Beer bottles are a common thing in life. However, I wonder if you have noticed a detail: most beer bottles are green, and there are very few brown, blue and colorless beer bottles. Today, let Xuexuejun explain to everyone why most beer bottles are green.
- From technical limitations to tradition
Although beer has a very long history, putting beer into glass bottles has only been around since the mid-19th century.
Initially, people even thought that glass was green. At that time, not only beer bottles, but also ink bottles, paste bottles, and even window glass were slightly green. This is because the initial glass manufacturing process was not very sophisticated and it was difficult to remove impurity ions such as ferrous ions in the raw materials, so the glass produced was green.
Later, the glass manufacturing process became advanced and these impurities could be removed, but the cost was too high, and people found that green wine bottles could delay the taste of beer. Therefore, at the end of the 19th century, people specialized in producing green glass bottles to hold beer. The tradition of green beer bottles also That’s why it was retained.
Later, people would add ferrous oxide and chromium oxide as dyes to the glass to make it look greener.
- Take back the country from the brown bottle
In the 1930s, people accidentally discovered that the taste of beer in brown bottles did not deteriorate after being left for a long time. On the contrary, brown bottles can better avoid the impact of light on the beer.
Beer exposed to sunlight can develop a foul odor. Research has found that the culprit behind the odor is isoalpha acids in hops. Under light conditions, the bitter component tricone in hops will help the formation of riboflavin. At the same time, under light conditions, the isoalpha acid in beer will react with riboflavin and decompose into a compound, which will smell bad.
The use of brown bottles or some dark bottles can absorb most of the light, which can hinder the occurrence of this reaction. Therefore, more and more beers were used in brown bottles.
However, after World War II, there was a period of time when the supply of brown bottles in Europe was in short supply, forcing some well-known beer brands to return to using green bottles to hold beer. Due to the high quality of these brands of beer, green bottle beer soon became synonymous with high-quality beer. Many breweries followed suit and started using green bottles.
With the popularity of refrigerators and the advancement of sealing technology, using brown bottles does not bring better quality than using bottles of other colors, so green beer bottles are booming again.
- How are colored glass bottles made?
So how do those blue or colorless beer bottles we see now change the color of green glass?
After people revealed the secret of green glass, they worked hard to eliminate the green color in the glass and decolorize the glass. Glass decolorization is divided into chemical decolorization and physical decolorization.
Chemical decolorization generally uses the oxidation of a decolorizing agent to eliminate the color of glass contaminated by organic matter, and convert low-valent iron oxides with strong coloring ability into ferric iron oxides with weak coloring ability. Physical decolorization generally involves adding a certain amount of colorant that can produce complementary colors into the glass.
In the same way, colorless glass can also be made into colorful stained glass by adding various compounds. For example, the blue glasses worn by steelworkers are made by adding cobalt oxide to the glass; purple glass contains manganese dioxide; and the famous gold-red glass is usually made of gold compounds as dyes.
Today’s technology is so advanced that beer bottles can even be made into colors, but everyone has already assumed that beer bottles are green. Using green wine bottles is a tradition and a sentiment.
