Reduction firing ceramics


It is a very old ceramic ware making process where the pots are burnt similar to how it was done several thousand years ago B.C. when the ceramics was burnt in a hole made in the ground. This is so called black or reduced ceramics. Nowadays the burning process is done in special kilns. The reduction firing process was abandoned during centuries. However, thanks to enthusiastic Latgalian ceramics, who have been learning and investigating antique excavation records, making experiments and using their own knowledge, it was renewed. It is becoming more and more popular and many ceramics have been making reduced ceramic ware not only in Latgale, but also in other regions of Latvia. These days reduced ceramic ware can be found in the countryside, in the appartments in town, in salons,as well as in restaurants all around Latvia. The sympathy about such ceramics has gone even beyond the borders of Latvia.

Most important and positive factors of this artisan movement:
* Industrial processes and technology are not used in making the ceramics.
* Reduced ceramics is an ecologically clean product. In the process of making it ecological as well as health and nature friendly technology is used.




In the process of making ceramics it is very important to use high quality clay. Even though Latgale is famous for its loamy soil, not all clay that is dug out of it is suitable for making ceramics. At first, the structure of the clay is very important – it’s crucial not to have any lime or too much sand in it. It is also necessary to purify the clay from organic materials that might be in it (stems of trees, grass, stones, insects a.o.). In various places clay differs due to its content and minerals in it as well as due to its heat resistance. Low heat resistant clay is not suitable for making ceramic ware. Pottery can be made using different methods. However, individual ceramists most commonly use a potter’ s wheel. Some of them use also hand building technique when the ware is made by constructing coils of clay by hand.
For firing the kiln, it needs to be full with ceramic ware. Half full kiln cannot have the necessary temperature because the density is important. The number of ware can be different due to their size. The ware is placed in the kiln on each other, though each dish should be stable in its place. When all the ceramics is put, they are covered with clay smithereens. The kiln is fired for about 12 hours increasing the heat inside it as well as letting the open fire through holes inside the kiln. In the end the open fire goes straight between the pots. The ceramic ware in this way is fired with “ live”  fire and look red like heated metal. The highest temperature in the kiln is about 1050 Cº, which can be achieved using wood for firing. The firing process is finished with damping. The kiln is walled up so that the oxygen doesn’t get inside. In the process of burning out the oxygen the ware becomes black. This is so called reduction firing.
Usually the ceramic ware is taken out in two or three days after firing the kiln. Only after the ware is completely cooled it is waxed using the combination of bee wax and vegetable oil. The waxing is done to make the ware water resistant. After this process the ceramics becomes smoother and feels nicer holding it.


Peculiarities of using the reduced ceramic ware

Black ceramic ware doesn’t daub as it is said before, the colour is achieved in the reduction process, it is not smoke nor soot or any colouring. The ceramics can be used daily; the pots can be used in the cooking process and even put in the oven. The only precaution is to make sure not to change temperature very quickly. For that reason cold ceramic ware shouldn’t be put in a heated oven. The best way to cook in the oven is to put the dish in the oven and only then switch it on. The ware cannot be put on the open fire, like gas stove, as well.
The ware can be put in the dishwasher, however it is advised to use delicate programme.
It is often asked why the bottom of the vase becomes moist. The clay is a natural and breathing material. If the vase is not waxed well and left for a long period of time in one place, condensation process is observed. For this reason, it is advised to use pads under vases and not to put them on lacquered furniture.
If you keep some salty liquids or other wet mixture of minerals that become light when dried in the ceramic ware, it will succumb to the pores of the clay. As a result the ceramic ware will have white residue spots on the surface when it is dried. Therefore, it is not recommended to keep such liquids in unglazed ceramic ware. However, dry salt doesn’t leave any residue on the dish.
Dry products, like sugar, dry salt, nuts and others are safe to keep in both glazed and unglazed ceramic ware even for a long time.
It is similar with oil bottles that are made of clay. Even though they are glazed both from inside and outside, clay has quite a lot of pores. When oil is kept in the bottle for a long time, it is drained through the pores and covers the surface of the bottle with an oily layer that becomes sticky with time. Oil bottles are good for serving or keeping the oil for a short time. They also have to be cleaned with hot water afterwards. If the bottle neck is too narrow to put a brush in it, you could use sand. Sand should be mixed with warm water, poured into the bottle and shaken well. This “scrub” cleans the inside of the dish very well.
Unglazed ceramic ware should be kept in the dry place where there is at least a little air flow. If the dishes are not dried after washing and put on top of one another, light mould spots can appear on the surface. Therefore, the dishes have to be wiped well or dried well before putting in the cupboard where there is not enough air flow.