Beside MOBIL processes or catalytic cracking, conversion of ethanol to hydrocarbons (ETH) is an example of the well-known family of hydrocarbon pool processes. From the large variety of hydrocarbon products formed over the porous zeolite ZSM-5 questions arise not only on the preferred types of conversion reactions but also on their major location on the zeolite crystal during progressing catalyst coking. A microcrystalline, aluminum-rich industrial HZSM-5 zeolite (Si/Al = 12 - 15) was post-synthetically treated in two combinations to force changes in materials and catalytic properties to reveal structure-durability and structure-selectivity relations. From mechanistic consideration of dehydration and following build-up and cracking reactions the overall selectivity towards higher build-up products correlates with the accessibility of the pore system, (i) Pore cleaning in combination with dealumination increases the accessibility of the zeolite pores and supplies a good transport of bulkier liquid phase products out of the pore channels, (ii) Artificial pore blocking by silicate impregnation and subsequent pore cleaning initially reduces product forming tendencies to higher hydrocarbons in gas phase. Additionally, xylenes reveal an inclusion / exclusion of external sites by slightly preferred formation of sterically overdemanding m/o-xylene or matching p-xylene compared to the pore dimensions. In conclusion, tuned shape selectivity and isomerization at the pore exit and the external surface seems obvious.