I had an interesting email from a reader: "Without a modern industrial base, how could a brewer capture and contain carbon dioxide. It's simple, fermentation produces CO2. Keep a stopper in the bottle and you have a carbonated alcoholic product. Even Americans know how champagne is made." At least one other response was in the same line, though not quite as condescending.
I guess this is supposed to show how little I know about beer, but as an ex-industrial chemist, I can guarantee it is more complicated. The issue is not the brewing of the beer. It is the storage! Cyrus the Great lived from about 600 BC to 530 BC. There were no beer bottles! Glass was very expensive and would have only been used for ornamental purposes, or for holding djinnis! Cork, which is what stoppers are usually made from, is not native to Persia; it would have to be imported from Southwest Europe or Africa. Rubber would not have been available, either, since it is from Southeast Asia. A different option, a wood dowel wrapped in leather, is not something that will hold pressure for any length of time. Next, during the production of beer, the carbon dioxide is allowed to bubble off; most (not all) modern beers have the carbonation added during the final stages of production. Making beer was a large-scale enterprise and it was stored in large clay pots, not something you could put a stopper in. Other containers included wooden casks, not a vessel capable of long-term high-pressure storage. Glass containers did not become common until glass-blowing machinery was invented in 1880. The same applied to metal kegs - the first large scale production of aluminum didn't occur until 1886. Industrial-scale production of carbon dioxide didn't occur until the mid-1800s. So, even though I'm an American, I think I know how beer is made, especially since I worked in a brewery one summer when I was in college.