Raku and Hagi Ware

[Tead Off]

I have heard conflicting information about these 2 wares and would like someone knowledgeable to set it straight for me.

Many people claim raku is not to be used for food or drink and that both raku and hagi are porous and will either leak or sweat. Is there something unsafe about the clays or is it just the potential mess that can occur using porous pottery?

I am all ears........

[coloradopu]

that is something only the specific potter can answer. in raku some of the glazes can be harmful as well as the clay. but with that said if the potter is making the pots to be used it stands to reason that he/she would not use any such harmful things. i suggest getting in touch with the potter who made your stuff and ask them what they used. i know there are some potters out there who do make pots for use in a way that supports the public health but there are some who make pots that were never intended to be used everyday.

hope this helps

[cupioneer]

I have heard conflicting information about these 2 wares and would like someone knowledgeable to set it straight for me.

Many people claim raku is not to be used for food or drink and that both raku and hagi are porous and will either leak or sweat. Is there something unsafe about the clays or is it just the potential mess that can occur using porous pottery?

I am all ears........

You're interested in pottery other than Banko and Mumyoi??

Raku is known to use lead in the glaze. I've never heard anything about Hagi containing lead or other hazardous substances.

[Oni]

My kuro raku might be unsafe??? I drink matcha from it, I read the glaze was made with kamogava riverstone ground into powder.

Is my raku toxic?

[olivierco]

Not by matcha brewing anyway.
Chamekke wrote about it here

http://www.teachat.com/viewtopic.php?t=5333

[Tead Off]

Merci, olivierco. This helps a lot.

No one answered the question of porosity using either raku or hagiyaki. Being primarily an Oolong tea drinker, tea is usually brewed hotter and probably winds up in the cup hotter than Japanese green tea. Would there be an issue of sweating with either yaki?

[Chip]

One of the endearing "features" of Hagi is the sweating. Usually it simply feels like slightly warm and comfortably moist. It feels good to the touch.

Sometimes a new Hagi will actually leak, of all the Hagi I have, only one has actually leaked. Usually this will stop with use, but if it continues, there are remedies for it.

[Geekgirl]

Click the image for more "sweating." IME, my hagi sweats just a bit when I first fill the cup, if I haven't soaked it for a few minutes first. It evaporates very quickly. I have one cup that leaked slightly through pores on the foot, but it no longer leaks. I had another small hagi teabowl that leaked moderately (it would make a small puddle if tea sat in it very long) but it has gradually changed, and now maybe it will leak a drop or two. My new hagiyaki chawan did not leak at all. I do recommend you use a chataku or cloth when using new hagiware.

[Chip]

The porousity is due mostly because of the very sandy clay that is used. The glaze also crackles. So yeah, it is going to be porous. Nobody is hiding this fact either. This is why I suppose the "7 changes of Hagi" occur.

[bonjiri]

greetings all

i'm not an expert on raku

my humble understanding

there are basically two kinds of 'raku'. first the japanese raku and the other is american raku

american raku is fired at a lower temperature usually around 1400-1800 fahrenheit or so. the glazes usually are not food safe and most of all the pieces are porous. liquid will pass thru.

japanese raku (like hiki dashi) is fired upwards to 2100-2277 degrees fahrenheit (orton cone 5 thru making the pot semi vitrified. vitrification happens when the air spaces seal off and it becomes water tight.

one point to see if the piece is vitrified, just flick the piece. if u hear a ring, chances are its vitrified. if u hear a thud, dead sound its likely its not vitrified. 'american raku' is usually low fired and also brittle. glazes are susceptible to oxidation and can change in color. i.e. copper red shiny raku can fade in time and lose its red color and turn greenish (patina).

one last thing. about glaze formulation/materials. in my own ceramic pieces, i'm very particular about all the glaze ingredients that makeup the glaze. i mix each component and know each item that goes in. i shy away from barium and manganese dioxide for functional/table ware. even in some frits/colorants being used there is lead contained in some of the frits (colorants). so caveat emptor. most of the shino, red iron, tenmoku, and white glazes are perfect for food ware. some red glazes contain some barium.

humbly

cory Lum

[chamekke]

Just a quick P.S. to Cory's excellent posting.

Japanese raku is considered safe when used for drinking matcha - in part because the matcha is consumed immediately after being prepared, and also because matcha is not acidic. However, from everything I've read or been told, even the (relatively safe) Japanese raku should not be used for foods - acidic foods in particular - because any "wet" consumable that sits in the dish for some time can leach out some of the lead, and is particularly likely to do so if it is acidic. This is why you don't typically see food vessels, such as mukouzuke, made from raku ... it is much more usual to see Shino etc. instead.

So, if you're going to use raku as a vessel for food or drink, make it Japanese raku, and make it a matcha chawan - or maybe a chaire, which is used for storing (dry) matcha powder, and even then only for a short time.

This is kind of repeating some of the stuff that was said in the Raku Lead Glaze Concern thread, but I do think it's important for people to know.