A study was conducted to demonstrate the logical impact that the synthesis conditions can have on the properties of UiO-66. Seven potential pitfalls regarding sample ideality were investigated. Five different BDC:Zr ratios were also synthesized on different temperatures. Moreover, the effect of DMF washing and methanol exchange procedures was assessed. It can be seen that the thermal stability of UiO-66 is dramatically and systematically improved by increasing the synthesis temperature. The PXRD pattern of UiO-66-100-2:1-2DMF is already somewhat affected by treatment at only 200°C. Treatment at this temperature typically resulted in 70% of the original sample mass being retained. Regarding the other synthesis parameters investigated, it was found that the BDC:Zr ratio had little effect on the thermal stability of the materials, while stability decreased with increasing extent of washing.