Place the main ingredient in a stainless steel bowl.
Make sure that the temperature of the main ingredient is 20°C / 68°F. If not, temper it.
Add some 65° Brix simple syrup that has a temperature of 20°C / 68°F. Speaking in very general terms, a good starting point is 1 part simple syrup to 4 parts of the main ingredient.
Whisk the mixture thoroughly. Take a reading on the refractometer. It should read 16° to 19° Brix. The ideal amount is 17° Brix, which is not too sweet but sweet enough. For savory applications, reduce the Brix to 12° to 15° or less, if desired. Always taste to make sure the flavor is to your liking. It is good to trust a refractometer, but trust your taste buds as well.
Pour the granité base into a stainless steel hotel pan. The size will depend on the desired amount.
Place the pan in a –18°C / 0°F freezer.
After 45 minutes to 1 hour, take the pan out of the freezer and scrape the ice crystals that will have formed around the rim of the pan.
Repeat this process every 30 minutes, always scraping in a circular motion to ensure even crystal formation.
Once all the liquid has frozen, transfer to a frozen 10-cm- / 4-in-deep hotel pan and cover. Return to the freezer and reserve for service.