Should I add Campden tablets each time I rack my wine and how do
I measure the level of sulfite in my wine?



Dear Wine Wizard,
The last batch of wine I made was blackberry and it
tasted just right until I added Campden tablets at the rate of 1
tablet per gallon of wine before bottling to stabilize it. It seems that the
Campden tablets change the taste and aroma of the wine and not for the
better. This has happened several times with other batches of wine. I was
also told that I should add Campden tablets at the same rate each time I
rack the wine. Should I add the tablets each time I rack the wine? And is it
necessary to add it before bottling? Is there a proper level of
metabisulfite that I should be adding and, if so, how do you measure the
level of it in your wine?
Joe Giorgianni
Gibbstown, New Jersey


Wine Wizard replies: Hold on there, tiger! If you've got a
standard 0.44 gram Campden tablet and you're putting it in one gallon of
wine, you're blasting it with 66 mg/L sulfur dioxide, which is quite a lot
if you've already been adding a tablet each time you rack. It's no wonder
your wine tasted a little off.

You don't want to put too much SO2 in your wine. The American
and French governments limit the amount that commercial wineries can add to
350 mg/L of total S02. At this level it's almost certain you'd be able to
pick up free SO2 in the nose and higher levels the wine can become downright
unpleasant to imbibe. Also keep in mind the difference between free and
total SO2. Free SO2, the portion that is not bound with aldehydes, sugars or
other oxidizable substances in the wine, is the form that is available for
anti-oxidant protection and anti-microbial activity. Free SO2 will disappear
over time into a wine, binding with the above-mentioned substrates, causing
the ability of a wine to retard oxygen and microbes to decline as well.

This is the primary reason most recipes recommend you add
sulfites every time you rack because - by the time most of us get around to
racking a wine (say, it's every month) - it's time to add some more sulfur
dioxide anyway. Do you always have to do it? That answer is up to you and
your wine. If the wine is throwing a ton of sediment all the time and you
find yourself having to rack it every two weeks, you don't necessarily have
to add it every time. If your wine is startlingly clear and you haven't
racked in two months, your free SO2 levels might be getting dangerously low
and you might want to bump your free mg/L into the 25 range again. Never add
S02 without testing the wine first. There does seem to be a point in a
wine's life when the free S02 levels off and you don't need to add it as
frequently. Once a wine is off its lees and approaching bottling, be really
careful about adding S02.

So how do you measure the level in your wine? Sulfite measuring
kits are available ($10 U.S. for a packet of ten) under the brand name
CHEMetrics Titrets. These are good at-home sulfur-assaying kits that you can
use to measure the amount of sulfites in your wine. If you really want to
get serious, go through a wine lab supply house like The Wine Lab
(707-224-7903 www.thewinelab.com) or Vinquiry (805-922-6321,
www.vinquiry.com) to get a bench-top set up. This costs XX. It will, if you
do a lot of sulfur analysis and plan to make wine for many years to come, be
worth it in the long run.


With regards to pre-bottling sulfur adds: Free SO2 should always
be adjusted before bottling. For white wines typical levels are 30 to 35
mg/L and for reds 25 to 30 mg/L. Most winemakers try to err on the low side
as too much SO2 will be detectable in the nose. You can safely lean to the
low side if the wine is clean, bright, dry and especially if it has been
sterile-filtered before bottling.

Now you're going to ask how to add it and how to calculate it
out for whatever volume of wine you've got. Most home winemakers have access
to sulfur dioxide through potassium metabisulfite, available in either
powdered or solid tablet forms. As you mentioned, the solid tablets are
called Campden tablets and many home winemakers see them as a mysterious
"magic pill" that they know does something for their wine but they're not
quite sure what. For those of you who just want the facts:

Potassium metabisulfite is 57% sulfur dioxide.
Most Campden tablets weigh 0.44 g
To figure out how many grams of potassium metabisulfite powder
to add to your volume to give you the desired concentration (in mg/L or ppm)
of total sulfur dioxide, use the following equation:
(gallons of wine you have) (3.785) (ppm or mg/L of total SO2 you
want to add)/(1000) (0.57)

Say I've got 5 gallons of wine that I'm getting ready for
bottling. I measured my free SO2 and have found it to be sitting at 10 free.
I want to get it into the 30 mg/L free SO2 range. Since my wine is dry, the
sulfur dioxide won't get bound up as quickly so I'll take a stab at adding
25

(30-10 + 5 for guess work) mg/L total. (5 ) (3.785)( 25) /
(1000)(0.57)= 0.83 grams

You'll have to add 0.83 grams (or 830 mgs) of potassium
metabisulfite powder to your 5 gallons of wine to get a free SO2 level of
about 30 mg/L. Now, if you only have Campden tablets or don't have a scale,
keep these numbers in mind: Standard Campden tablets are 0.44g of potassium
metabisulfite (though they do come in other sizes- read packages carefully!)
1 teaspoon = about 5 grams of potassium metabisulfite (though be
careful measuring with teaspoons can give you a 20% error or more!) If you
can afford the scale, measuring in grams is the way to go.

1 gram = 1000 mg
0.2642 gallons = 1 liter or 1 gallon = 3.785 liters.

Another alternative is to usethe 10% solution method described
in "Solving the Sulfite Puzzle" (Winter 2001). Just be aware that a 10
percent potassium metabisulfite solution only yields 5.7 percent sulfur
dioxide??

The guess work lies in estimating how much of your sulfur
dioxide will get bound up and will not be "free SO2". Sugar, lees and
aldehyde will always aid in the binding process and you'll lose your free
SO2 very quickly. Keeping this and the total amount of SO2 you've added over
a wine's lifetime in mind.


Do keep in mind the long-term plan for the wine. Don't let total
amounts of SO2 you're adding get out of control. Adding too much will
eventually spoil your wine. In the end, it's best to let a free SO2 analysis
and your nose be your guides - not a racking schedule. For more information
refer to "Solving the Sulfite Puzzle (Winter 2001).

Użytkownik "MikroBajt" <m...@o...pl> napisał w wiadomości
news:nr5mp9g0gqqh.12dy84tgwqzp3$.dlg@40tude.net...
> kupiłem ostatnio buteleczkę
> zachodzę do domu, wczytuję się
> a tu na samym dole dopisek: "Zawiera siarczyny" :(
>
> Ktoś fachowo mógłby się wypowiedzieć nt.
> Może każde wino zawiera te "cuda"
> a tylko nie piszą
> (W kazdym razie skojarzyło mi się to w winem marki "Wino" ;)
>
> Czy jest jakaś gwarancja, że jak nie ma tego dopisku
> to dany napój nie zawiera ich?
> Jak to sprawdzić, jak kupować??
>
> PS.
> Smakuje nie najgorzej ;)