Why are beer bottles green?

The history of beer is very long. The earliest beer appeared around 3000 BC. It was brewed by the Semites in Persia. At that time, the beer did not even have foam, let alone bottled. It is also with the continuous development of history that in the mid-19th century, beer began to be sold in glass bottles.
From the very beginning, people subconsciously think that glass is green – all glass. For example, ink bottles, paste bottles, and even windowpanes are all green, and, of course, beer bottles.
Because the initial glass manufacturing process was immature, it was difficult to remove impurities such as ferrous ions in the raw materials, so most of the glass at that time was green.
Of course, the times are constantly developing, and the manufacturing process of glass has also improved. When the impurities in the glass can be completely removed, the beer bottle is still green. Why? This is because the process of completely removing impurities is too expensive, and such a mass-produced item like a beer bottle is obviously not worth the huge cost. And most importantly, green bottles have been found to delay beer staleness.
That’s good, so at the end of the 19th century, even though it was possible to make clear glass with no impurities, people still specialized in green glass bottles for beer.
However, the road to overlording the green bottle does not seem to be so smooth. Beer is actually more “afraid” of light. Long-term sunlight exposure will lead to a sudden increase in the catalytic efficiency of the bitter ingredient in beer, oxalone, thereby accelerating the formation of riboflavin. What is Riboflavin? It reacts with another substance called “isoalpha acid” to form a harmless but bitter-smelling compound.
That is to say, beer is easy to stink and taste when exposed to sunlight.
Because of this, in the 1930s, the green bottle had a rival – the brown bottle. Occasionally, someone discovered that using brown bottles to pack wine can not only delay the taste of beer more than green bottles, but also block sunlight more effectively, so that the beer in the bottle is better in quality and taste. So later, brown bottles gradually increased.