Isomalt is an odorless, white, crystalline, and low-hygroscopic substance. Isomalt tastes like sugar, but it is less sweet. In a 10% solution, its sweetening power is 50–60% that of sucrose. Although it has less sweetening power, it has a similar sweetness profile.
One of the advantages of using isomalt is that it can be combined with intense sweeteners to achieve various sweetness profiles, thus optimizing sweetness without masking flavor, which is a limitation of some other sweeteners. Furthermore, isomalt blends well with many flavors, including fruity, menthol, and minty. Isomalt's negative heat of solution (−39.4 kJ kg−1) results in a cooling effect lower than all other sugar replacers. Therefore, products such as isomalt-containing chocolates have no unpleasant cooling effect in the mouth.
Standard isomalt has a solubility of 24 g per 100 g of solution at 20 °C, increasing at higher temperatures. Based on its sorption isotherm, an index of raw material hygroscopicity, isomalt is a very stable ingredient. It absorbs virtually no water up to a relative humidity of 85% at 25°C.