Secondly, it is not very practical. Hand-drawn embryo products are fine and sticky, with low sand content, large shrinkage and low kiln temperature. This kind of clay clay is dense and airtight after sintering, so it is generally not suitable for making tea sets. Jianshui Zitao, on the other hand, is more breathable and suitable for making tea than Zisha. Why? The answer is to deliberately sinter at low temperature, and the finished product does not sinter! This can be guessed from the color comparison between the raw embryo and the finished product.
The raw embryo is orange with high stone yellow content, similar to purple sand vermicelli. It is speculated that the finished product should be orange, big red or purple, but it is purple black and purple brown when it leaves the kiln. Why? It is estimated that the reduction burning method is used, not the oxidation burning method of most purple sands. The kiln is closed, no fresh air enters, and the iron in the clay is not oxidized into iron oxide, but a darker iron oxide is generated in an oxygen-deficient environment. The advantage of burning black paste is that it is easy to cover up the situation that tea leaves are easy to spit black without burning.
What's the harm of not sintering? I have a ceramic beauty in my hand, which has been used for 1 years. The pot body used to be even purple-brown, but now it is a circle of dark lines (spitting black), and it will crack and leak without bumping. As a daily utensil, the service life of the unsintered pottery jar is basically 1-2 years, and it will eventually crack and leak, so it is difficult to pass on from generation to generation, let alone the collection value.
Zitao Zitao, with a purple word in its name, is not worthy of the name, and it feels a bit like a purple sand tycoon.