Entrained flow gasification is a promising way to convert biomass into valuable fuels and chemicals. Residues formed during gasification of biomass have considerable effects on process efficiency and syngas quality. In the current work, residues from wood powder gasification were collected from two syngas coolers at different temperature levels in an electrically heated small-scale 15 kW entrained flow gasification reactor setup operating with air as gasification agent at a stoichiometry of 0.55 and a setpoint temperature of 1160 °C. The residues were characterized by thermogravimetric analysis to study general decomposition properties and their reactivity toward CO2. The morphology, microstructure and chemical composition of the collected residues were examined by scanning electron microscopy (SEM)/energy dispersive X-ray spectrometry (EDS). It was found that the properties of the residues collected from the two coolers are very different. The differences are mainly related to the transformation and fate of products from decomposition and gasification of the wood particles at local temperature and concentrations conditions in the two coolers, and partly related to flow conditions and deposition history at the different physical locations. SEM/EDS analysis results show that the residues mainly contain a mixture of partially unconverted fuel particles, carbon rich chars and condensed organic and inorganic compounds, which have different visual appearance, structures and compositions in the residues collected from the two coolers. The general reactivity of the residues from the two coolers were in the same order. But, because of mainly different temperature histories and physical locations, their reactivities are still evidently different, which is associated to their resulting different physio-chemical properties.