When alcohol was illegal there was a lot of “cutting” involved in illicit alcohol and crappy quality control on what was put in alcohol things like methanol were put in.
When you take any product or service into the black market the quality and thus the safety of the product goes way down as people selling it don’t give a crap about your safety because the producsers are far more disconnected from the users. Because if the users know who was smuggling/making the drug the supply would be quickly cut off.
Yes but a lot more people also knew how to make various alcoholic beverages safely too, because they learned from their parents who learned from their parents how to make certain alcoholic beverages from the old country. Wines, brandies, other certain liquors were often made by families as just part of something the family did.