Sodium metabisulphite stock solution
CiderHead
concerns a quote from one of his web pages (requoted from a previous
thread where this subject came up):-
"It's often easier to use a stock solution of sulphur dioxide. To make
a
5% stock solution, dissolve around 10 grams of sodium or potassium
metabisulphite in 100 ml of water. (The metabisulphite salts contain
around 50 - 60% of available SO2 depending on how they've been
stored).
Then 1 ml of this per litre of juice (5 ml per gallon) corresponds
to
50 ppm (parts per million) of SO2."
So, according to the above, 100g in 1 litre makes a 5% stock solution.
However, my Vigo supplied product says "390g... in 5 litres will give
a a solution containing approximately 5% SO2".
There seems to be 3.9-fold diffreence between the two statements
unless I'm missing some thing here (that wouldn't surprise me!). Is
there an explanation for this discrepancy?
Thanks in advance,
Martin
greg l.
stronger than potassium and you don't say which one vigo is referring
to. The difference between 390g and 500g is not all that great.
Greg
CiderHead
On Oct 31, 9:40 pm, "greg l." <breadandbuttercr...@gmail.com> wrote:
> There is a difference in metabisulphite salts, sodium is slightly
> stronger than potassium and you don't say which one vigo is referring
> to. The difference between 390g and 500g is not all that great.
>
The difference is between 100g and 390g which is a big diffreence.
Andrew Lea
for *one* litre; Vigo's is for *five* litres.
Andrew
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Cider Workshop Website
www.ciderworkshop.com
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www.cider.org.uk
CiderHead
Andrew Lea
a worst case scenario - tired old metabisulphite and a solution that
hangs around for a bit. Vigo's calculation assumes a full stoichiometric
yield of SO2 by formula calculation and a solution that is used fairly
smartly. There is no easy way to tell the actual strength without doing
eg an iodine titration. You pays yer money and takes yer choice!
The metabisulphite salts are unstable and lose SO2 on ageing and do not
necessarily give the stoichiometric yield of SO2 even when fresh. They
are not as chemically defined as the textbooks would have you believe!
Fortunately an error even of 20% is not as bad as it seems, given all
the other assumptions that surround SO2 dosage (e.g. amount of binding,
individual microbial sensitivity etc etc).
Andrew
greg l.
Andrew's simplified stock solution is very useful, as are camden
tablets. Wineries are usually using fresh metabisulphite and want to
be as economical and accurate as possible, so they use the conversion
factor of 0.56 for PMS. But they always test for free SO2 before
bottling, and they still sometimes make mistakes. Following murphy's
law, it's always better to use procedures that will eliminate mistakes
before they happen.
Greg
CarlLeClair
procedures on dossing. I do feel more confident with your book at
hand Andrew, yet as I have been reading about the pH strips and
their variability adding to the problem we could in fact be way off on
our assumed dossing requirements, in addition to what is being
discussed here?
If Santa Claus is good to me this year I have on the top of my list
one
of these. At least I should have a good idea as to what I have done to
my cider with this unit?
http://www.midwestsupplies.com/vinmetrica-so2-analyzer-kit.html
Any comments on this item and what everyone is using to check the
SO2 levels of their cider would be interesting to hear of?
Regards,
Carl
Andrew Lea
> This is a timely subject as I have been concerned about my own
> procedures on dossing. I do feel more confident with your book at
> hand Andrew, yet as I have been reading about the pH strips and
> their variability adding to the problem we could in fact be way off on
> our assumed dossing requirements, in addition to what is being
> discussed here?
I'm afraid there are several sources of variation when SO2 dosing:
1. Accuracy of stock solution
2. Accuracy of pH determination
3. Unknown SO2 binding power of specific juice or cider
4. Unknown SO2 sensitivity of hostile organisms in your particular juice
Fortunately, experience shows that good results for craft cidermaking
can still be obtained within fairly wide limits even when these things
are not 'spot on'. So I don't think it pays to worry too much.
>
> If Santa Claus is good to me this year I have on the top of my list
> one
> of these. At least I should have a good idea as to what I have done to
> my cider with this unit?
>
> http://www.midwestsupplies.com/vinmetrica-so2-analyzer-kit.html
>
> Any comments on this item and what everyone is using to check the
> SO2 levels of their cider would be interesting to hear of?
Frankly I think Santa Claus should save his money! This seems a
terribly costly way of doing a simple Ripper titration (I'm sure you can
get good value Ripper kits in the USA). Also, on the face of it, it only
measures free SO2 not total, though it could probably be adapted for
total. With cider the starch / iodine end point is fairly easy to see.
With red wines there is admittedly an issue but with ciders there isn't,
so I can't see the value of an electrode system. Just more to go wrong!
I never check my SO2 (free or total). I know what I add and why I add it
and that's good enough for me. If I were in business I might, just for
reassurance and for 'due diligence' paperwork, but otherwise I go by
'rule of thumb'. Hope that doesn't shock you! But if you do need checks
of free or total SO2 on a craft basis, then a simple Ripper titration
should suffice.
BTW there is a fantastic online essay on all technical aspects of SO2 in
winemaking here http://www.brsquared.org/wine/Articles/SO2/SO2.htm but
it is very heavy going!!
Andrew
CarlLeClair
> > If Santa Claus is good to me this year I have on the top of my list
> terribly costly way of doing a simple Ripper titration (I'm sure you can
> get good value Ripper kits in the USA). Also, on the face of it, it only
> measures free SO2 not total, though it could probably be adapted for
> total. With cider the starch / iodine end point is fairly easy to see.
> With red wines there is admittedly an issue but with ciders there isn't,
> so I can't see the value of an electrode system. Just more to go wrong!
> I never check my SO2 (free or total). I know what I add and why I add it
> and that's good enough for me. If I were in business I might, just for
> reassurance and for 'due diligence' paperwork, but otherwise I go by
> 'rule of thumb'. Hope that doesn't shock you! But if you do need checks
> of free or total SO2 on a craft basis, then a simple Ripper titration
> should suffice.
experience,
Yet Professor Barker may have been shocked to hear of this ;)
> BTW there is a fantastic online essay on all technical aspects of SO2 in
> winemaking herehttp://www.brsquared.org/wine/Articles/SO2/SO2.htmbut
> it is very heavy going!!
>
> Andrew
Hoping my printer will survive this, as I know the ink will not :)
Best Regards,
Carl
Andrew Lea
>
>
>
>> I never check my SO2 (free or total). I know what I add and why I add it
>> and that's good enough for me. If I were in business I might, just for
>> reassurance and for 'due diligence' paperwork, but otherwise I go by
>> 'rule of thumb'. Hope that doesn't shock you! But if you do need checks
>> of free or total SO2 on a craft basis, then a simple Ripper titration
>> should suffice.
>
> It doesn't shock me in the least, with all your education and
> experience,
> Yet Professor Barker may have been shocked to hear of this ;)
Oddly enough, not so! Of course I never knew Bertie Barker since he had
retired and died long before I got to Long Ashton. But he did not
himself see much value in SO2 for cider making, except perhaps on
storage. AFAIR he had tried it experimentally but only obtained erratic
and unpredictable results, hence his viewpoint. The problem was that in
his day the pH dependency of SO2 action was not understood, and the
balance between the inactive ionic and the active molecular form was
totally unknown. It was not until Beech and Burroughs took another look
at SO2 in the 60's that the story became clearer and really wasn't fully
explained and rationalised until the 1970's. I joined Long Ashton at
that time, in my young and impressionable years, which is why I am such
an advocate for SO2 now!
On the other hand, to give him his due, it was Barker who pretty much
invented the Campden tablet (though he started with the Campden
solution). It was introduced for the cold sterile bottling of fruit, not
for wine or cider making. The idea was that high dose SO2 (ca 1000 ppm)
was used as a preservative so that heat was not required. Of course you
didn't eat the fruit with all that sulphite in it! You had to cook it to
drive off the SO2. It never really caught on for home preservation
(people preferred to heat sterilise and vacuum seal in bottling jars)
but for a while it was used in the jam industry to store gluts of fruit.
The Campden solution was replaced for home use by the Campden tablet
which now lives on in another life. The reason it is called the Campden
tablet and not the Long Ashton tablet is because in those days (1920's)
the Chipping Campden Research Station was an outstation of Long Ashton
and principally set up to deal with fruit preservation issues in the
middle of a soft fruit growing area. It did not become independent until
many years later. Now Campden survives and has also absorbed the UK's
baking and brewing research stations (see http://www.campden.co.uk/)
while Long Ashton has long since gone.
Sorry for the historical diversion - may be of interest to some!
Raymond Blockley
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Ray B
skidbro...@tiscali.co.uk
----Original Message----
From: raymond_...@sky.com
Date: 02/11/2011 19:01
To: <cider-w...@googlegroups.com>
Subj: Re: [Cider Workshop] Re: Sodium metabisulphite stock solution
On 01/11/2011 21:35, CarlLeClair wrote:
I never check my SO2 (free or total). I know what I add and why I add it
and that's good enough for me. If I were in business I might, just for
reassurance and for 'due diligence' paperwork, but otherwise I go by
'rule of thumb'. Hope that doesn't shock you! But if you do need checks
of free or total SO2 on a craft basis, then a simple Ripper titration
should suffice.
It doesn't shock me in the least, with all your education and
experience,
Yet Professor Barker may have been shocked to hear of this ;)
Oddly enough, not so! Of course I never knew Bertie Barker since he had retired and died long before I got to Long Ashton. But he did not himself see much value in SO2 for cider making, except perhaps on storage. AFAIR he had tried it experimentally but only obtained erratic and unpredictable results, hence his viewpoint. The problem was that in his day the pH dependency of SO2 a_ction was not understood, and the balance between the inactive ionic and the active molecular form was totally unknown. It was not until Beech and Burroughs took another look at SO2 in the 60's that the story became clearer and really wasn't fully explained and rationalised until the 1970's. I joined Long Ashton at that time, in my young and impressionable years, which is why I am such an advocate for SO2 now!
On the other hand, to give him his due, it was Barker who pretty much invented the Campden tablet (though he started with the Campden solution). It was introduced for the cold sterile bottling of fruit, not for wine or cider making. The idea was that high dose SO2 (ca 1000 ppm) was used as a preservative so that heat was not required. Of course you didn't eat the fruit with all that sulphite in it! You had to cook it to drive off the SO2. It never really caught on for home preservation (people preferred to heat sterilise and vacuum seal in bottling jars) but for a while it was used in the jam industry to store gluts of fruit.
The Campden solution was replaced for home use by the Campden tablet which now lives on in another life. The reason it is called the Campden tablet and not the Long Ashton tablet is because in those days (1920's) the Chipping Campden Research Station was an outstation of Long Ashton and principally set up to deal with fruit preservation issues in the middle of a soft fruit growing area. It did not become independent until many years later. Now Campden survives and has also absorbed the UK's baking and brewing research stations (see http://www.campden.co.uk/) while Long Ashton has long since gone.
Sorry for the historical diversion - may be of interest to some!
Andrew
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Cider Workshop Website
www.ciderworkshop.com
Andrew's Website
www.cider.org.uk
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CarlLeClair
> Oddly enough, not so! Of course I never knew Bertie Barker since he had
> retired and died long before I got to Long Ashton. But he did not
> himself see much value in SO2 for cider making, except perhaps on
> storage. AFAIR he had tried it experimentally but only obtained erratic
> and unpredictable results, hence his viewpoint. The problem was that in
> his day the pH dependency of SO2 action was not understood, and the
> balance between the inactive ionic and the active molecular form was
> totally unknown. It was not until Beech and Burroughs took another look
> at SO2 in the 60's that the story became clearer and really wasn't fully
> explained and rationalised until the 1970's. I joined Long Ashton at
> that time, in my young and impressionable years, which is why I am such
> an advocate for SO2 now!
This is a great historical timeline you bring to our attention.
I know you realize I was having a bit of fun with you as to the
reference to
Professor Barker. What I have appreciated more than your unselfish
time spent
helping us all understand the cider making process better is your
website and it's
wealth of information that is made available to us!
I have found your book reference material as one of the best parts for
me personally.
Having just about finished " Report on the results of investigations
into cidermaking,
carried out on behalf of the Bath and West and Southern Counties
Society in the years
1893 - 1902 " which has reinforced the timeline of the research into
using products such
as SO2 to stabilize the storage of Cider with residual sweetness ?
( pg. 88 ). I was intrigued
with the success of the Devon trials with mustard, however sadly the
flavor profiles had turned
out so poorly. I suppose not to be unexpected ?
Folks, if you want a good read for the wintertime blues, you will not
be disappointed with this book purchase!
A wealth of information and historical perspective to be had here.
Best Regards,
Carl