An NMR nutation expt. for quadrupolar nuclei developed by Samoson and Lippmaa (1983) was applied to 27Al spins in the H-ZSM-5 zeolite catalyst. The 27Al nutation spectra change with H2O content in the pores of this zeolite, from which it can be concluded that in the hydrated state many 27Al nuclei are in highly sym. surroundings. On dehydration, the quadrupole interaction of these spins increased drastically, beyond detection. A 2nd type of 27Al spin with an intermediate quadrupole interaction that hardly changes on hydration/dehydration was detected.