"One of our most exciting discoveries on the Spring 2019 China trip was this exquisite white porcelain known as Yang Zhi Yu Ci 羊脂玉瓷 “Mutton Fat Jade Porcelain”. Despite being uncolored and generally unornamented, its soft matte lustre and almost featureless whiteness caught our eyes immediately. Named after a high-grade, translucent grade of jade, these unglazed wares are made of an especially soft, fine, and pure grade of porcelain usually reserved for religious statuary. These wares come to us from Dehua, Fujian 福建德化, one of China’s famous porcelain production centers. Unlike the more famous Jingdezhen porcelain wares, the emphasis among Dehua potters is not on painting on the porcelain but on carving it with fine details. Dehua potters are therefore intimately familiar with the texture, quality, and softness of the unglazed clay body, leading to the distinction of different grades of porcelain. Mutton Fat Jade Porcelain comes from the center of the porcelain seam, and is prized for its purity. Only recently - in the past few years - did this exceptionally high grade of porcelain come to be used in its unglazed state for gong fu teaware. The material itself has striking optical properties; though thick, the wares are highly translucent and conduct light as a gentle glow that illuminates the clay body.
Unglazed porcelain stains notoriously easily, and cheap glazed porcelain often develops stains where the thin glaze wears through with extended use (things you learn running a tea house). Though unglazed, the mutton fat jade doesn’t stain but maintains a snowy white surface, assuming it is put away clean. Soap and abrasion aren’t necessary, but wiping the wet wares dry with a cloth is enough to maintain a stain-free exterior. I’ve used the same mutton-fat jade gaiwan and gong dao bei 3-5 times/week, steeping 4-8 pots of tea per shift, at the tea house for more than 10 months at this point. The interior of both gaiwan and gong dao bei have no discernible marks but have a subtle, even, ivory color. The outsides remain strikingly white, and the patina conveys no discernible flavor to the tea.
Here are some other reasons I love Mutton Fat Jade Porcelain:
The soft, matte texture of this clay makes these wares extremely satisfying to the fingertips and lips.
They conduct heat in a diffuse way that makes them comfortable to hold at high temperatures and seem to insulate well.
The teapot has a remarkable golf-ball style filter that would be sexy on any pot.
Finally, the interface between the unglazed lid and mouth of the gaiwan gives it a firm and stable grip and smooth, focused pour. As I write this, I realize that there is an effect that the satiny, soapy texture of the clay has on all the fluid dynamics of the pouring process - the smoothness of the pour exiting the gaiwan, the way the spout of the gong dao bei pulls the last drip back up, even the pour of the teapot, all exhibit a “slow” quality. By this I don’t mean that the vessels drain slow, but that the velocity at which water and tea flow out of them feels slower - a phenomenon I observe with other unglazed wares such as Zisha and Dai clay. Ultimately, I feel like this “slowness” gives me more control and leads to less dripping, and less spilling in general.
My default tea set, pouring tea for hours on end multiple days a week at a busy tea house, is made out of this clay. A combination of the physical properties of the unglazed clay and the ability to steep any kind of tea in it without switching vessels, as well as the genuinely pleasing feel of the wares, make me want to put a lot of mileage on that set. These have proven hugely popular at Guan Yin Tea House and the more interest I get in these the more I’ll be able to get new wares from the same factory - I intend to visit some workshops and kilns in Dehua this coming year. I’ve also never seen a porcelain mine so maybe one of those. Either way, in summary, I love these wares, they are magical.