noun
white sugar
Refers specifically to refined white sugar, as opposed to brown sugar or other sweeteners.
このレシピでは白砂糖を使います。
This recipe uses white sugar.
黒砂糖 is brown sugar, often less refined and with a stronger molasses flavor.
Compound of 白 (しろ, 'white') and 砂糖 (さとう, 'sugar'). The reading しろざとう reflects rendaku voicing of the second element.