A partial oxidation burner is introduced as a cleaning system for the tar content of (bio) fuel. The low-swirl ( S approximate to 0.2) flow at the burner outlet is studied using Stereo Particle Image Velocimetry. After calibration the experimental setup is capable of resolving all three velocity components. The presented results show that the averaged coreflow vortex has the characteristics of a solid body rotation. After leaving the burner outlet the swirl number rapidly decreases from about 0.2 to 0.07. The turbulent kinetic energy has also been resolved and shows that the fluctuations are concentrated around the flow center line at levels of 5-10%. The velocity field is homogeneously mixed at about 40 mm above the burner outlet.