Fuut (and everyone), your posts about Raku are wonderful. Please keep sharing as much as you like!
steanze wrote: ↑Thu Mar 29, 2018 12:07 am
I have a question about Raku that perhaps you can answer. I know that traditionally Raku glaze contained (and leeched) lead. Are contemporary potters still adding lead to their glazes? I have heard of some lead-free Raku, but I wonder whether that's how all Raku is made nowadays, or whether there are still many pieces with lead. Thanks!!
steanze, traditional Japanese raku does include some lead, although not a great deal. In tea ceremony, matcha is prepared and drunk off almost immediately, so there is too little time for any lead to leach into the matcha. That's what they say, anyway.
I'm going to quote Joseph Justice, of the late lamented
Tea Toys site, on the subject of Raku wares:
The rakuware [in Japan] is made with a tiny proportion of lead to make the glaze melt at the low temperatures rakuware is fired at (approx. 1000 C for black; 800 C for red; “real Raku” is fired at 1200 C and 1000C respectively).
When using a red rakuyaki bowl for koicha, be careful (before class) not to wipe the bowl with the chakin too strongly. I have seen a red rakuyaki bowl lose a whole side in the grasp of a male student! It is sometimes, falsely, said that red raku will melt in hot water; I do not think that is true but red rakuyaki are very soft.
The only danger from lead in any glaze comes with prolonged holding of an acid liquid in the utensil, which will leach out the lead. This should NEVER happen in a rakuyaki teabowl, since the matcha is not acid in nature and it is in the bowl for such a short time.
One way to help keep the bowl clean in the pores is to soak the bowl for about 5 minutes before using. I heard this directly from the present Kichizaemon 15th himself. Especially in winter, if you use hot water, the bowl will not absorb the heat from the tea and even the last guest will get a drink of hot tea; too hot and the poor shōkyaku [first guest] can hardly drink it much less savor the flavor, so finding just the right temperature requires much experimentation. Soaking too long is a bad idea, I can say from personal experience, because the “special smell” of the clay becomes too strong.
After using a rakuyaki bowl or any utensil, it takes several days for it to dry out again. Leave the bowl right side up, in the shade, on absorbent towel or paper. The water will soak through so have something that won’t be affected underneath.
If some rakuyaki mukōzuke dishes for kaiseki should come into your hands, the same principles apply; soak with water before using to prevent the sauce from soaking into the ceramic. In Japan the rainy season in June brings the danger of mold developing in the pores where there is the slightest trace of organic matter or water so you really need to dry things out. Heating gently might be possible but it is dangerous for valuable works.
Needless to say, you SHOULD NOT use vinegar or citrus juice of any kind to make the sauce.
Lastly, American raku should generally be regarded as unsafe for food consumption. Not just because of the lead, but also other metals that give it that glorious iridescence. I believe the clay is more porous than Japanese raku, too, which would encourage greater leaching. I understand that some potters have made lined or "food-safe" American raku vessels, but personally I would play it safe and not eat or drink from them.
Edited to gloss the word shōkyaku