Fuel flexibility will drive the energy demand in the near future. The use of different syngas compositions from various sources (i.e. coal, food, algae, etc.) will also play a major role in the global fuel mix. However, this contrasts with the experience of several global operators. Instabilities found can range from thermoacoustics, flashback, autoignition and blowoff. In terms of blowoff, the phenomenon is still not entirely understood. As the process occurs, theoretical limits do not match its measured behaviour. One possible explanation could link the stretch of the flame and its recovery with the transient nature of the Central Recirculation Zone (CRZ). This project presents a series of experiments to determine the behaviour and impact on the blowoff process at various swirl numbers, nozzle geometries and gas compositions at same power outputs. The Central Recirculation Zone was measured and correlated to the blowoff phenomenon. A trend was found between the CRZ size/strength, the different compositions of gases used (i.e. CO2 and CH4 content) and the burner nozzle. The results show how the strength and size of the recirculation zones are highly influenced by all these parameters. However, it seems that the CRZ dimensions/strength does not play an important role in the blowoff phenomenon under the conditions studied, whilst the composition of the mixture shows high correlation. Nevertheless, the intensity of the CRZ using these compositions can increase residence time, important for combustion improvement of other blends.