A 25 kg bag of brewing sugar.
This item is also called Dextrose monohydrate, and glucose - there is no difference.
Brewing sugar is used rather than table sugar (sucrose) for taste.
The Science bit: Yeast cannot ferment sucrose and must first break it down into a molecule of Fructose and Glucose. To do this it makes an ezyme called invertase. Invertase has a bitter taste that can be noticable in high alcohol yeast brews created with table sugar.