Sulphite Calculator Manual - Fermsoft - Winemaking and Brewing Software

Home | Products | Help |

Choose the sulphite source by selecting potassium metabisulphite, sodium metabisulphite, or sodium bisulphite from the drop-down list. Most winemakers use potassium metabisulphite for additions to wine, but other sulphite forms are often used in sanitizing solutions. If you are using campden tablets, check the ingredients, then select the sulphite source from the drop-down list.
Sulphite is available either in powder or tablet form. In addition, many winemakers prepare a sulphite solution by dissolving powder in water (see the resources section for information regarding the preparation of sulphite solutions). Click on the sulphite form that you are using. If you are using a solution, you also need to specify the strength of the solution as a percentage (1 to 100). A 10% solution is very common to use. If you are using tablets, you need to specify the tablet weight in grams. This weight should be printed on the package.

Set your batch size and specify the measurement units. You can choose either, U.S. gallons, imperial gallons, or litres as measurement units.
Set the pH or your wine. Setting the pH is only required if you have chosen "Molecular SO2" as the target. If the target is set to "Total Free SO2", the program will ignore the pH data.

You can select either total free SO2 or molecular SO2 as the target. If total free SO2 is selected, the program will calculate how much sulphite is required in order to reach a specified total free SO2 level. If molecular SO2 is selected as the target, the program will calculate how much sulphite is required in order to reach a specified molecular SO2 level. If molecular SO2 is chosen as the target, the wine pH must also be entered in the batch data section.
Molecular SO2 is the active SO2 component that protects your wine from spoilage. You should choose this target to be sure that your wine is protected. See the resources page for recommended molecular SO2 levels.

Enter the existing total free SO2 level of your wine. This is a measured amount that is found by titration. Titrets are commonly used by home winemakers for this purpose.
Enter the desired target SO2 level. If free SO2 is selected as the target, the first field will be used. If molecular SO2 is selected as the target, the second field will receive the input data.
Numbers can be entered using 2 methods. Numbers can be typed directly into the text fields. This method has a greater level of precision because the text fields will accept decimal numbers as input. Numbers can also be entered by using the up/down arrows beside each text entry field. These arrows will increment/decrement the numbers.

Once all the settings have been specified, the sulphite required to reach the designated target level is calculated by pressing the Calculate button. The program will then validate the input data. The program will display a message if any of the data is unacceptable. If all data is within acceptable parameters, the required addition fields will display the amount of sulphite required to reach the target level.
If powder is chosen as the sulphite form, the amount of powder required can be specified in g, oz (av.), tsp, or tbsp by choosing the desired units from the dropdown list. If a solution is specified, the amount can specified in ml, oz (fl), tsp, or tbsp. If tablets is chosen, the amount shown is the number of tablets.

Most winemakers will use many of the same settings every time the program is used. If your desired settings differ from the program defaults, personal defaults can be set by clicking the Settings button. After selecting the desired defaults, click OK. The personal settings have been saved and will appear next time the program is run.
The program defaults can be restored by clicking the Restore Program Defaults button in the settings window.

Help information is maintained on the program web site rather than in the software itself. This ensures that the information can be updated as needed, without releasing an upgrade to the software. General information regarding the use of sulphite in winemaking can be found on the resources page.
The feedback page can be used to contact the author if further help or information is required.

The author is always interested in hearing about bugs and ideas for possible enhancements to the software. The current version has no known bugs, but if any bugs are discovered, report them through the feedback page. Bug fixes will be released as soon as possible after discovery.