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