I live and work in Berlin for years now, working in startups, and I haven't met anybody that (openly) uses anything harder than tobacco or coffee, nor I met anybody who said they knew somebody to do that.

Beer is common after work, once in a while. However, what you describe is definitively not normal. Not that I find that problem, or high-risk, or anything - it's just the fact that it would just surely catch attention if anybody from my work environment (30+ close coworkers) notice somebody like you're describing.