I work for a company that manufactures equipment that is widely used in the brewery industry. Is it permissible to sell to these industries and visit the plants for surveys? May Allah reward you.

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ʻalayhi wa sallam, is His slave and Messenger.

There is no harm in working in the mentioned company in lawful tasks, including the manufacture of equipment that may be used for lawful or unlawful purposes. There is no harm as well in visiting the plants for the purpose of conducting surveys and the like as long as the person does not engage directly in unlawful activities or provide direct or intentional help in committing them. There is no harm in this based upon the basic principle that all work is permissible unless proven otherwise.

As for selling the equipment that may be used in the brewery industry, it is only prohibited to sell such equipment to someone if it is known that he will certainly or most likely use it for making beer, because the means are subject to the same ruling as the ends; whatever is used as a means to the unlawful is itself unlawful. The scholars stated that it is forbidden to sell grapes to a person who would squeeze them to make wine because this constitutes helping him in committing what Allah has prohibited; Allah, the Exalted, says (what means) {Help you one another in virtue, righteousness, and piety but do not help one another in sin and transgression.}[Quran 5:2]

Allah knows best.