Beer Cans: Safe Drinking Vessels?

There are several factors to consider when it comes to the safety of drinking beer from a can. Beer cans are usually made of aluminium and plastic, with the outside made of aluminium and a thin food-grade plastic film on the inside to protect the beer from contact with the aluminium. While aluminium is toxic to health, the plastic film inside the can is also an endocrine disruptor and has been associated with a range of health issues.

Beer cans block light, preventing a skunky aroma and taste

Beer cans are safe to drink from, and they have several advantages over glass bottles. One of the most important benefits is that they block light, preventing a skunky aroma and taste.

Beer is susceptible to "skunking" when it is exposed to light, particularly light in the blue and ultraviolet range (400-500 nanometers in wavelength). This exposure to light causes a chemical reaction in the hops, which are naturally light-sensitive. The result is the creation of "skunky thiol," which is chemically similar to the compound found in a skunk's spray.

Cans offer perfect opacity, completely blocking out light and protecting the beer from skunking. On the other hand, glass bottles, even amber or brown ones, only filter out some of the light. While they block most ultraviolet light, they still allow some visible light to pass through, which can trigger chemical reactions in the beer over time.

By using cans, brewers can ensure that their product is not affected by light, maintaining the intended flavour and aroma of the beer. This is especially important for beers with higher hop contents, as hops are the ingredient most susceptible to light-induced changes.

In summary, beer cans are an effective barrier against light, helping to prevent the formation of undesirable compounds and preserving the quality of the beer. This is one of the key advantages of canned beer over bottled beer, along with ease of storage, transportation, and recycling.

Aluminium is toxic to health

Aluminium production is also dangerous for workers. The International Agency for Research on Cancer (IARC) has classified the process of aluminium production as a definite (Group 1) human carcinogen, citing an increased risk of lung and bladder cancer in aluminium workers.

Aluminium cans are lined with epoxy that contains bisphenol A (BPA), a chemical that keeps food from reacting with aluminium. BPA is a well-known toxic chemical and is the most produced synthetic chemical, with some experts estimating that 600 million tons are made annually. BPA has been linked to a range of health issues, including cancer, obesity, heart disease, diabetes, reproductive issues, and irregular brain development in children. It is an endocrine-disrupting chemical, meaning it likely causes hormonal damage at extremely low levels.

Research has shown that BPA can leach from can linings into food and beverages. A 2011 study found that a group of volunteers who consumed canned soup for five days had a more than 1000% increase in urinary BPA concentrations compared to when they consumed fresh soup. Another study by Korean researchers found that when subjects drank canned soy milk, their urine BPA levels surged by 1600%, and their blood pressure rose significantly, compared to when they drank from bottles.

While the Food and Drug Administration (FDA) has deemed BPA safe at current levels found in foods, this stance is highly controversial among scientists, with roughly 1000 published studies finding that low-level exposure to BPA can lead to serious health issues.

The plastic film inside the can is an endocrine disruptor

Bisphenol A (BPA) is a chemical commonly used in epoxy resins that line aluminium cans to prevent food from reacting with the metal. It is well-established as an endocrine-disrupting chemical, meaning that it likely causes hormonal damage at extremely low levels. In 2017, the European Chemicals Agency classified bisphenol A as a substance of very high concern. This classification reinforced the use of alternatives, mainly bisphenol S (BPS). However, researchers in Toulouse have shown in a study that BPS, a substitute for BPA, persists longer in the body and at higher concentrations in animals, raising doubts about the consequences for human health.

According to INERIS (the National Institute for Industrial Environment and Risks, France), the transparent film lining the inside of beverage cans is made of plastic based on BPA. Banned in France in 2015, it is still authorised in Switzerland and the United States.

The Food and Drug Administration (FDA) has given BPA a tentative thumbs-up, pronouncing it "safe at the current levels occurring in foods." However, this decision is highly controversial among scientists, as roughly 1,000 published studies have found that low-level exposure to BPA can lead to serious health problems, including cancer, insulin-resistant diabetes, obesity, and attention-deficit disorder.

One such study, published in the Journal of the American Medical Association, found that a group of volunteers who consumed a serving of canned soup each day for five days had a more than 1,000% increase in urinary BPA concentrations compared to when they consumed fresh soup daily for five days. Another similar study by Korean researchers found that when subjects drank canned soy milk, their BPA levels surged by 1,600%, and their blood pressure rose significantly compared to when they consumed soy milk from bottles.

While BPA-free can linings exist, they are only approved for low-acid foods like beans. For high-acid substances like beer, there is currently no approved alternative.

Beer cans are more outdoor-friendly

Another advantage of beer cans is their lightweight and stackable nature, which makes them easier to transport and store. Whether you're hiking up a trail or packing a cooler for a picnic, cans are a more compact and portable option. They also have a smaller carbon footprint during transportation and distribution because of their lighter weight.

Additionally, beer cans are better at blocking light and oxygen, both of which can negatively impact the taste and quality of beer over time. The opacity of cans helps protect the hops from light, preventing the beer from developing a skunky aroma and taste. Furthermore, cans are more effective than bottles at keeping oxygen out, which can cause beer to age and develop unpalatable flavours.

While some people may prefer the sensory experience of drinking beer from a glass, cans offer a more practical and durable option for outdoor settings. They eliminate the risk of broken glass while still providing a refreshing beer-drinking experience. So, if you're planning to enjoy a beer in the great outdoors, choosing a can over a bottle is a wise and safer choice.

Beer cans are more environmentally friendly

The environmental benefits of beer cans become more apparent when considering the impact of cross-country transportation. The average beer can weighs less than an ounce when empty, while an empty bottle weighs close to 6 ounces. This weight difference contributes to lower overall greenhouse gas emissions during transportation as heavier items require more fuel to transport. According to a breakdown by Germany's Wuppertal Institute, once a cross-country truck journey is factored in, a glass bottle emits 20% more greenhouse gases than a can.

Additionally, the process of mining bauxite, the raw material for aluminium, while environmentally damaging, is not as energy-intensive as glass bottle production. Although glass is made from more easily accessible silica, the mining process for bauxite is less intrusive and does not require tunnels. However, bauxite mining uses heavy equipment and generates significant dust, impacting the local terrain and air quality.

Beer cans also have a more promising recycling rate than glass bottles. Approximately 45% of cans are recycled, compared to around 25% of bottles. This is partly due to consumer misconceptions about glass biodegrading in landfills, leading to glass bottles being tossed into regular trash. Additionally, there is a weaker demand for recycled glass, with 90% of it ending up back in bottles or similar containers.

In summary, while both beer cans and glass bottles have their environmental drawbacks, cans emerge as the more environmentally friendly option due to their lighter weight, higher recycling rates, and lower overall environmental impact during transportation.

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