SC-100A manual
10
Version 3.1c
Appendix B - Sulfite Adjustments
Using the Winemaker Magazine Sulfite Calculator:
Winemaker Magazine's Sulfite Calculator at
https://winemakermag.com/1301-sulfite-calculator
is an excellent tool for calculating how much sulfite should be added to your wine. We will briefly go
over the process here for some clarification.
1.
Select a 'Preferred method of Sulfite addition:'; we recommend using a 10% solution of
Potassium metabisulfite (KMBS). [You can prepare this solution by weighing out 10g of KMBS and
dissolving it in a FINAL volume of 100 mL DI water.]
2.
Next choose the wine type (red or white).
3.
Enter the "volume of wine to be corrected". Choose liters or gallons; we prefer "liters" because
the answer is returned in mL.
4.
Enter the wine’s pH. If you know the % Alcohol by volume and temperature, enter these also
(but you don’t have to).
5.
Now input the "Current level of Free SO
2
" which you determined from measuring Free SO
2
with the Vinmetrica SC-300.
6.
Now look below to the ‘Notes:’ section. You should now see the message "1. The
recommended level of free SO
2
for this type of wine, molecular SO
2
& pH is: [your value] mg/L. Redo
the calculation using this value for desired free SO2 level, if required.” Enter this value in the “Desired
level of free SO2” box.
Press ‘Calculate’ to get the correct “Amount of sulfite to be added:”. The value will be in mL or fluid
ounces of 10% sulfite solution, or in grams if you use sulfite powder as your sulfite additive.
We recommend double checking your calculations. Also, be sure you are using fresh KMBS!
Once you have added the recommended amount of sulfite, stir your wine thoroughly and take another
SO
2
measurement after waiting at least 30 minutes. If the measurement matches the 'Desired level of
free SO
2
' then you are done, otherwise make incremental additions and repeated SO
2
measurements
until you reach your desired level.
Appendix C - Troubleshooting: SO
2
Issues
How stable are the reagents?
The SO
2
reagents and the pH/TA reagents are all warranted to last for 6 months and have a
“use-by” date on the label that is 2 years from date of manufacture. Make sure they are stored tightly
capped, out of the heat and direct sunlight. And of course, these reagents will last much longer if not
cross-contaminated with each other! If the solutions become cloudy or show signs of microbial
growth, they should be replaced.
