Can black coffee and a shower help you sober up?

Consuming black coffee alone will do little to reverse alcohol's effects. Although caffeine might heighten your alertness, it won't get rid of the alcohol in your system. Alcohol use can impair judgment and decision-making, so replacing one intoxicant with another is not wise.

A shower

Taking a cold shower will not eliminate alcohol from your body. Alcohol is broken down and eliminated from the liver, and its concentration in the body cannot be changed by an external water source. Taking a shower may help some people feel refreshed and alert, but it does not remove alcohol from the bloodstream or treat alcohol impairment.