High-fired stoneware is valued for its strength, durability and vitrification. Traditionally, achieving those properties has meant firing to around 1200–1300°C.
But higher temperatures mean more energy and greater strain on kiln components. For studios, colleges and ceramic producers firing regularly, those costs add up.
What if you could achieve the performance you need at a lower temperature?
Why consider mid-fire?
- Lower energy use: our laboratory testing recorded a 16% reduction at 1160°C compared with 1260°C.
- Less strain on kiln elements: lower peak temperatures can help reduce wear and maintenance.
- Stoneware performance: a body formulated for lower-temperature vitrification can achieve low absorption without conventional high-fire temperatures.
Results depend on the clay body, glaze, kiln and firing conditions. Mid-fire is about choosing a suitable ceramic system, not simply turning down the kiln.
What is mid-fire ceramics?
Mid-fire sits between traditional low-fire earthenware and high-fire stoneware and porcelain. The important question is not just the firing temperature, but what happens to the clay body at that temperature.
As clay is fired, physical and chemical changes make the body increasingly dense and less porous as ingredients melt, so filling the microstructure. This is Vitrification.
A properly formulated mid-fire body can achieve the strength, durability and low absorption required for its intended use at a lower temperature than conventional high-fire stoneware.
Lower firing doesn't have to mean lower performance.
How much energy could you save?
In our electric laboratory kilns, testing under similar loading conditions showed a 16% reduction in energy consumption at 1160°C compared with 1260°C.
Your own savings will vary with kiln size, insulation, element condition, firing programme and load density.
The principle is straightforward: if your clay and glaze achieve the required result at a lower temperature, there is energy to be saved. Across regular firings, that difference becomes more significant.
What about kiln element life?
Repeated high-temperature firings place considerable strain on kiln elements. Reducing the peak temperature can help extend their life.
During LoStone development, our testing indicated that firing at its lower vitrification temperatures could extend element life by up to three times, depending on the kiln and firing conditions.
For busy studios and production environments, that could mean:
- Fewer element replacements.
- Less maintenance and downtime.
- Lower ongoing operating costs.
Lower firing, lower carbon footprint
Reducing energy consumption isn't only about lowering your firing costs. It can also help reduce the carbon footprint associated with every firing.
A kiln requires a significant amount of energy to reach and maintain high temperatures. By using a clay body that can fully vitrify at a lower temperature, you can reduce the amount of energy needed to complete a firing – and, depending on the source of that energy, reduce the associated carbon emissions too.
For an individual firing, that reduction might seem relatively small. But for busy studios, colleges, production potteries and manufacturers firing kilns week after week, those savings can accumulate over time.
There are wider benefits too. Extending the working life of kiln elements means fewer replacements, reducing the materials, manufacturing and waste associated with maintenance.
Of course, firing temperature is only one part of the environmental impact of making ceramics. But where we can achieve the same performance while using less energy and placing less strain on our equipment, it makes sense to do so.
For us, that's an important part of the thinking behind LoStone: not compromising on the finished ceramic, but looking for smarter ways to get there.
Mid-fire is not under-firing
Firing a conventional high-fire stoneware body 100°C lower will not necessarily produce the same result. A body fired below its intended maturation range may remain more porous and fail to achieve its intended properties.
The clay must be formulated to mature and vitrify within the lower firing range.
That is the distinction between a mid-fire system and simply under-firing high-fire clay.
How LoStone brings the temperature down
Our technical team developed LoStone to achieve genuine stoneware performance and full vitrification at significantly lower temperatures.
- Original LoStone range: developed to fully vitrify at 1160°C, around 100°C below traditional high-fired stoneware.
- LoStone Dune: its recently improved recipe can achieve full vitrification from 1120°C, with a wider firing range and improved consistency.
Development continues across the range, with the aim of reducing vitrification temperatures while maintaining performance, consistency and quality.
Explore the LoStone clay range.
Choose a complete clay and glaze system
Moving to a different firing temperature means considering more than the clay. Your glaze must also mature correctly and work with the body.
The LoStone range extends beyond plastic clay bodies to include:
- LoStone Casting Slips for lower-temperature vitrified stoneware casting.
- LoStone Mid Fire Glazes developed for this firing range.
Think of mid-fire as a complete ceramic system, rather than simply a lower setting on your kiln controller.
Do you need to fire that high?
Some bodies, glazes, techniques and applications will always require high-temperature firing. Mid-fire is not a replacement for every process.
Before changing your firing temperature, consider three questions:
- Will the clay body fully vitrify at the chosen temperature?
- Will the glaze mature correctly and work with the body?
- Will the finished piece meet the requirements of its intended use?
If those requirements can be met at a lower temperature, firing higher than necessary may simply use more energy and put more stress on the kiln.
For studios, education settings and ceramic producers, mid-fire offers a practical way to reconsider firing costs without assuming that higher always means better.
