Glucose syrups are all very soluble in water, the limiting factor being the viscosity of the solution, particularly with the lower DE materials. There is little difference in the overall solubility of different syrups but a significant difference in the rate at which the solid materials dissolve. This is of course particularly important for those products sold commercially as powders, typically below about 50 DE. Water temperature, rate of stirring and particle size are all important factors which will affect the rate of dissolution but these being equal, the solubility rate is directly related to the DE of the material. Typical results are shown in the table below for products below 50 DE (Kearsley and Birch, 1975). Syrups below about 60 DE show little tendency to crystallize on storage even if storage temperatures fall. Above 60 DE dextrose may crystallize from the solution if storage temperatures fall. The manufacturer and consumer of the glucose syrup, therefore, have the dilemma of storing at high temperatures and risking browning or storage at lower temperatures and risking crystallization. Obviously, a compromise is reached and high DE syrups are typically stored at 45-55°C.
| Dried glucose syrup DE | Solubility rate (% min) |
| 15 | 1.8 |
| 19 | 2.1 |
| 25 | 2.3 |
| 33 | 3.0 |
| 37 | 2.9 |
| 42 | 2.8 |
| 49 | 3.5 |