A guide to those words which sometimes confuse
BLISTER and BLOAT
A blister is a glaze fault sometimes created due to over glazing or severe over-firing which can cause the glaze to boil and create bubbles, some of which burst to form craters. The surface of the glaze is very unpleasant and looks like a boiled mass of bubbles, craters and pinholes. Whereas a bloat is a body fault looking like a very big blister or bulge. Caused by gas bubbles forming in the body and getting trapped under the surface of the piece by the vitrifying clay surface during firing.BISCUIT and BISQUE
Actually the same thing! But 'biscuit' is the Potteries way of saying it. Biscuit ware is undipped pottery which has been fired once, not glazed. Biscuit is the clay piece when it has been fired once to give it sufficient strength to be glazed or decorated. Biscuit ware feels dry and coarse. Jasper and Parian wares are left purposely in their 'biscuit' state but they are a particular ceramic recipe called stoneware which is particularly strong and non-porous. Earthenware biscuit is porous. Biscuit firing temperature? Earthenware around 1100°C to 1150°C, Bone China around 1200°C to 1250°C.
BOTTLE OVEN and BOTTLE KILN
So what's the difference between a bottle oven and a bottle kiln? Good question! Actually there is a big difference.
Bottle ovens or bottle kilns are the terms applied to a variety of complex brick-built, coal-fired ovens and kilns once used in the Potteries. They were important tools of the industry.
As with all Potteries terms the usage of the words kiln and oven varied from factory to factory and from town to town but over time the terms became interchangeable.
Most of us assume them to be the same and to do the same job. And although both ovens and bottle kilns have that curious bottle-shaped chimney, and both were fired with coal, there is an important technical difference between the two.
Those known locally as 'bottle ovens' were used to fire pottery to 'biscuit' or 'glost'.
The ones referred to as 'bottle kilns' were used in either:
A) the decorating process - muffle kilns
B) the preparation of raw materials for ceramic bodies - calcining kilns
C) the preparation of glazes and colours - frit kilns.
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| Bottle Oven - Bottle Kiln Both at Gladstone Pottery Museum, Longton Photos: Terry Woolliscroft Collection Date: 2024 |
There was also variation in how ovens were constructed. Some had independent 'hovels' where there was a working space between the chimney stack and the firing chamber. And many were enclosed within buildings and had the chimney stack (the ‘neck’ of the bottle) constructed on top of the firing chamber, and supported on an outer ‘skeleton’ structure.
In addition, by the late 1800s, both 'updraught' and 'downdraught' variants were available. In a downdraught oven the intense heat during firing was re-circulated in the firing chamber.
There's more to it than meets the eye.
We are fortunate in the Potteries in having having examples of these. But only just! Of the 2100 or so bottle ovens and kilns which were used at their peak in the 1930s, fewer than fifty now remain. And some of them are in terrible condition.
OTHER TYPES OF KILN
Kilns for the firing of bricks and tiles were not bottle shaped at all - they were described as beehive kilns. They generally operated downdraught and had a separate tall chimney and no hovel.
NO TWO ALIKE
No two bottle ovens or bottle kilns were the same. They were all built differently; the vast majority without architect drawings. Many were built 'by eye' and based only on the experience of the oven builder and the requirements of the factory owner.
An old bottle oven builder, Tom Clewes of Longton, told me
at the Last Bottle Oven Firing in 1978
"They just went up. You won't find any of these ovens drawn on paper
since you just built them.
We did it on a day-work basis and got on with it."
The decorative brickwork at the top of the hovel chimney was created on the whim of the builder and owner.
In their heyday, the different types of bottle oven and bottle kiln were not specifically listed or classified. People in the pottery industry knew exactly what they were, so why bother listing them!
Of the 2000 or so coal-fired bottle ovens and kilns which once littered the skyline of the Potteries only 47 remain standing complete today (2025). Firing them is no longer permitted, the Clean Air Act of 1956 signalled their decline. They were replaced with kilns using the alternative fuels of electricity, gas and oil.
Sources:
1) Alfred Clough, the 'fireman' responsible for the Last Bottle Oven Firing in The Potteries in 1978. He was a local pottery manufacturer and at one time owned over 30 pottery factories.
2) In 1921 Ernest Sandeman described the various types of oven and kiln in his book 'Notes on the Manufacture of Earthenware'
CHINA and POTTERY and PORCELAIN
Beware this can be complicated! In the Staffordshire Potteries, the word POTTERY is the noun generally used to describe any type of 'body.' For example, it could mean earthenware, china, stoneware, or porcelain. So, pottery does not describe an individual ceramic recipe, it is a collective noun. In the United States the word CHINA is used in the same way that pottery is used in the Potteries. It is their collective noun. However, in the Potteries the word CHINA is the name given to a particular and specific pottery recipe. For instance bone china. (Note that there are other recipes of china, for example fine china, vitreous china, or stone china.) In the UK, generally, the word PORCELAIN is used to mean fine, up-market porcelain or china whereas the word POTTERY is used to refer to earthenware or stoneware. Yes, it’s complicated. More about recipes? here>CLAY and BODY
Clay is one of the raw materials which go into making a ceramic body, using a recipe.CRACK-CRACKED and SOUND-CRACKED
Pottery which was found to be cracked after its glost firing was usually scrapped as useless. It was described as LUMP or PITCHER and usually sent to the shraff tip. However, some entrepreneurs in the industry were able to make money from selling cracked pottery - depending on how cracked it really was! Here, to explain is a quote from Brian Milner. He was one of those entrepreneurs in the 1960s, 70s and 80s. "We used to buy China teacups from Ridgways. These were termed "crack cracked" and "sound cracked". I am not kidding. They were [packed] 40 dozen in a teachest and we used to buy about 12 chests every 2 weeks. We would sound every one of the "crack cracked" and find a lot of sound ones which we used to decorate and we were still able to sell the really cracked to market men."DINNER and TEA
A potter's dinner is eaten in the middle of the day, at lunchtime. Lunchtime is regarded as a posh dinner time. Tea is eaten at dinner time. Dinner in the evening would be regarded as posh. More here>EARTHENWARE and STONEWARE and PORCELAIN
Very (very very) broadly speaking there are three types of pottery: earthenware, stoneware and porcelain.- Earthenware is a clay body fired at a comparatively low temperature, about 750 to 1100°C. It is porous and has to be glazed to make it impervious to liquids.
- Stoneware is hard, impervious and made from a clay and flint mixture, fired at a high temperature of 1,200 to 1,400°C. Vitrification (the formation of a glassy outer surface) occurs at these high temperatures, so it does not have to be glazed unless a fine or coloured surface is required.
- Porcelain is fine ceramic and originated in China in about AD 700. It is made from fine white-firing clay, fired at a high temperature, and is translucent. Bone china (invented by Spode in the Stoke-on-Trent Potteries around 1800) is regarded as English Porcelain.
EDGE - RIM - VERGE
Names given to the parts of flatware (plates, saucers dishes etc)
- Edge The outermost part of the piece.
- Rim The part between the edge and the verge. May be used for the placing of salt or mustard.
- Verge The part creating the slope between the rim and the centre of the flatware.
Interestingly, after WW2 the depth of the verge was increased to cope with the American habit of only using a fork to eat and needing something to push the food against. Many thanks go to Andy Finney for sending me this snippet.
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| Names given to the parts of flatware |
GAPPERS and KISSERS
Opposites. Faulty products, mainly flatware (plates). Words used to describe distorted plates as seen in a bung, usually in the biscuit state, probably before selection (inspection). Gappers is used when the distortion makes rims of plates separate from each other in the bung to create an obvious gap. Kissers is used when the distortion makes the rims of the plates touch. These words are possibly peculiar to the Steelite, and possibly the Royal Doulton, pottery factories. Many thanks go to David Tabbernor for sending me these. October 2019HUMPER and WHIRLER
A humper is a fault on pottery flatware. It appears as a domed base, causing the plate (or other flatware) to bow upwards. It looks ugly and causes gravy to accumulate in a ring around the edge of the plate. Regarded as seconds, or if its really bad, lump. On the other hand, a whirler is the exact opposite. It's also a pottery flatware fault, but this time refers to a plate with a bowed base so that it doesn't sit flat on a table but spins or whirls around. Giddy making. Causes gravy to accumulate in a pool in the middle of the plate.JIGGER and JOLLEY
A jigger is a potter's machine for making flatware. A jolley is a potter's machine for making for holloware. Look for the OLL in jOLLey and hOLLow and you'll remember it! (Interestingly, and to confuse matters, in the 1840s Jolley was the word used for making flatware.) More here>MAIOLICA and MAJOLICA
Maiolica pottery has its origins in Spain and Italy. It is earthenware, fired to the biscuit stage, then covered with opaque, white, tin glaze and then superbly painted directly onto the unfired glaze surface with decoration in Renaissance styles. The decoration is so detailed that it is akin to a painting. The piece is then fired again. Majolica pottery has its origins in Victorian Britain. It is also earthenware and also fired to the biscuit stage. But it is then decorated with richly coloured, glossy lead glazes, frequently in a relief decorated and naturalistic style. The piece is then fired again. The names of these two types of pottery are very often confused and, quite frankly, misleadingly mixed up. Take care with this one, there is a lot of incorrect information posted on the web! This is a helpful site here> |
| Majolica on the left vs Maiolica on the right |
MUFFIN and MUFFIN DISH and MUFFIN PLATE
An American Muffin is a small domed spongy cake made with butter, plain flour, baking powder, bicarbonate of soda, sugar, salt, milk, and a large egg. An English Muffin is leavened bread, beloved by the English aristocracy particularly in the early 20th Century and served in a Muffin Dish. A Muffin Dish should not be confused with the Muffin which is a small pottery plate measuring 5 or 6 inches in diameter. A Muffin is similar to a TWIFFLER or TWIFLER or TWYFLER - but of different diameter.OVEN and KILN
A bottle kiln is the same as bottle oven. But not quite! The words do tend to be interchangeable. But the word oven usually meant the biscuit or glost firing ovens and the word 'kiln' usually meant the enamel firing kiln, hardening-on kiln or calcining kiln. But usage did vary from factory to factory, so its complicated and difficult to be precise. More here> at The Potteries Bottle Oven website.PEGGING and STOPPING
Pegging is the process of repairing a crack in a clay piece by filling it with slip and smoothing it over before the piece is fired. Hopefully it will be invisible after firing. Stopping is the process of filling a crack in a fired piece using a mixture of pre-fired body, ground to a fine particle size, and mixed with a resin which sets hard and seals the crack. Many thanks to David Broadhurst for suggesting these two words for inclusion. March 2016 Additional: "Pegging can also be done in the dry clay state by scraping the crack with a wooden peg and then rubbing usually with a bone handled knife. Bone handled knives were also used to repair fish cracks on the outside rims of closets."PLACER and PLACER
A placer is the person, usually male but could be female, who places individual clay pieces or dipped biscuit pieces into saggars before they are placed (or set in) the oven for firing. If the firing was glost then 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 placer is also the man who fills or sets the oven with saggars containing the ware which had been placed into the saggars by the placer. (Sorry, but I agree it can be confusing to a beginner!) The placer works for the cod, his boss.POTTERY FAULTS
The description of a classification of the quality of pottery ware - the nine grades of pot!You may need to sit down.1) BEST
First quality pottery. Fabulously good
ware. Hoorah! Sometimes called FIRSTS. However, there is no such
thing as a perfect pot. Never. Whether it’s a teapot or a toilet every single piece
will always have some sort of slight blemish - this is the very nature
of pottery.
2) BEST SECONDS
Not bad enough to be SECONDS
but not good enough to be BEST.
3) SECONDS
Imperfect pottery. Not BEST
and not THIRDS, LUMP or PITCHER. So,
it's slightly blemished or faulty and sold at a slight (or sometimes big) discount.
4) WORSER or WORST SECONDS
Slightly more imperfect than SECONDS.
Obviously.
5) A DEGREE WORSER
Worse than WORSER SECONDS,
or even WORST WORSER. A tad confusing, but not THIRDS.
6) THIRDS
This signifies that the ware is
well below the usual BEST, and not even good enough to fall
within the description of SECONDS. But better than LUMP.
The ware is still marketable - sold to hawkers or market stall holders. Badly
twisted ware, crooked holloware, nipped ware and whirler plates fall into this
category.
7) LUMP
Massively faulty pottery. So bad
that it is worse than WORSER SECONDS and even THIRDS.
Lump is almost, but not quite, the lowest quality of ware that leaves any
potbank, and usually it is ware that has just managed to escape being
deliberately smashed. Whilst there may have been possibilities in some china
shops of disposing of SECONDS, or even THIRDS the
risk of dealing in LUMP is 'too great to be incurred light-heartedly.
'Top-end, high-grade potbanks see to it that LUMP is sent to SHRAFF
as PITCHER. Usually, about 100 years later, LUMP
appears on TV shows as 'rare and valuable.' That’s irony!
8) PITCHER
Worse than LUMP. To
be thrown away. Useless. BOST. Broken. But strangely saleable, at
a price, in some quarters, possibly!
9) BOST
Broken pot. It is a well-known and
indisputable fact that pottery is useless if you drop it.
There may be more than nine - let me know 😉
PUTTER UP and SITTER UP
A putter up is an occupation, usually female, in the dipping house. She either takes biscuit holloware (cups for instance) from a ware basket, and places them onto a board in front of the dipper ready for dipping or she takes the recently dipped holloware and places it onto trays or bats or ware boards before they are taken away to dry before the glost fire. A sitter up is a bottle oven fireman's assistant (maybe the fireman's apprentice). He kindles, cajoles, guards, tenders and baits the oven while the fireman takes a break during the firing cycle. The sitter up will get the oven up to a high temperature after about 20 hours of firing, then the fireman takes over to finish off the fire completely. See also RUBBER UP here>RIDDING and REBUILD
This is all about Bottle Ovens. Ridding was an essential process in the life of a bottle oven. It entailed the thorough repair and relaying of the flues, oven bottoms, and bags. This was a major operation which put the oven out of use for some considerable time. It needed to be done every three years or so - depending on the work that the oven had been put to. In 1920 ridding would cost around £30. A rebuild was, as it says, a complete rebuild of a bottle oven, excluding the hovel, and was required, on average, every 20 years. More here> at The Potteries Bottle Oven website.SAFF RUCK, SHAFF RUCK, SHORD RUCK, SHAWDRUCK, SHARD RUCK, SHERD RUCK, SHRAFF RUCK, SHRAFF TIP, SAFF TIP, SAFFER TIP, PITCHER TIP. And sometimes simply SAFF
Don't get confused. They all mean the same thing. A rubbish tip of waste potters moulds, broken saggars and faulty ware such as lump or wasters. A heap of broken crockery! Photo here >SAGGAR and SAGGER Same thing! But saggar is the preferred spelling of those in the know.
SAGGAR SHOP and SAGGAR HOUSE
The saggar shop was where saggars were actually made. It was where the saggar maker and his saggar maker's bottom knocker created clay saggars which needed to be fired before use. The saggar house was where they were used. It was here that they were placed (filled) with either clay or glazed biscuit pieces ready for placing (setting) in bungs, in the bottle oven, prior to firing. |
| Saggar House - placing ware into saggars before being taken into the kiln for placing before firing. Photo: source unknown Date: unknown |
SINK and WASHBASIN and LAVATORY
A sink is used in a kitchen, not a bathroom. A washbasin is used in a bathroom. A lavatory is not a toilet, it's a washbasin but not a sink. Confused? Here is a more in-depth explanation but it's messy, complicated and a tad confusing, so bear with me! In the good old days, in the UK sanitaryware industry, sanitary pottery casters and warehouse packers, called a WASHBASIN a TABLE. But why? Well, in the late 1800s when large WASHBASINS were designed to stand on legs rather than a single column pedestal (as is common in the UK today, 2015) the washbasin actually looked like a TABLE. But actually, the correct word, in those days, for a WASHBASIN or TABLE was LAVATORY. The word LAVATORY is derived from the Latin word LAVARE, meaning 'to wash.' Nowadays, a TOILET is often mistakenly called a LAVATORY since this is regarded as polite. But technically, it is incorrect. Of course, while it would be correct to wash your hands in a LAVATORY or WASHBASIN or SINK (see below) it would be odd to wash your hands in a TOILET, or worse still, to do something 'exceptional' in a LAVATORY, WASHBASIN or SINK.
SORTING and SELECTING
Sorting is the removal of stuck-on pips which have been used to keep pottery apart during a glost fire. Its the same as as 'ginneting.' But selecting is the inspection of the product after a processing stage to look for faults.TRADE SIZES
The Staffordshire pottery industry had a uniquely peculiar system for describing the sizes of its products. To an outsider and the uninitiated, it was complicated, messy, inconsistent and arbitrary. To those in the know, a manufacturer and his workers, it was easy to understand but skewed to the benefit of the boss.The nominal Trade sizes of flatware, such as plates and dishes, differ from the Actual sizes in inches. For example, a Trade 8” plate usually measures Actual 9” and a Trade 10” plate measures Actual 10.5” or more. Similarly, a 16” Trade oval meat dish would truly measure 18” Actual and the whole nest of dishes will be greater in Actual size than the nominal Trade size.
But, probably, the most perplexing point is encountered in connection with holloware. Jugs. teapots, pudding bowls and the like are described under trade terms such as 24s, 30s and 36s, each gradation occurring in spans of sixes. And, counter-intuitively, the smaller the number the larger the size! The full range of Trade Sizes was 6s, 12s, 18s, 24s, 30s, 36s, 42s, 48s, 54s, and 60s. The underlying principle of this arrangement appears to have come down through the generations, and the apparent inconsistencies are accounted for by the fact that originally, pottery was sold by the basket, in what were known as "warehouse dozens”. The large size jug or teapot or bowl would be twelve to the dozen, and called a 12s; the next smaller size would be eighteen to the dozen, and styled an 18s; the pint size would be twenty-four to the dozen, and called a 24s and so on down or up the scale. To add to the confusion, one manufacturer's sizes do not necessarily conform with those of other manufacturers; the shapes may be modelled to bigger or smaller capacities.
During the early 20th Century the system was changed and articles were sold in dozens of twelve, yet the old method of describing the sizes persisted well into the 1990s.
TWIFFLER and MUFFIN and PLATE
These are three different sizes of plates. Read on. In 1843 the Potters' Union began putting right the wrongs which they believed their employers had forced upon their members. One concerned the sizing of flatware and the price which a potter would be paid for making each size of plate. Here is an extract from The Staffordshire Potter by Harold Owen, originally published in 1901. "The Mystery of the Muffin. The Union of 1843 found, at its birth, a strike already in progress … but there was a new grievance. In the trade, the different size of plates are distinguished by separate names. The largest size is called a "plate," the next a “ twiffler," the smallest a "muffin." One of the employers, whose workmen had struck, re-christened the series. He called the plate a twiffler, the twiffler a muffin, and the muffin, in the words of the workmen, he “sent to God knew where.” In other words, the men were told that they must make plates at the same price as twifflers, and twifflers at the same price as muffins. There was no alteration in the sizes - the nomenclature and prices alone were affected. This is an interesting circumstance, inasmuch as it is the earliest recorded example of a practice in the trade which subsequently became very common as an oblique method of a reduction in wages."WAD and DOD
Wad is a rope-like strip of specially-formulated fireclay or saggar marl squeezed through the die in a wad box. Wad is used as a cushion between saggars when they are placed together, one on top of an other, in a bung, in the oven. In addition to the effect of levelling the bung, wads also seal the uneven joint between the saggars, thus preventing smoke and fumes from the the fires coming into contact with the ware during firing. Dod is a soft clay squeezed through the die in the dod box to give a strip of the required cross-section shape. The strips are cut into lengths and bent by hand while soft to form a handle for a teacup or jug.WICKET and CLAMMINS
The wicket is the open entrance into a bottle oven. Whereas the clammins is the name of the brickwork built to seal the wicket before firing.