When I steep chopped garlic pieces in Japanese rice vinegar for a few days,
they stay the same colour. When doing so in Tesco's Chinese rice vinegar
they turn bright green blue. What would be the likely difference in the two
vinegar's?

On Oct 25, 6:03*pm, "john royce" > wrote:
> When I steep chopped garlic pieces in Japanese rice vinegar for a few days,
> they stay the same colour. *When doing so in Tesco's Chinese rice vinegar
> they turn bright green blue. *What would be the likely difference in the two
> vinegar's?

Methanol

On Sun, 25 Oct 2009 09:03:29 -0000, john royce wrote:

> When I steep chopped garlic pieces in Japanese rice vinegar for a few days,
> they stay the same colour. When doing so in Tesco's Chinese rice vinegar
> they turn bright green blue. What would be the likely difference in the two
> vinegar's?

have you done this many times? the difference could be in the garlic:

The discoloration is due to pigments that form between sulfur compounds in
garlic and amino acids. When the garlic tissue is disrupted, as happens in
processing, an enzyme is liberated and reacts with it to form
thiosulfinates compounds that then react with the natural amino acids in
the garlic to form blue pigments. The age of garlic determines how much
isoalliin there is in the first place, and the nature of the processing
determines how much enzyme is liberated.

Original thoughts and ideas:

Garlic is known to contain sulfur compounds which can react with minute
traces of copper to form copper sulfate, a blue or blue-green compound. The
amount of copper needed for this reaction is very small and is frequently
found in normal water supplies. Raw garlic contains an enzyme that if not
inactivated by heating reacts with sulfur (in the garlic) and copper (from
water or utensils) to form blue copper sulfate. The garlic is still safe to
eat.

* If fresh garlic is picked before it is fully mature and hasn't been
properly dried, it can turn and iridescent blue or green color when in the
presence of an acid. It may be caused by an allinin derivative.

* A reaction between garlic's natural sulfur content and any copper
in your water supply, or in the cooking utensils your are using (such as
cast iron, tin, or aluminum) can sometimes change the color of garlic.

* The other sources of copper might be butter, lemon juice, or
vinegar.

* Garlic will also turn green (develop chlorophyll) if exposed to an
temperature change or is exposed to sunlight. Some people say it can be
stored for 32 days at or above 70 - 80° F to prevent greening (but I'm not
yet sure that is true).

* Are you using table salt instead of kosher or canning salt? That
can cause the garlic to turn blue or green. Table salt contains iodine,
which discolors whatever you're pickling. Use kosher or pickling salt.

* Different varieties or growing conditions can actually produce
garlic with an excess natural bluish/green pigmentation (anthocyanins*)
made more visible after pickling.

* Any of various water-soluble pigments that impart to flowers and
other plant parts colors ranging from violet and blue to most shades of
red. This pigment is produced after chlorophyll is destroyed due to
environmental changes. This is a variable phenomenon that is more
pronounced for immature garlic but can differ among cloves within a single
head of garlic. If you grow your own garlic, be sure to mature it at room
temperature for a couple of weeks before using it.

Don't worry, greenish-blue color changes aren't harmful and your garlic is
still safe to eat. (unless you see other signs of spoilage).

<http://whatscookingamerica.net/garlictips.htm>

your pal,
blake

"john royce" > wrote in message
...
> When I steep chopped garlic pieces in Japanese rice vinegar for a few
> days, they stay the same colour. When doing so in Tesco's Chinese rice
> vinegar they turn bright green blue. What would be the likely difference
> in the two vinegar's?
>
I was always told not to steep garlic in oil due to a possibility of
botulism-but I am not sure it applies to vinegar as well.

In article >,
"john royce" > wrote:

> When I steep chopped garlic pieces in Japanese rice vinegar for a few days,
> they stay the same colour. When doing so in Tesco's Chinese rice vinegar
> they turn bright green blue. What would be the likely difference in the two
> vinegar's?

The garlic. It happens sometimes.


--
-Barb, Mother Superior, HOSSSPoJ
http://web.me.com/barbschaller - Yes, I Can! blog
Welcoming the arrival of Emma Kathryn on 10-22-09;
she is great-grand-niece/-nephew #8.

In article >,
"Kswck" > wrote:

> "john royce" > wrote in message
> ...
> > When I steep chopped garlic pieces in Japanese rice vinegar for a few
> > days, they stay the same colour. When doing so in Tesco's Chinese rice
> > vinegar they turn bright green blue. What would be the likely difference
> > in the two vinegar's?
> >
> I was always told not to steep garlic in oil due to a possibility of
> botulism-but I am not sure it applies to vinegar as well.

You can put most anything in vinegar, Keith. :-)
People do it to cucumbers all the time. :-)
--
-Barb, Mother Superior, HOSSSPoJ
http://web.me.com/barbschaller - Yes, I Can! blog
Welcoming the arrival of Emma Kathryn on 10-22-09;
she is great-grand-niece/-nephew #8.

>"john royce" > wrote in message
...
>> When I steep chopped garlic pieces in Japanese rice vinegar for a few
>> days, they stay the same colour. When doing so in Tesco's Chinese rice
>> vinegar they turn bright green blue. What would be the likely difference
>> in the two vinegar's?

The colour change is a reaction between the garlic's natural sulphur
content and copper. It's likely that Tesco's vinegar contains traces
of copper or a copper compound while the Japanese vinegar does not.
The garlic is still safe to eat.

Ross

On Oct 25, 5:00*pm, Melba's Jammin' >
wrote:
> In article >,
>
> *"Kswck" > wrote:
> > "john royce" > wrote in message
> ...
> > > When I steep chopped garlic pieces in Japanese rice vinegar for a few
> > > days, they stay the same colour. *When doing so in Tesco's Chinese rice
> > > vinegar they turn bright green blue. *What would be the likely difference
> > > in the two vinegar's?
>
> > I was always told not to steep garlic in oil due to a possibility of
> > botulism-but I am not sure it applies to vinegar as well.
>
> You can put most anything in vinegar, Keith. *:-)
> People do it to cucumbers all the time. *:-)

I'm sure several rfc-ers do it to themselves.

I think it's time for a beer.

John Kane, Kingston ON Canada

Kswck wrote:
>
> "john royce" > wrote in message
> ...
> > When I steep chopped garlic pieces in Japanese rice vinegar for a few
> > days, they stay the same colour. When doing so in Tesco's Chinese rice
> > vinegar they turn bright green blue. What would be the likely difference
> > in the two vinegar's?
> >
> I was always told not to steep garlic in oil due to a possibility of
> botulism-but I am not sure it applies to vinegar as well.

It doesn't. Oil cuts off access to oxygen,
which allows poisonous anaerobic bacteria
to grow. Vinegar doesn't do that.

On Sun, 25 Oct 2009 13:20:09 -0800, Mark Thorson >
wrote:

>Kswck wrote:
>>
>> "john royce" > wrote in message
>> ...
>> > When I steep chopped garlic pieces in Japanese rice vinegar for a few
>> > days, they stay the same colour. When doing so in Tesco's Chinese rice
>> > vinegar they turn bright green blue. What would be the likely difference
>> > in the two vinegar's?
>> >
>> I was always told not to steep garlic in oil due to a possibility of
>> botulism-but I am not sure it applies to vinegar as well.
>
>It doesn't. Oil cuts off access to oxygen,
>which allows poisonous anaerobic bacteria
>to grow. Vinegar doesn't do that.

As I understand it, steeping fresh garlic in vinegar does prevent the
growth of Clostridium botulinum spores but, not because it is an
anaerobic environment.
Conditions that favour the production of botulism toxin are, high
humidity, low salt, low acid and lack of oxygen.
Steeping fresh garlic in oil provides all these conditions.
Steeping in vinegar effectively eliminates the low acid requirement.

Ross.

john royce wrote:
>
> When I steep chopped garlic pieces in Japanese rice vinegar for a few days,
> they stay the same colour. When doing so in Tesco's Chinese rice vinegar
> they turn bright green blue. What would be the likely difference in the two
> vinegar's?

Is the Chinese rice vinegar more acidic than the Japanese product?

On Sun, 25 Oct 2009 15:34:19 -0400, Kswck wrote:

> "john royce" > wrote in message
> ...
>> When I steep chopped garlic pieces in Japanese rice vinegar for a few
>> days, they stay the same colour. When doing so in Tesco's Chinese rice
>> vinegar they turn bright green blue. What would be the likely difference
>> in the two vinegar's?
>>
> I was always told not to steep garlic in oil due to a possibility of
> botulism-but I am not sure it applies to vinegar as well.

it doesn't. oil makes for an anaerobic environment while vinegar does not.

your pal,
blake

On Sun, 25 Oct 2009 09:26:52 -0400, blake murphy
> wrote:

>On Sun, 25 Oct 2009 09:03:29 -0000, john royce wrote:
[snipped]

>have you done this many times? the difference could be in the garlic:
>
> The discoloration is due to pigments that form between sulfur compounds in
>garlic and amino acids. When the garlic tissue is disrupted, as happens in
>processing, an enzyme is liberated and reacts with it to form
>thiosulfinates compounds that then react with the natural amino acids in
>the garlic to form blue pigments. The age of garlic determines how much
>isoalliin there is in the first place, and the nature of the processing
>determines how much enzyme is liberated.
>
>Original thoughts and ideas:
>
>Garlic is known to contain sulfur compounds which can react with minute
>traces of copper to form copper sulfate, a blue or blue-green compound. The
>amount of copper needed for this reaction is very small and is frequently
>found in normal water supplies. Raw garlic contains an enzyme that if not
>inactivated by heating reacts with sulfur (in the garlic) and copper (from
>water or utensils) to form blue copper sulfate. The garlic is still safe to
>eat.

{more snipped}

This is indeed a difficult question, as the number of variables is
great. FE: What Blake says is correct. It follows that the two
vinegars may be been manufactured in different vessels, and
you have no control over that. Also, natural vinegar is made
in wood or crockery, from (wait for it....) RICE! Some can
be made by a bulk process using a mash or concentrate
that *contains* rice, along with other stuff. An innocuous
example is OJ (made from concentrate in a factory). Some
soy sauces do NOT use soybeans as a starting material.
FOr that reason, there are lawsuits in existence to force
labelling of "Soy Sauces" made from anything other
than natural soybeans in their natural state.

I use Marukan or other Japanese vinegars exclusively when
I need rice vinegar. If I'm out I use cane vinegar from the
Philippine Islands, either the Sarap brand or White Swan,
which I suspect are made at the same facility.

I do NOT feel comfortable with most CHinese products
unknown to me, although I've had good luck (I ain't dead
yet) with ShaoTsing (AKA TsingChao) cooking wine.

For all you know, one of your vinegars may have been made
in copper vessels, with lead or tin solder, rather than in food
grade S/S.

Good luck

Alex