL or MAU or MOW Equipment. The special tool used by a Saggar Maker and a Saggar Maker's Bottom Knocker to flatten saggar clay into a slab. Like a large wooden mallet. Oak. Kept in submerged in water when not in use to stop saggar marl sticking to it during use.

Two lads on a potbank with a mawl, mau or mow

MEDFEATHERS Part of a Bottle Oven. The brickwork used in building the flues and mouths in the oven. The dividing wall between two flues. Medfeathers, which form the flues and support the oven bottoms, are built four bricks high. Bricks used are firebrick and usually flat backs. They may sometimes be tapered and sometimes notched. Also known as Midfeathers.

MIDFEATHERS  See medfeathers - directly above.

MOW OUT or MAU OUT Dialect Saggar making. Bashing a lump of saggar marl with a mow  or mau to create a flat slab of clay for use as a saggar bottom.

MOUTH Part of a Bottle Oven. The firemouth. On average, eight firemouths were built into the oven.  It was here that coal was baited, (bet)  set alight, to raise the temperature in the oven to between 1000°C and 1250°C ( sometimes as high as 1400°C) to fire the ware.


NCB National Coal Board responsible for all coal production in the UK at the time of the Last Bottle Oven Firing, 1978.

NECK Part of a bottle oven. The top of the chimney or stack of a bottle oven.

NECK END Dialect. Longton. (Lonkton) Southernmost of the six towns of the City of Stoke-on-Trent. Further south than the 'dish cloth end.' The town where The Last Bottle Oven Firing 1978 took place.

NIBBED SAGGAR Type of saggar. With internal protrusions to support a bat, creating a double deck. Thus allowing the placing of two layers of ware in one saggar. Nibs also allowed the placing of a lid or cover or the top of the saggar to keep out dirt.

NIGHT FIREMAN The fireman's assistant. The night fireman stood in for the main fireman to give him some rest during the night. Also known as a sitter up.


ODD MAN Occupation. Ovens Dept. More than a labourer. May set his mind to virtually anything. But he worked particularly in the ovens department. One of his jobs would have been daubing clay on the clammins of an oven.

ODD WORK usually carried out by an odd man. Labourer. Maybe for odd money! How odd.

'OSS Equipment. Ovens department. Vital in the bottle oven. One-sided step ladders used by placers in the oven to reach the top of stacks or bungs of saggars. Two or three different heights were made to suit a particular oven. Made very robust with a wide top step to allow a saggar to be rested on it before its final lift to the top of the bung. The back of the top was usually cut away into a semi-circle so that it could rest against a bung which had already been placed.

Three sizes of 'oss' in use in a bottle oven

OSS OFF Potteries dialect. Kindly go away, if you would.

OT Potteries dialect word meaning very warm.

OOSTER Clinker or caked ash formed on the insides of a firemouth mainly found in biscuit ovens or glost ovens with bad fuel.

OVALS Kiln furniture. Type of saggar. Particular shape to accommodate oval product.

OVEL Potteries dialect word. Part of a bottle oven. Huge cone or bottle shaped brick structure built to fully enclose the main business-end of the oven.

OVEN  Bottle oven. Strictly speaking this is not the same as a KILN.

OVEN BOTTOMS or OVEN BOTTOM BRICK A particular type and shape of refractory building brick used in the bottle oven base. They cover the flues from medfeather to medfeather and are matched or grooved to fit into each other to create a seal and prevent sand and dirt working into and blocking the flues. Made in Berry Hill, Stoke-on-Trent.
Oven Bottom Bricks

OVEN FILL The amount of ware (pottery items) placed or set in to the bottle oven.  The factory owner would always try to get as much ware as possible into the kiln to maximise the efficiency/use of the fuel.

OVENMAN Occupation. Ovens department. Man who worked in bottle ovens. More than a labourer. May set his mind to virtually anything. But he worked particularly in the ovens department.

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