Disclosed herein are compositions comprising polysaccharide particles with an average size of about 0.1-10 mm. These particles comprise at least (i) about 50%-90% by weight water or an aqueous solution, and (ii) about 10%-50% by weight insoluble alpha-glucan, or an insoluble cationic ether thereof, comprising alpha-1,3-glycosidic linkages and having a weight-average degree of polymerization (DPw) of at least about 100. Further disclosed are methods of preparing these compositions, as well as systems for storing and/or moving them.