I often read that the k-meta contain 57% sulphite and the campden
tablets 48%. I would like a clarification on that.

A) Is the 57% mean the % of sulphite contain in a given amount of
k-meta from wich you will get some bound SO2 and free SO2

OR

B) The 57% mean that from any given amount of k-meta added you will
roughly get 57% of free SO2 ( theorical of course )

Thanks for your explanations

Séb

On 5/6/04 9:51 PM, in article
, "seb"
> wrote:

> I often read that the k-meta contain 57% sulphite and the campden
> tablets 48%. I would like a clarification on that.
>
> A) Is the 57% mean the % of sulphite contain in a given amount of
> k-meta from wich you will get some bound SO2 and free SO2
>
> OR
>
> B) The 57% mean that from any given amount of k-meta added you will
> roughly get 57% of free SO2 ( theorical of course )
>
> Thanks for your explanations
>
> Séb

I believe it is 57% of the weight of the K-meta will be SO2. Campden has
other "inert" binders added to it to hold the tablet shape, so it has more
other stuff per gram than pure K-meta. Also, Isn't campden tablets
sodium-meta and not K-meta ?

--
Greg Cook
http://homepage.mac.com/gregcook/Wine
http://homepage.mac.com/gregcook/aws

(remove spamblocker from my email)

> I often read that the k-meta contain 57% sulphite and the campden
> tablets 48%. I would like a clarification on that.

K-meta is about 58% SO2.

Campden tablets are designed to have about 0.44 grams of (often K-)
meta. Whether they are 48% SO2 or not really depends on the tablet
size, which tends to vary depending on the manufacturing process.

> B) The 57% mean that from any given amount of k-meta added you will
> roughly get 57% of free SO2 ( theorical of course )

It means you'll get ~58% *total* SO2. Some of that will then become
free, and some will become bound (total = bound + free).

See http://members.tripod.com/~BRotter/SO2.htm for more.

Ben

Ben Rotter ) wrote:
>> I often read that the k-meta contain 57% sulphite and the campden
>> tablets 48%. I would like a clarification on that.

>K-meta is about 58% SO2.

>Campden tablets are designed to have about 0.44 grams of (often K-)
>meta. Whether they are 48% SO2 or not really depends on the tablet
>size, which tends to vary depending on the manufacturing process.
>
>> B) The 57% mean that from any given amount of k-meta added you will
>> roughly get 57% of free SO2 ( theorical of course )

>It means you'll get ~58% *total* SO2. Some of that will then become
>free, and some will become bound (total = bound + free).

>See http://members.tripod.com/~BRotter/SO2.htm for more.

>Ben

And FWIW, when I've "standardized" bags of meta, I've found actual
levels more like 36%.

And it'd be less if you use hot water or water with chlorine (so
I've been told--does anyone know for sure if chlorine reacts with
SO2) to dissolve your meta.

Dave
************************************************** **************************
Dave Breeden

Greg Cook > wrote in message ws.com>...
>
> I believe it is 57% of the weight of the K-meta will be SO2. Campden has
> other "inert" binders added to it to hold the tablet shape, so it has more
> other stuff per gram than pure K-meta. Also, Isn't campden tablets
> sodium-meta and not K-meta ?


Greg, you can find campden in the form of k-meta too.

(Ben Rotter) wrote in message . com>...

> It means you'll get ~58% *total* SO2. Some of that will then become
> free, and some will become bound (total = bound + free).

Ben, here a quote from the winemakermag :

"The key question now is: How much free SO2 is really added for any
given amount of sulfite? Potassium metabisulfite and Campden tablets
consist of approximately 57 percent and 48 percent SO2, respectively.
This means that roughly half of the sulfite actually becomes free SO2
when a solution is prepared and added to wine."

Thanks for your link, I had already read it and many more about SO2
but I read different things about the 57% explanation. That's the
only part i can't be sure of.

Séb

seb ) wrote:
(Ben Rotter) wrote in message . com>...
>
>> It means you'll get ~58% *total* SO2. Some of that will then become
>> free, and some will become bound (total = bound + free).

>Ben, here a quote from the winemakermag :

>"The key question now is: How much free SO2 is really added for any
>given amount of sulfite? Potassium metabisulfite and Campden tablets
>consist of approximately 57 percent and 48 percent SO2, respectively.
>This means that roughly half of the sulfite actually becomes free SO2
>when a solution is prepared and added to wine."

>Thanks for your link, I had already read it and many more about SO2
>but I read different things about the 57% explanation. That's the
>only part i can't be sure of.

>Séb

Hi,

It's easy enough to calculate for yourself. Meta is just K2S2O5,
and the molecular weights of K, S, and O are 39, 32, and 16,
repsectively. Find the total weight, and divide it into the weight
of the 2 SO2 molecules you get from each meta molecule.

Voila! 57%.

:-)

Dave
************************************************** **************************
Dave Breeden

Man has been adding sulfur dioxide to wine for more than a thousand
years. A
large body of knowledge exists on the use of sulfur dioxide in wine
and in many
other food products. The benefits of using sulfur dioxide are well
documented,
and its positive effects are indisputable.

I think your reference to time may be somewhat exaggerated. It's
positive effects are also relative to what you want to obtain. For
most home-made wine makers you will find that they generally do not
store their wines for more than 3-4 years. They keep it stored usually
under constant conditions and in a fairly cool cellar (10 - 15 C). And
they are fairly hygienic in the way they work with the must and wine
(compared to commercial production).

There is a minimum of risk w.r.t. spoiling the wine under such
circumstances. The SO2 mania is something which have caught on by home
wine makers, not because of an experienced problem, but rather because
there is a belief that they need to take on all the practices of
commercial wineries.




(Ben Rotter) wrote in message . com>...
> > I often read that the k-meta contain 57% sulphite and the campden
> > tablets 48%. I would like a clarification on that.
>
> K-meta is about 58% SO2.
>
> Campden tablets are designed to have about 0.44 grams of (often K-)
> meta. Whether they are 48% SO2 or not really depends on the tablet
> size, which tends to vary depending on the manufacturing process.
>
> > B) The 57% mean that from any given amount of k-meta added you will
> > roughly get 57% of free SO2 ( theorical of course )
>
> It means you'll get ~58% *total* SO2. Some of that will then become
> free, and some will become bound (total = bound + free).
>
> See http://members.tripod.com/~BRotter/SO2.htm for more.
>
> Ben

David C Breeden wrote "Ben-And FWIW, when I've "standardized" bags of meta,
I've found actual levels more like 36%. And it'd be less if you use hot
water or water with chlorine (so I've been told--does anyone know for sure
if chlorine reacts with SO2) to dissolve your meta."

David and others interested in SO2 reactions.
Here is an excerpt from an article on the subject. A.J.DeLange is a well
known scientist in beer brewing circles. A lot of beer makers use K Meta to
rid local water of chlorine and chloramine.

bill frazier
olathe, kansas usa

Date: Tue, 08 Apr 2003 14:25:19 +0000From: "A.J. deLange" <ajdel at
cox.net>Subject: Chloramine/ZincFor Doug: The reaction between chlorine and
bisulfite is:S2O5-2 + 4Cl + 3H2O --> 2SO4-2 + 6H+ + 4 Cl-With mono
chloramine it is:S2O5-2 + 2H2NCl + 3H2O --> 2SO4-2 + 2H+ + 2Cl- + 2NH4+In
either case the bisulfite is oxidized to sulfate and the clorine, while it
is not "removed", is reduced to chloride ion.This method of removing
chlorine has been used by aquarists for years (though they use thiosulfate
rather than bisulfite). With the advent of chloramine they must be sure to
have an effective means of removing the ammonium ion/ammonia that is
produced. It's a simple thing to check out. Draw a glass of stinky
chlorinated or chloraminated water and drop in the corner of a Campden
tablet. The chlorine smell will be gone very quickly (to be replaced,
perhaps, with a sulfur dioxide smell so only use the tiniest bit of the
tablet - one tablet should treat 40 gallons of water containing 3 mg/L
chloramine.

David C Breeden wrote "And FWIW, when I've "standardized" bags of meta, I've
found actual
> levels more like 36%."
David and others...I'm sure you know that K Meta degrades rather
significantly over a years time. I buy fresh every year because of
this...it's inexpensive and you have a better chance of adding the correct
amount of SO2.

bill frazier
olathe, kansas usa

(seb) wrote in message . com>...
> (Ben Rotter) wrote in message . com>...
>
> > It means you'll get ~58% *total* SO2. Some of that will then become
> > free, and some will become bound (total = bound + free).
>
> Ben, here a quote from the winemakermag :
>
> "The key question now is: How much free SO2 is really added for any
> given amount of sulfite? Potassium metabisulfite and Campden tablets
> consist of approximately 57 percent and 48 percent SO2, respectively.
> This means that roughly half of the sulfite actually becomes free SO2
> when a solution is prepared and added to wine."
>
> Thanks for your link, I had already read it and many more about SO2
> but I read different things about the 57% explanation. That's the
> only part i can't be sure of.

If you read the section titled "3. Sodium and Potassium Salts" you'll
see why K meta is quoted as 57% SO2. Potassium metabisulphite has the
chemical formula K2S2O5 and a molecular weight of 222.4, and sulphur
dioxide has the chemical formula SO2 and a molecular weight of 64.1.
Each mole of the potassium meta salt will give 2 moles of SO2, thus
the SO2 content of K meta is 2 x 64.1/222.4 = 57.6%.

This, of course, is the theoretical maximum SO2 yield from K meta. In
practise, it can be lower as Dave has mentioned.

Dave: I've had similar experiences as you have with the strength of my
meta. It just depends on the supplier (i.e. how it's been stored,
etc). These days I always check my SO2 stock solutions to make sure
they're up to strength.

Ben

On 5/7/04 10:06 AM, in article , "David C
Breeden" > wrote:

> seb ) wrote:
>> (Ben Rotter) wrote in message
>> . com>...
>>
>>> It means you'll get ~58% *total* SO2. Some of that will then become
>>> free, and some will become bound (total = bound + free).
>
>> Ben, here a quote from the winemakermag :
>
>> "The key question now is: How much free SO2 is really added for any
>> given amount of sulfite? Potassium metabisulfite and Campden tablets
>> consist of approximately 57 percent and 48 percent SO2, respectively.
>> This means that roughly half of the sulfite actually becomes free SO2
>> when a solution is prepared and added to wine."
>
>> Thanks for your link, I had already read it and many more about SO2
>> but I read different things about the 57% explanation. That's the
>> only part i can't be sure of.
>
>> Séb
>
> Hi,
>
> It's easy enough to calculate for yourself. Meta is just K2S2O5,
> and the molecular weights of K, S, and O are 39, 32, and 16,
> repsectively. Find the total weight, and divide it into the weight
> of the 2 SO2 molecules you get from each meta molecule.
>
> Voila! 57%.
>
> :-)
>
> Dave
> ************************************************** **************************
> Dave Breeden


That's exactly right. But that would be TOTAL SO2 - not free SO2. Some will
still be bound as sulfite. The free SO2 will be dependant on the pH of the
wine. So I guess 57% would be more like a "potential" SO2 rather than the
actual free SO2 in solution.
--
Greg Cook
http://homepage.mac.com/gregcook/Wine
http://homepage.mac.com/gregcook/aws

(remove spamblocker from my email)

"seb" > wrote in message
m...
> I often read that the k-meta contain 57% sulphite and the campden
> tablets 48%. I would like a clarification on that.
>
> A) Is the 57% mean the % of sulphite contain in a given amount of
> k-meta from wich you will get some bound SO2 and free SO2
>
> OR
>
> B) The 57% mean that from any given amount of k-meta added you will
> roughly get 57% of free SO2 ( theorical of course )

Not quite either of A or B, but B is closer.

BTW, forget about Campden tablets if you do any serious amount of
winemaking. Buy meta in bulk and weigh it out yourself. You need a balance
with an accuracy of 0.1 g or better. You also need to reseal the meta
really well or it'll go dead on you.

K2S2O5 - straight out of a bag from the manufacturer - usually assays ~50%,
±2% available SO2. The stuff is very reactive to air - especially moist
air. By the time you get it the assay will be ~50% if you got a good batch.
Remember that part where I said to reseal the meta really well? I meant it.
Solutions don't last too long either. Make fresh if you're adding it to
your wine.

If you use this in a wine that has not been previously sulfited the free SO2
when you're done will be as if you used stuff that was only ~25%. A portion
of the sulfite becomes _bound_ in the wine.

Once the requirement for bound sulfite has been met, whatever you add beyond
that adds directly to the free SO2. That makes late adjustments really
easy - assuming you know the pH (which is what determines your target free
SO2).

This topic is not easy to grasp in its entirety, but it's very important to
know about the 0.8 ppm molecular free SO2 requirement and its interrelation
with pH and free SO2.

Tom S

"Greg Cook" > wrote in message
s.com...
> On 5/7/04 10:06 AM, in article , "David C
> Breeden" > wrote:
>
> > seb ) wrote:
> >> (Ben Rotter) wrote in message
> >> . com>...
> >>
> >>> It means you'll get ~58% *total* SO2. Some of that will then become
> >>> free, and some will become bound (total = bound + free).
> >
> >> Ben, here a quote from the winemakermag :
> >
> >> "The key question now is: How much free SO2 is really added for any
> >> given amount of sulfite? Potassium metabisulfite and Campden tablets
> >> consist of approximately 57 percent and 48 percent SO2, respectively.
> >> This means that roughly half of the sulfite actually becomes free SO2
> >> when a solution is prepared and added to wine."
> >
> >> Thanks for your link, I had already read it and many more about SO2
> >> but I read different things about the 57% explanation. That's the
> >> only part i can't be sure of.
> >
> >> Séb
> >
> > Hi,
> >
> > It's easy enough to calculate for yourself. Meta is just K2S2O5,
> > and the molecular weights of K, S, and O are 39, 32, and 16,
> > repsectively. Find the total weight, and divide it into the weight
> > of the 2 SO2 molecules you get from each meta molecule.
> >
> > Voila! 57%.
> >
> > :-)
> >
> > Dave
> >
************************************************** **************************
> > Dave Breeden

>
>
> That's exactly right. But that would be TOTAL SO2 - not free SO2. Some
will
> still be bound as sulfite. The free SO2 will be dependant on the pH of the
> wine. So I guess 57% would be more like a "potential" SO2 rather than the
> actual free SO2 in solution.
> --
> Greg Cook
> http://homepage.mac.com/gregcook/Wine
> http://homepage.mac.com/gregcook/aws
>
> (remove spamblocker from my email)
>

It is only a measure of the chemical content of the medium. It is your
known starting point. As they say, "Settling may occur during shipment."
and the old standby, "Your results may vary." :-)

Dad has been making wine for thirty plus years, and I don't think he even
knows what SO2 is, or cares.

Fred

"K.J.Kristiansen" > wrote in message
om...
> Man has been adding sulfur dioxide to wine for more than a thousand
> years. A
> large body of knowledge exists on the use of sulfur dioxide in wine
> and in many
> other food products. The benefits of using sulfur dioxide are well
> documented,
> and its positive effects are indisputable.
>
> I think your reference to time may be somewhat exaggerated. It's
> positive effects are also relative to what you want to obtain. For
> most home-made wine makers you will find that they generally do not
> store their wines for more than 3-4 years. They keep it stored usually
> under constant conditions and in a fairly cool cellar (10 - 15 C). And
> they are fairly hygienic in the way they work with the must and wine
> (compared to commercial production).
>
> There is a minimum of risk w.r.t. spoiling the wine under such
> circumstances. The SO2 mania is something which have caught on by home
> wine makers, not because of an experienced problem, but rather because
> there is a belief that they need to take on all the practices of
> commercial wineries.
>
>
>
>
> (Ben Rotter) wrote in message
. com>...
> > > I often read that the k-meta contain 57% sulphite and the campden
> > > tablets 48%. I would like a clarification on that.
> >
> > K-meta is about 58% SO2.
> >
> > Campden tablets are designed to have about 0.44 grams of (often K-)
> > meta. Whether they are 48% SO2 or not really depends on the tablet
> > size, which tends to vary depending on the manufacturing process.
> >
> > > B) The 57% mean that from any given amount of k-meta added you will
> > > roughly get 57% of free SO2 ( theorical of course )
> >
> > It means you'll get ~58% *total* SO2. Some of that will then become
> > free, and some will become bound (total = bound + free).
> >
> > See http://members.tripod.com/~BRotter/SO2.htm for more.
> >
> > Ben

Greg Cook ) wrote:
>On 5/7/04 10:06 AM, in article , "David C
>Breeden" > wrote:

>> seb ) wrote:
>>> (Ben Rotter) wrote in message
>>> . com>...
>>>
>>>> It means you'll get ~58% *total* SO2. Some of that will then become
>>>> free, and some will become bound (total = bound + free).
>>
>>> Ben, here a quote from the winemakermag :
>>
>>> "The key question now is: How much free SO2 is really added for any
>>> given amount of sulfite? Potassium metabisulfite and Campden tablets
>>> consist of approximately 57 percent and 48 percent SO2, respectively.
>>> This means that roughly half of the sulfite actually becomes free SO2
>>> when a solution is prepared and added to wine."
>>
>>> Thanks for your link, I had already read it and many more about SO2
>>> but I read different things about the 57% explanation. That's the
>>> only part i can't be sure of.
>>
>>> Séb
>>
>> Hi,
>>
>> It's easy enough to calculate for yourself. Meta is just K2S2O5,
>> and the molecular weights of K, S, and O are 39, 32, and 16,
>> repsectively. Find the total weight, and divide it into the weight
>> of the 2 SO2 molecules you get from each meta molecule.
>>
>> Voila! 57%.
>>
>> :-)
>>
>> Dave
>> ************************************************** **************************
>> Dave Breeden


>That's exactly right. But that would be TOTAL SO2 - not free SO2. Some will
>still be bound as sulfite. The free SO2 will be dependant on the pH of the
>wine. So I guess 57% would be more like a "potential" SO2 rather than the
>actual free SO2 in solution.
>--
>Greg Cook

Depends on what your solution is. :-)

In water, it's really (theoretically) 57%.

But yeah, the figure I gave was just the theoretical chemical
yield.

Dave
************************************************** **************************
Dave Breeden

Thanks, Bill! That's really very useful!

Dave

William Frazier ) wrote:

>David C Breeden wrote "Ben-And FWIW, when I've "standardized" bags of meta,
>I've found actual levels more like 36%. And it'd be less if you use hot
>water or water with chlorine (so I've been told--does anyone know for sure
>if chlorine reacts with SO2) to dissolve your meta."

>David and others interested in SO2 reactions.
>Here is an excerpt from an article on the subject. A.J.DeLange is a well
>known scientist in beer brewing circles. A lot of beer makers use K Meta to
>rid local water of chlorine and chloramine.

>bill frazier
>olathe, kansas usa

>Date: Tue, 08 Apr 2003 14:25:19 +0000From: "A.J. deLange" <ajdel at
>cox.net>Subject: Chloramine/ZincFor Doug: The reaction between chlorine and
>bisulfite is:S2O5-2 + 4Cl + 3H2O --> 2SO4-2 + 6H+ + 4 Cl-With mono
>chloramine it is:S2O5-2 + 2H2NCl + 3H2O --> 2SO4-2 + 2H+ + 2Cl- + 2NH4+In
>either case the bisulfite is oxidized to sulfate and the clorine, while it
>is not "removed", is reduced to chloride ion.This method of removing
>chlorine has been used by aquarists for years (though they use thiosulfate
>rather than bisulfite). With the advent of chloramine they must be sure to
>have an effective means of removing the ammonium ion/ammonia that is
>produced. It's a simple thing to check out. Draw a glass of stinky
>chlorinated or chloraminated water and drop in the corner of a Campden
>tablet. The chlorine smell will be gone very quickly (to be replaced,
>perhaps, with a sulfur dioxide smell so only use the tiniest bit of the
>tablet - one tablet should treat 40 gallons of water containing 3 mg/L
>chloramine.



--
Dave
************************************************** **************************
Dave Breeden