Ah, the pots are here! Click on picture to see the small grains of sandy texture on surface. I used this pot very briefly today. Will post the effects it has on tea later. They are thicker and heavier, less refined, but gives off a sturdy feel. I did shock this pot with hot water without rinsing. It is much more tolerant of temperature fluctuation. These pots need not to break in before use. There is no clay smell at all even with the first infusion. Pretty amazing!
Yuan Xing Hao is established in 1847 in Feng Xi (Chao Zhou area), Guang Dong Province, known to be the best local pot maker. This batch of pots (20) are made of sandy Zhu Ni (local Chao Zhou red clay) by Wu Pei Liang.
Wu's family has its own secret recipe for clay. What's known to outsiders is the basic process. Raw clay materials are ground into dust, sifted and soak in water for 2 years, then drained and made into blocks of damp clay put away for 10 years before use. Small grains of sand are added for texture and also to increase porosity. There are 2 standard types of sandy grains used by the Wu's family.
1, raw clay materials ground into small grains then added directly into ready for use cured for 12 years clay. After firing, both clays shrink at similar rate, approximately 12%.
2, defected/broken pots are ground into small grains then added into ready for use cured for 12 years clay. After firing, clay shrinks at 12%, sands at 0%, therefore creates more pores.
Chao Zhou pots range from 2% to 5% porosity depending on the clay mix, each maker/family tradition have different recipes not shared with others. I do not have the answers to them, but all clays are pure, just different composition of texture and curing process.
Pots I currently have in stocks are mixed with the later type of grains therefore with higher porosity of up to 5%. Zhang's family pots are approximately 2% due to the fine clays are used.
These pots are fired at 1160 C to 1180 C.