What would be the maximum concentration of alcohol in beverages that are naturally fermented?

Dear Student,

Here is the answer to your question,

The alcoholic strength of beer is usually 4% to 6% alcohol by volume

In beer alcohol content varies from  9%–16%

Unsweetened, distilled, alcoholic beverages ( known as spirits) that have an alcohol content of at least 20%

Hope this helps,

Best wishes !!