I have had some good advice from this wine group but still remain
confused about when to use sulphite.I have successfully made some
excellent red and white wine from grapes grown in southern England.I
seem to get some very good juice (Brix 19)with a good acid balance.My
good wines were my first attempts a couple of years ago,but I recall
that they were drunk within about 12 months after harvest.My recent
problems have been with longer storage wine which unfortunately has
been without any sulphite.The whites have become somewhat flat and
with a touch of sherry like flavour,and the reds have lost their
fruitiness and also become a little metallic.I am sure that this is
all due to oxidation,and I certainly plan to use a minimal amount of
sulphite for this years winemaking.I thought that I would be making
organic wine,but I have discovered that organic winemakers do use
sulphites or the complete purists do every operation under a CO2
blanket.I certainly do not wish to go down the CO2 route,so I am
resigned to using a minimum amount of sulphites,but I am unclear when
to use the sulphites.

I usually wash and sort my grapes and have been letting them ferment
on the natural yeasts.All of the grapes I have processed so far have
fermented the natural(+added) sugar out completely in a few weeks.As I
understand it,the early addition of sulphite (e.g.50ppm)is used to
kill off any remaining bacteria and suppress the 'bad' yeasts.My
question is whether this sulphite also absorbs oxygen at this early
fermentation stage,and therefore keep the juice fresh?I thought that
the CO2 given off during the fermentation protects the wine from
oxidation,but maybe the oxygen remains to do damage later on.So is
this early sulphite addition important?

The next question is whether to add sulphite at the first racking
stage,say after a couple of months,when the wine is fairly fully
fermented(another 50ppm?).I understand that most of the initial
sulphite (if added) will be used up during the fermentation process,so
maybe this is the most important addition.I probably do not expect an
MLR fermentation as most of my juices are reasonably but not too
acidic.Will this sulphite addition protect the wine (usually stored in
glass demijohns)if I keep it for a couple of years?

So,in summary,I am clearly suffering oxidation problems and plan to
add sulphite either

(i)both immediately after pressing(and then hope the natural yeast
gets going after a delay) and then after first racking or
(ii)just after first racking

I would very much like some advice.

Best regards
Michael

On Jan 25, 5:43*am, michael wrote:
I have had some good advice from this wine group but still remain
confused about when to use sulphite.I have successfully made some
excellent red and white wine from grapes grown in southern England.I
seem to get some very good juice (Brix 19)with a good acid balance.My
good wines were my first attempts a couple of years ago,but I recall
that they were drunk within about 12 months after harvest.My recent
problems have been with longer storage wine which unfortunately has
been without any sulphite.The whites have become somewhat flat and
with a touch of sherry like flavour,and the reds have lost their
fruitiness and also become a little metallic.I am sure that this is
all due to oxidation,and I certainly plan to use a minimal amount of
sulphite for this years winemaking.I thought that I would be making
organic wine,but I have discovered that organic winemakers do use
sulphites or the complete purists do every operation under a CO2
blanket.I certainly do not wish to go down the CO2 route,so I am
resigned to using a minimum amount of sulphites,but I am unclear when
to use the sulphites.

I usually wash and sort my grapes and have been letting them ferment
on the natural yeasts.All of the grapes I have processed so far have
fermented the natural(+added) sugar out completely in a few weeks.As I
understand it,the early addition of sulphite (e.g.50ppm)is used to
kill off any remaining bacteria and suppress the 'bad' yeasts.My
question is whether this sulphite also absorbs oxygen at this early
fermentation stage,and therefore keep the juice fresh?I thought that
the CO2 given off during the fermentation protects the wine from
oxidation,but maybe the oxygen remains to do damage later on.So is
this early sulphite addition important?

The next question is whether to add sulphite at the first racking
stage,say after a couple of months,when the wine is fairly fully
fermented(another 50ppm?).I understand that most of the initial
sulphite (if added) will be used up during the fermentation process,so
maybe this is the most important addition.I probably do not expect an
MLR fermentation as most of my juices are reasonably but not too
acidic.Will this sulphite addition protect the wine (usually stored in
glass demijohns)if I keep it for a couple of years?

So,in summary,I am clearly suffering oxidation problems and plan to
add sulphite either

(i)both immediately after pressing(and then hope the natural yeast
gets going after a delay) and then after first racking *or
(ii)just after first racking

I would very much like some advice.

Best regards
Michael

Q1: How clean is your equipment, including demijohns before you add
the wine?
Q2: Are you bottling at some point? - how are you drinking it and are
you leaving too much head space in the demi?

I used to add sulfite at crush, press and each time I racked per some
previous advice. SInce then I have backed way down. This year I only
sulfited at crush and I have been checking my so2 levels and they are
still about 50ppm so I have not added more - even through bottling. I
dont think it is lack of sulfite that is giving you what your getting.
Maybe some of the more experienced folks on this board can help, but I
certainly see more problems with ullage than sulfite.

michael wrote:

I have had some good advice from this wine group
but still remain confused about when to use
sulphite.I have successfully made some excellent
red and white wine from grapes grown in southern
England.I seem to get some very good juice (Brix
19)with a good acid balance.My good wines were
my first attempts a couple of years ago,but I
recall that they were drunk within about 12
months after harvest.My recent problems have
been with longer storage wine which
unfortunately has been without any sulphite.The
whites have become somewhat flat and with a
touch of sherry like flavour,and the reds have
lost their fruitiness and also become a little
metallic.I am sure that this is all due to
oxidation,and I certainly plan to use a minimal
amount of sulphite for this years winemaking.I
thought that I would be making organic wine,but
I have discovered that organic winemakers do use
sulphites or the complete purists do every
operation under a CO2 blanket.I certainly do not
wish to go down the CO2 route,so I am resigned
to using a minimum amount of sulphites,but I am
unclear when to use the sulphites.

I usually wash and sort my grapes and have been
letting them ferment on the natural yeasts.All
of the grapes I have processed so far have
fermented the natural(+added) sugar out
completely in a few weeks.As I understand it,the
early addition of sulphite (e.g.50ppm)is used to
kill off any remaining bacteria and suppress the
'bad' yeasts.My question is whether this
sulphite also absorbs oxygen at this early
fermentation stage,and therefore keep the juice
fresh?I thought that the CO2 given off during
the fermentation protects the wine from
oxidation,but maybe the oxygen remains to do
damage later on.So is this early sulphite
addition important?

The next question is whether to add sulphite at
the first racking stage,say after a couple of
months,when the wine is fairly fully
fermented(another 50ppm?).I understand that most
of the initial sulphite (if added) will be used
up during the fermentation process,so maybe this
is the most important addition.I probably do not
expect an MLR fermentation as most of my juices
are reasonably but not too acidic.Will this
sulphite addition protect the wine (usually
stored in glass demijohns)if I keep it for a
couple of years?

So,in summary,I am clearly suffering oxidation
problems and plan to add sulphite either

You may also be experiencing some reduction
problems. Oxidation and reduction go hand in
hand. I am not a chemist but my understand is
that it is more complex than just "oxidation".
Some of the off flavors (metallic as an example)
may be the result of reduction reactions taking
place simultaneously with the oxidation
reactions.


(i)both immediately after pressing(and then hope
the natural yeast
gets going after a delay) and then after first
racking or (ii)just after first racking

I would very much like some advice.

Best regards
Michael

There is some excellent information he

http://brsquared.org/wine/Articles/SO2/SO2.htm

Although it can look somewhat intimidating at
first glance, I think you can get the main points
without getting too involved in the science.
Just be patient and read through and then go back
and get some general information or rules of
thumb to help you out. Or, if you want to
research the issue in detail, this is a good
place to start.

I would recommend that you consider building / buying the kit for
testing SO2 levels in your wines and make your sulfite additions based
on need and pH - not on recipe. While I'm not convinced that sulfite
levels are causal to your oxidation problems, keeping your wines at the
appropriate levels of SO2 is your best insurance against various
microbial spoilage problems.

AxisOfBeagles wrote:

I would recommend that you consider building /
buying the kit for testing SO2 levels in your
wines and make your sulfite additions based on
need and pH - not on recipe. While I'm not
convinced that sulfite levels are causal to your
oxidation problems, keeping your wines at the
appropriate levels of SO2 is your best insurance
against various microbial spoilage problems.

I agree that pH is a MAJOR factor along with SO2.

Generally, from my experience, red wines can be
handled fairly roughly - splashing at racking
(which can be beneficial) etc. as long as the pH
is kept around 3.5 and the pH levels maintained
for that pH.

On Jan 25, 2:43*am, michael wrote:
I have had some good advice from this wine group but still remain
confused about when to use sulphite.I have successfully made some
excellent red and white wine from grapes grown in southern England.I
seem to get some very good juice (Brix 19)with a good acid balance.My
good wines were my first attempts a couple of years ago,but I recall
that they were drunk within about 12 months after harvest.My recent
problems have been with longer storage wine which unfortunately has
been without any sulphite.The whites have become somewhat flat and
with a touch of sherry like flavour,and the reds have lost their
fruitiness and also become a little metallic.I am sure that this is
all due to oxidation,and I certainly plan to use a minimal amount of
sulphite for this years winemaking.I thought that I would be making
organic wine,but I have discovered that organic winemakers do use
sulphites or the complete purists do every operation under a CO2
blanket.I certainly do not wish to go down the CO2 route,so I am
resigned to using a minimum amount of sulphites,but I am unclear when
to use the sulphites.

I usually wash and sort my grapes and have been letting them ferment
on the natural yeasts.All of the grapes I have processed so far have
fermented the natural(+added) sugar out completely in a few weeks.As I
understand it,the early addition of sulphite (e.g.50ppm)is used to
kill off any remaining bacteria and suppress the 'bad' yeasts.My
question is whether this sulphite also absorbs oxygen at this early
fermentation stage,and therefore keep the juice fresh?I thought that
the CO2 given off during the fermentation protects the wine from
oxidation,but maybe the oxygen remains to do damage later on.So is
this early sulphite addition important?

The next question is whether to add sulphite at the first racking
stage,say after a couple of months,when the wine is fairly fully
fermented(another 50ppm?).I understand that most of the initial
sulphite (if added) will be used up during the fermentation process,so
maybe this is the most important addition.I probably do not expect an
MLR fermentation as most of my juices are reasonably but not too
acidic.Will this sulphite addition protect the wine (usually stored in
glass demijohns)if I keep it for a couple of years?

So,in summary,I am clearly suffering oxidation problems and plan to
add sulphite either

(i)both immediately after pressing(and then hope the natural yeast
gets going after a delay) and then after first racking *or
(ii)just after first racking

I would very much like some advice.

Best regards
Michael

It does sound like oxidation, especially the whites. Colour is a good
indicator, basically both white and reds move towards brown, depending
on the degree of oxidation.

Based on your described procedure, don't use sulfite when you crush.
Oxygen is usually not an issue at this stage, if fact the yeasts need
oxygen to ferment properly. If you don't do ML, sulfite at the first
racking/pressing. Keep your equipment as clean as possible and
sanitize everything that comes in contact with the wine. If you can,
measure the sulfite levels before each racking and add some more if
needed. Rack carefully avoiding splashing and minimize the number of
rackings and get it it the bottle as soon as the wine clears.

In this regime you do have to be careful as Paul mentioned to avoid
reduction problems, so you need to smell and taste the wine regularly,
which will introduce some oxygen, so there is always a tradeoff. But
if minimizing sulfites is your main goal and you don't want to drink
the wine within months, some increased risks are unavoidable.

Pp

There are two schools of thought on early addition of sulfite to white
wines. One camp feels it is best not to sulfite must as the browning
actually falls out as the wine clears leaving you with a wine lighter
in color and resistant to browning since the reactions already
occurred. The other camp uses 50 to 100 PPM at crush based on health
of the grapes, moldy grapes get the higher dose. I sulfite but have
tried the no sulfite avenue too.

Washing grapes - especially if you are depending on natural yeast, is
not recommended. Cultivated yeast is cheap, predictable and reliable,
using natural yeast could result in a batch not finishing to dryness
but it seems to be fine with your wines.

Measuring sulfite levels for red wines requires both a decent
calibrated pH meter and an aeration oxidation apparatus; that will run
approximately $300 so if you are not looking to jump into that water
it's understandable. Titrettes from Chemetrics work fine on whites
and are relatively cheap.

Your first rack should be with some splashing; after that racks should
gentle with no splashing. If you follow that process you can probably
just add 1/8 level teaspoon of potassium metabisulfite per 5 gallon
(US) to the wine each rack and will be safe; that is around 20 PPM.
As mentioned by others, sulfite additions are governed by pH, higher
pH requires more sulfite so a good pH meter is worth having. Since
you mentioned your acids are not high you might need 1/4 teaspoon, at
least at bottling. That is where the pH measurement would be helpful,
a local school's sciences department would have one if you don't want
to do that.

Joe

Comment on the cost of an AO apparatus ... I agree that this is one of
the more costly items a home winemaker might invest in, but I would
argue that it is also one of the more critical tools in a home winery
.... knowing the SO2 levels helps the home winemaker manage their wines,
and winemaking decisions, such that they can avoid some costly mistakes.

I was able to 'build' a kit for somewhat less than your estimate.
Titration stand, beakers, tubes, etc can all be purchased separately
from any of the better online science supply houses. And rather than
pay for the more expensive vacuum pump, the system can be 'reversed'
and a cheaper aquarium air pump used - as long as all the fittings are
tight it works just fine (and can be demonstrated to do so by
comparative tests with vacuum aspiration kits). Still costs a couple
hundred bucks tho, so your point is well taken.

For my $, investing in an AO appartus ranks along with a top-quality pH
meter, a good TA titration kit, and a paper chromatography set up as
'essentials' in my winery lab.

Now if I could only figure out how to build an accurate ebulliometer on
the cheap!




On 2008-01-25 10:27:01 -0800, Joe Sallustio said:


Measuring sulfite levels for red wines requires both a decent
calibrated pH meter and an aeration oxidation apparatus; that will run
approximately $300 so if you are not looking to jump into that water
it's understandable. Titrettes from Chemetrics work fine on whites
and are relatively cheap.

On 25 Jan, 18:27, Joe Sallustio wrote:
There are two schools of thought on early addition of sulfite to white
wines. *One camp feels it is best not to sulfite must as the browning
actually falls out as the wine clears leaving you with a wine lighter
in color and resistant to browning since the reactions already
occurred. *The other camp uses 50 to 100 PPM at crush based on health
of the grapes, moldy grapes get the higher dose. *I sulfite but have
tried the no sulfite avenue too.

Washing grapes - especially if you are depending on natural yeast, is
not recommended. *Cultivated yeast is cheap, predictable and reliable,
using natural yeast could result in a batch not finishing to dryness
but it seems to be fine with your wines.

Measuring sulfite levels for red wines requires both a decent
calibrated pH meter and an aeration oxidation apparatus; that will run
approximately $300 so if you are not looking to jump into that water
it's understandable. *Titrettes from Chemetrics work fine on whites
and are relatively cheap.

Your first rack should be with some splashing; after that racks should
gentle with no splashing. *If you follow that process you can probably
just add 1/8 level teaspoon of potassium metabisulfite per 5 gallon
(US) to the wine each rack and will be safe; that is around 20 PPM.
As mentioned by others, sulfite additions are governed by pH, higher
pH requires more sulfite so a good pH meter is worth having. *Since
you mentioned your acids are not high you might need 1/4 teaspoon, at
least at bottling. *That is where the pH measurement would be helpful,
a local school's sciences department *would have one if you don't want
to do that.

Joe

Thanks for all of the advice,which is most helpful.In reply to the
questions about cleanliness,keeping vessels full,etc,I do not think
that can be a problem.I always clean out all of my containers with
dilute bleach(carefully rinsed out afterwards) each time they are
used.In addition I always top up my vessels,just allowing enough for
expansion.I use 1 gallon glass carboys for the fermentation,and always
top up after racking.After the second racking and when the wine is
reasonably stable(usually about 6 months after harvest)I replace the
airlock with a rubber bung-occasionally the bung comes out after a
warm period,but usually replaced within a day or so.I do sample a
small amount of the wine from time to time and hope that this does not
introduce too much air.I do not bottle my wines at all,but transfer
each 1 gallon batch into full 1 litre carafes(with rubber stopper)-
sorry about the mixed units-and then drink it.The only time I bottle
the wine is if I am giving some wine to friends and family.

I have found that washing the grapes does help to reduce the off
flavours in the early part of the fermentation,and surprisingly does
not stop the natural yeast starting the fermentation and finishing to
dryness.Occasionally,I have a batch of grapes that have some botrytis
and I sulphite them and add a commercial yeast,but this is not my
usual procedure.

I was surprised at the comment that measured sulphite levels were
still high (50ppm) at the end of a particular fermentation.I thought
that the initial sulphite added at crush was essentially taken up
during the fermentation.I thought that the initial sulphite was to
kill moulds and bacteria,and prevent oxidation to some extent in the
early stages.This does not seem to be a problem with me and so I was
hoping to miss out this stage such as to obtain natural yeast
fermentation.

I think,but not sure,that my problem is oxidation during secondary
storage without sulphite,or a temperature fluctuation and light
problem in my garage.Most of the year the temperature in the brick
garage where I make my wine is around 50F-60F,at least for the period
October-April,when most of the changes take place.However clearly the
garage warms up as the summer progresses and there are periods when
the temperature is 75F-80F for a period in June-September.I am
thinking to rig up a curtain arrangement to reduce light and
temperature levels a little,but not sure this is important.

I like the idea of visiting local school chemistry laboratories and
have a look at the pH equipment they have.I tend to use litmus papers
but these are not very accurate.I also certainly do not feel like
laying out too much cash to determine free and bound sulphite levels-
this is mentioned in some of my books on winemaking,but I would rather
add a small amount of sulphite depending on pH.

Keep the advice coming.I appreciate it

Best regards
Michael

"Paul E. Lehmann" wrote in message
. ..
michael wrote:

snip

(i)both immediately after pressing(and then hope
the natural yeast
gets going after a delay) and then after first
racking.

YUP.........

I would very much like some advice.

Best regards
Michael

There is some excellent information he

http://brsquared.org/wine/Articles/SO2/SO2.htm

Although it can look somewhat intimidating at
first glance, I think you can get the main points
without getting too involved in the science.
Just be patient and read through and then go back
and get some general information or rules of
thumb to help you out. Or, if you want to
research the issue in detail, this is a good
place to start.


Michael

That link even intimidates me !! ;o)

Let me see if I can summarize just a little. ;o)

Oxydation - two kinds we are concerned with:
Enzymatic and reductive. Enzymatic is fast while reductive is
slow(er). Enzymatic is what causes fruit to brown quickly.
Cut an apple in half and you can almost see it turn brown.
SO2 inhibits/destroys these enzymes. So the more prone the
fruit is to this kind of browning, the more important it is to use
sulfite at crush. And, by destroying these enzymes, it actually
leaves_more_oxygen in the must for the yeast to use to get
started. At "aseptic" levels, SO2 also kills things like
Bot, Bret, fungus, etc. so you need to use enough sulfite at
crush to take care of these things also.

Reductive is pretty much just chemical reactions which happen
any time oxygen is present. These happen more slowly and temp
plays a large part in how fast these "ageing" reactions take place,
but SO2 slows this conciderably, so maintaining SO2 levels up
to and into bottling is also important. An "aseptic" level is also
important here to prevent certain kinds of microbial spoilage.

Go to that link and look in chapter 7 for chart number 3 and
figure number 6. These pretty much tell you the relationships
that you need to know to determine dosage required. If you
understand that an "aseptic" level is slightly higher than 0.8ppm
molecular, you should have no problem using these.

Memory ain't what it used to be. Hope others jump in and
add to this. HTH

Frederick

On Jan 26, 6:39 am, michael wrote:
On 25 Jan, 18:27, Joe Sallustio wrote:



There are two schools of thought on early addition of sulfite to white
wines. One camp feels it is best not to sulfite must as the browning
actually falls out as the wine clears leaving you with a wine lighter
in color and resistant to browning since the reactions already
occurred. The other camp uses 50 to 100 PPM at crush based on health
of the grapes, moldy grapes get the higher dose. I sulfite but have
tried the no sulfite avenue too.

Washing grapes - especially if you are depending on natural yeast, is
not recommended. Cultivated yeast is cheap, predictable and reliable,
using natural yeast could result in a batch not finishing to dryness
but it seems to be fine with your wines.

Measuring sulfite levels for red wines requires both a decent
calibrated pH meter and an aeration oxidation apparatus; that will run
approximately $300 so if you are not looking to jump into that water
it's understandable. Titrettes from Chemetrics work fine on whites
and are relatively cheap.

Your first rack should be with some splashing; after that racks should
gentle with no splashing. If you follow that process you can probably
just add 1/8 level teaspoon of potassium metabisulfite per 5 gallon
(US) to the wine each rack and will be safe; that is around 20 PPM.
As mentioned by others, sulfite additions are governed by pH, higher
pH requires more sulfite so a good pH meter is worth having. Since
you mentioned your acids are not high you might need 1/4 teaspoon, at
least at bottling. That is where the pH measurement would be helpful,
a local school's sciences department would have one if you don't want
to do that.

Joe

Thanks for all of the advice,which is most helpful.In reply to the
questions about cleanliness,keeping vessels full,etc,I do not think
that can be a problem.I always clean out all of my containers with
dilute bleach(carefully rinsed out afterwards) each time they are
used.In addition I always top up my vessels,just allowing enough for
expansion.I use 1 gallon glass carboys for the fermentation,and always
top up after racking.After the second racking and when the wine is
reasonably stable(usually about 6 months after harvest)I replace the
airlock with a rubber bung-occasionally the bung comes out after a
warm period,but usually replaced within a day or so.I do sample a
small amount of the wine from time to time and hope that this does not
introduce too much air.I do not bottle my wines at all,but transfer
each 1 gallon batch into full 1 litre carafes(with rubber stopper)-
sorry about the mixed units-and then drink it.The only time I bottle
the wine is if I am giving some wine to friends and family.

I have found that washing the grapes does help to reduce the off
flavours in the early part of the fermentation,and surprisingly does
not stop the natural yeast starting the fermentation and finishing to
dryness.Occasionally,I have a batch of grapes that have some botrytis
and I sulphite them and add a commercial yeast,but this is not my
usual procedure.

I was surprised at the comment that measured sulphite levels were
still high (50ppm) at the end of a particular fermentation.I thought
that the initial sulphite added at crush was essentially taken up
during the fermentation.I thought that the initial sulphite was to
kill moulds and bacteria,and prevent oxidation to some extent in the
early stages.This does not seem to be a problem with me and so I was
hoping to miss out this stage such as to obtain natural yeast
fermentation.

I think,but not sure,that my problem is oxidation during secondary
storage without sulphite,or a temperature fluctuation and light
problem in my garage.Most of the year the temperature in the brick
garage where I make my wine is around 50F-60F,at least for the period
October-April,when most of the changes take place.However clearly the
garage warms up as the summer progresses and there are periods when
the temperature is 75F-80F for a period in June-September.I am
thinking to rig up a curtain arrangement to reduce light and
temperature levels a little,but not sure this is important.

I like the idea of visiting local school chemistry laboratories and
have a look at the pH equipment they have.I tend to use litmus papers
but these are not very accurate.I also certainly do not feel like
laying out too much cash to determine free and bound sulphite levels-
this is mentioned in some of my books on winemaking,but I would rather
add a small amount of sulphite depending on pH.

Keep the advice coming.I appreciate it

Best regards
Michael

I'm not sure how 50 PPM free SO2 can ever remain post fermentation if
normal quantities are used but I guess anything is possible... My
assumption is there is no free sulfite remaining after a healthy
vigorous fermentation.

I think a little sulfite will do you a world of good here. There is
another form you may want to consider given your container size;
Campen Tablets are readily available and might be more convenient.


Joe

The use of suphite for the protection of your wine is all dependant on
the style and future consumption of your wine. If you want a wine to
last longer in bottle you are going to require an addition of sulphite
to protect your wine. When to add sulphite it depends on pH and the
use of indigenous yeasts. THe lower the pH the less likely you will
suffer oxidation issues. The lower the temperature of storage the less
oxidation issues you will have. The less ullage in your filled bottles
the less oxidation you will have. Ullage is the amount of airspace in
your bottle. Use a combination of these when storing your wine and it
will last longer.
Because you are not using a foregien yeast i would not reccomend using
sulphites before fermentation because this will limit your sucess
during fermentation. However it is very important that you use
sulphites immediately after fermentation finishes or just before the
end of ferment if you want to retain some residual sugar. This is the
most important time to protect your wine from oxidation and thus
prevent future oxidation. It is essential you know your sulphur levels
so the sulphur kit is also good advice. At bottling i reccomend at
leat 15-20ppm of free SO2. Maybe a little higher because your probably
not bottling with an inert gas cover. Its ok to oxidise before
fermentation even hyper oxidation has shown to have merits but after
primary fermentation especilly if you not going through Malo you must
use sufficient quantities of Sulphites to protect your wine and
monitor its progression, ie if you rack you will lose some free SO2
thus making your wine more susceptible to oxidation, good luck and
great wine,
SDH
Bachelor of Viticulture and Oenology

On 29 Jan, 06:41, wrote:
The use of suphite for the protection of your wine is all dependant on
the style and future consumption of your wine. If you want a wine to
last longer in bottle you are going to require an addition of sulphite
to protect your wine. When to add sulphite it depends on pH and the
use of indigenous yeasts. THe lower the pH the less likely you will
suffer oxidation issues. The lower the temperature of storage the less
oxidation issues you will have. The less ullage in your filled bottles
the less oxidation you will have. Ullage is the amount of airspace in
your bottle. Use a combination of these when storing your wine and it
will last longer.
Because you are not using a foregien yeast i would not reccomend using
sulphites before fermentation because this will limit your sucess
during fermentation. However it is very important that you use
sulphites immediately after fermentation finishes or just before the
end of ferment if you want to retain some residual sugar. This is the
most important time to protect your wine from oxidation and thus
prevent future oxidation. It is essential you know your sulphur levels
so the sulphur kit is also good advice. At bottling i reccomend at
leat 15-20ppm of free SO2. Maybe a little higher because your probably
not bottling with an inert gas cover. Its ok to oxidise before
fermentation even hyper oxidation has shown to have merits but after
primary fermentation especilly if you not going through Malo you must
use sufficient quantities of Sulphites to protect your wine and
monitor its progression, ie if you rack you will lose some free SO2
thus making your wine more susceptible to oxidation, good luck and
great wine,
SDH
Bachelor of Viticulture and Oenology

Thanks for that very clear piece of advice.I probably will continue to
wash the grapes,ferment on natural yeast and add sulphite after the
fermentation has finished,just as you describe.I tend not to bottle
but rack the wine into 1 gallon demijohns-at this point I intend to
sulphite.One final point.When you say add 15-20ppm of free SO2,is that
very approximately 0.5 Campden tablet/gallon or 0.1g of metabisulphite/
gallon?I am a little confused after reading all the science about
molecular SO2,free SO2,total SO2,bound SO2.
Thanks again
Michael

"michael" wrote in message
...
Thanks for that very clear piece of advice.I probably will continue to
wash the grapes,ferment on natural yeast and add sulphite after the
fermentation has finished,just as you describe.I tend not to bottle
but rack the wine into 1 gallon demijohns-at this point I intend to
sulphite.One final point.When you say add 15-20ppm of free SO2,is that
very approximately 0.5 Campden tablet/gallon or 0.1g of metabisulphite/
gallon?I am a little confused after reading all the science about
molecular SO2,free SO2,total SO2,bound SO2.
Thanks again
Michael

Another alternative. Buy a bottle of Campden tablets and follow
the instructions on the bottle (eg. 1 tablet per gallon). Problem
solved......... )