Lee Love on mon 5 apr 04
Ivor and Olive Lewis wrote:
>I do not recall inferring that Oribe glaze contains Boron. I told the
>group that some of the acids which might be used could deplete Boron
>bearing substances.
>
>
I've used boric acid eye wash and brought a boric acid ear powder
with me from America for my Akita Taiko. Must be really dilute.
>remove the lime deposits. Unless manufacturers wish to divulge the
>contents of their products who would know?
>
>
In America, they were listed on the label. Here in Japan, I
can't read the label so I can't tell.
I was listening to the owner of the 7th Generation on the radio
yesterday. He said that chlorine bleach was probably one of the most
hazardous chemicals in your average house. It mixes with all sorts of
common things to create dioxins. Don't mix it with ammonia, which is
in many kitchen and bathroom cleaners. Will burn your lungs out.
>Some beverages contain one of the Phosphoric acids, again you need to
>be party to the recipe to find out which. Acid in Japanese foods ? I
>thought Japanese culinary culture was famous for pickles, preserved in
>Sake Vinegar.
>
>
I think you are talking about mirin, rice vinegar. It is very mild and
sweet. I think of it more like cooking wine than vinegar, like back
home. I use it in cooking all the time. Chinese vinegar is more
acidic and stronger.
Lee http://mashiko.org
Jason Truesdell on mon 5 apr 04
Usually "o-su" is rice vinegar, which is less acidic than apple cider =
vinegar but is tart nonetheless. Mirin is a sweetened rice wine =
(sometimes sweetened diluted shochu).
Typically Japanese acidic dishes include su-no-mono (vinegared things, =
usually lightly sweetened; cucumber is common), and vinegar-type =
tsukemono (salt, miso, and nuka tsukemono develop acidity through =
fermentation as well). Since most foods are slightly acidic, it's =
probably possible for most foods to react with certain metal-based =
chemicals, but the reactivity should be very low except in cases like =
su-no-mono, tsukemono, or certain styles of o-hitashi.
I've never had much concern about food safety with my Japanese ceramic =
collection for reasons similar to yours; I figure that if people have =
usually been eating off of similar glazes for several hundred years or =
more that it can't be much risk to me with occasional use. I don't leave =
foods out on them for more than a few hours if it's a party, and much =
less in typical use. In Kyoto I was at a restaurant where the old woman =
who ran the place kept all of her prepped foods in ceramic bowls or =
plates... actually I bet they were even held longer at room temperature =
than the US health departments consider acceptable but I wasn't =
particularly worried about food safety either.
On the other hand, Japanese product liability laws are probably less =
favorable for injured parties and if someone could prove a connection =
between an illness and a pot I doubt they would feel like it was worth =
the trouble of suing or obtaining a financial remedy from the =
manufacturer. So US potters probably have even more cause for concern =
about the work they produce, especially if they have any notable =
production volume.
----- Original Message -----=20
From: Lee Love=20
To: CLAYART@LSV.CERAMICS.ORG=20
Sent: Monday, April 05, 2004 5:12 AM
Subject: Acid and Vinegar ; was: Foodsafe Oribe
Ivor and Olive Lewis wrote:
>I do not recall inferring that Oribe glaze contains Boron. I told the
>group that some of the acids which might be used could deplete Boron
>bearing substances.
>
>
I've used boric acid eye wash and brought a boric acid ear =
powder
with me from America for my Akita Taiko. Must be really dilute.
>remove the lime deposits. Unless manufacturers wish to divulge the
>contents of their products who would know?
>
>
In America, they were listed on the label. Here in Japan, I
can't read the label so I can't tell.
I was listening to the owner of the 7th Generation on the radio
yesterday. He said that chlorine bleach was probably one of the =
most
hazardous chemicals in your average house. It mixes with all sorts =
of
common things to create dioxins. Don't mix it with ammonia, which =
is
in many kitchen and bathroom cleaners. Will burn your lungs out.
>Some beverages contain one of the Phosphoric acids, again you need to
>be party to the recipe to find out which. Acid in Japanese foods ? I
>thought Japanese culinary culture was famous for pickles, preserved =
in
>Sake Vinegar.
>
>
I think you are talking about mirin, rice vinegar. It is very mild =
and
sweet. I think of it more like cooking wine than vinegar, like back
home. I use it in cooking all the time. Chinese vinegar is more
acidic and stronger.
Lee http://mashiko.org
=
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clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from =
http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at =
melpots@pclink.com.
Ivor and Olive Lewis on tue 6 apr 04
Dear Jason Truedell,
A good test for the level of acidity in any a food or food condiment
is to leave a real copper penny in it for a short while and then wash
the corrosive away. Which brings us around to the Ceramic reason for
this thread. Acidic liquids leach copper ions from a mature glaze.
Nor should we be mislead by the presence of a sweetening agent in any
condiment. Sugar is added to the recipe to reduce a high level of
tartness due to the acid. It does not neutralise acidity, or negate
the corrosive effects.
As an interesting aside which may throw some light onto this problem
of the stability of Copper in glaze, L. A. Lay, "Corrosion Resistance
of Technical Ceramics" indicates that Vitreous Silicates resist
attack by molten Copper Metal in a nitrogen atmosphere at 1210 =BA C.
Best regards,
Ivor Lewis. Redhill, South Australia
Ivor and Olive Lewis on tue 6 apr 04
Dear Lee Love,
All substances which are acids have the potential to corrode, that is
dissolve things that are basic or neutral. Many alkali substances are
also corrosive.
This goes for the acid in your stomach which contains and average of
3.65 grams per litre of Hydrogen Chloride. In your stomach you have
the protection of the mucous lining but if you regurgitate fluid from
your stomach your oesophagus will be burned by the acid and you will
experience some degree of pain.
I recently bought a carton of Boric (Boracic) Acid. On the label it
says clearly "CAUTION. DO NOT USE FOR MEDICAL PURPOSES" . I will heed
that warning and use it only for ceramic purposes. But I would not ill
treat my dog s with it, regardless of their breed.
Best regards,
Ivor Lewis. Redhill, South Australia
terryh on tue 6 apr 04
Lee wrote again,
>I think you are talking about mirin, rice vinegar.
>It is very mild and sweet.
"mirin" is not vinegar. mirin is thickened sweet
cooking wine. not desert wine like sautern.
(rice) vinegar is "su". rice vinegar is a little
sweeter compared to wine vinegar.
su and mirin are totally different.
if you don't taste the difference, you must be
smoking too much .
and i saw another post from lee who wrote,
>First question Terry, would you tell people not
>to use traditional Japanese pottery because of
>"food safety" reasons?
why this question? i'm pointing out lee's mis-conception
of japanese diet. there are many acidic japanese food.
japanese have been using japanese pottery for some time,
whether safe or not. i use mine every day.
also he wrote,
>Umeboshi are pickled with salt, not vinegar.
in my recollection, my mother and my grandmother used
lots and lots of sea salt and a little bit of vinegar to
cure umeboshi. so i was eating un-japanese umeboshi :)
i may be wrong about this, though: they may not have
added vinegar to cure umeboshi.
umeboshi may not be, but there are many pickles cured
with su (rice vinegar) and salt. quite contrary to
lee's experience, acidic food is very common in japanese
diet such as these "su-no-mono"s and japanese liking of
"pon-zu" dressing.
>The (umeboshi) juice is incorrectly called vinegar.
>Macrobiotics see this (=umeboshi) as an alkaline food
>and is used for stomach ailments like car sickness
>and the like because of this.
BS. the juice "ume-zu(su)" is strongly acidic.
as i wrote earlier, umeboshi in the aluminium lunchbox
was causing lots of problem because of its strong acidity.
and why quoting that umeboshi is alkaline food?
does making one's blood alkaline mean that umeboshi is
not acidic but alkaline food? i don't think eating salad
makes one's blood sour.
japanese used umeboshi to prevent food getting spoiled
(that's why an umeboshi in lunch box) because of its strong
acidity and high salt content. just like vinegar-cured fish
in steamed rice (the origin of sushi).
looks like this is getting out of clay topics, though food is
very much a clay subject (to me) :)
nit-picking terry
terry hagiwara
terryh@pdq.net
http://www.geocities.com/terry.hagiwara
Lee Love on tue 6 apr 04
Jason Truesdell wrote:
>I've never had much concern about food safety with my Japanese ceramic collection for reasons similar to yours; I figure that if people have usually been eating off of similar glazes for several hundred years or more that it can't be much risk to me with occasional use. I don't leave foods out on them for more than a few hours if it's a party, and much less in typical use. In Kyoto I was at a restaurant where the old woman who ran the place kept all of her prepped foods in ceramic bowls or plates... actually I bet they were even held longer at room temperature than the US health departments consider acceptable but I wasn't particularly worried about food safety either.
>
>
Thanks for the correction on the difference between vinegar and mirin.
Lee in Mashiko, Japan
surf with Lee: http://hachiko.com
Ivor and Olive Lewis on wed 7 apr 04
Dear Terryh,
You write <problem because of its strong acidity.>>
Why I do not know, but I failed to latch onto this when you first
mentioned it.
But aluminium oxide is amphoteric and is soluble in both strong acids
and strong alkalies, So is aluminium metal. Reacting aluminium powder
with Caustic Soda is one way to generate Hydrogen.
Best regards,
Ivor Lewis. Redhill, South Australia
Lee Love on wed 7 apr 04
terryh wrote:
>>First question Terry, would you tell people not
>>to use traditional Japanese pottery because of
>>"food safety" reasons?
>>
>>
>
>why this question?
>
>
Because this is what the topic has been. So I'll ask again: Does
the nature of traditional Japanese food keep you from using it on
traditional Japanese pottery? My Japanese mother's tastes in
pottery tended toward Noritake. :-)
>what I actually wrote Terry,
>
>
>>Umeboshi are pickled with salt, not vinegar.
>>
>>
>
>in my recollection, my mother and my grandmother used
>lots and lots of sea salt and a little bit of vinegar
>
Who is creating misinformation? Traditionally, Umeboshi is made
with salt. "A little" weak Japanese vinegar is probably not going to
effect the pH a great deal anyway. Ume plum is also pickled in miso.
At my teacher's workshop, we picked ume plums and Yoshiko (our teacher's
daughter) pickled them in sake, making ume shu. The plums are also
astringent when pickled in this manner. Shu-san, from Peking, liked
to crack the seeds open and eat them. These were very astringent.
>lee's experience, acidic food is very common in japanese
>diet such as these "su-no-mono"s and japanese liking of
>"pon-zu" dressing.
>
>
Japanese vinegar is very mild. I will look for a pH tester like the
one previously mentioned and test for you. So I stand by my statement
(or my wife's Jean's statement,) that Japanese food is not very acidic.
Salty and the fried food is greasy, but not And to make it relevant
to the current discussion, Zen and tea ceremony food tends to be even
less acidic that your average Japanese fare and stays in the container
for a much shorter time.
> <>BS. the juice "ume-zu(su)" is strongly acidic.
> as i wrote earlier, umeboshi in the aluminium lunchbox
>
BS? That's very intelligent. As Janet mentioned,
Alkali can be as corrosive as acid. I've searched the web and cannot
find the pH, only numerous mentioning of it being an alkali food,
prescribed for stomach acid and car sickness. It is true, in looking
at traditional nutrition, some foods which are acidic can make the body
alkali, but the "out of body" pH isn't always listed. I will test
Umeboshi and let you know what the pH is. Need to find litmus paper
or a pH tester.
Lee In Mashiko, Japan
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