I was taught this in my college history classes in reference to cholera outbreaks in the USA in the 1800s. We were taught people use "half beer" which was 50/50

I was taught this in my college history classes in reference to cholera outbreaks in the USA in the 1800s. We were taught people use "half beer" which was 50/50 mixed with water, as a safety measure. I have no idea if it is real. It was just what the book and professor said.