Can the Can?

Silver color fresh and tasty beer can tops
Written by Ian Boyd

Historically, canned beer has had very bad press. It has either been associated with cheap and nasty product, more suited to tasteless generic and mass-produced brands, or with super-strength “rocket fuel” ciders and lagers consumed by louts or drop-outs on street corners and park benches. On top of that, there is the belief that cans impart an undesirable metallic taste to the contents. So strong have been these notions, that it is widely thought that beer in a bottle is superior on all fronts.

But, aside from the negative images, does beer from a can really taste metallic? After all, beer starts off being mashed in a metal vessel. It is then boiled, fermented and matured in metal tanks before being transported to the pub cellar in metal casks where it is subsequently pulled through metal pipes to your glass in the bar. And how often do you detect any metal impurities in your glorious pub pint?

It turns out that the only reason these days why beer from a can might taste metallic, is if you drink it straight from the can itself, and your lips and mouth are in direct contact with the exterior of the tube. This is never a good idea with any vessel that beer is transported in, if you think about it, not even a bottle. You never know where it has been!

Beer stored inside a can is never actually in contact with any metal. All beer cans, since their introduction in 1935 in the UK by Felinfoel Brewery in Wales, have been specially lined to stop any liquid contact with the metal. Having said that, the coating technologies in those early days was fairly primitive, and there were indeed occasions, albeit only occasionally, where an imperfect lining caused undesirable interactions.

Move on seven decades, and since even before the turn of this century, the materials and technologies used have changed immeasurably. The old style cans, sometimes called ” tin” cans, used to be made from steel which was coated with tin, i.e. tinplate. They were very strong and rigid. Anyone remember trying to squash an old beer can with one hand to prove how macho they were?!

Nowadays cans are fabricated from much lighter aluminium and most casks in use today are also either made from aluminium alloy, or stainless steel. All metal casks AND cans are now coated inside with an impervious polymer lining to inhibit any liquid/metal contact. Beer, after all, is slightly acidic, and readily attacks metal. So, the can is simply a mini cask. It vents when you open it, as does a bottle, and ideally you should quaff the contents after pouring into a well-washed clean drinking glass. Yes, there are those that drink from pewter mugs, but on this occasion, I am not going to go there…

The Sierra Nevada brewery in the USA recently performed a blind sampling with 25 tasters to test if there was any perceived difference between bottled and canned beer. They used four different beers, including their own multi-award winning pale ale. Although only by a small margin, more tasters preferred the canned beer to the bottled product. Slight majority, or not, the main point to be drawn from the experiment is that modern canned beer does not taste any different from bottled beer. More than 500 new breweries in the USA can their beer, while here in the UK, a growing number of breweries (Moor, Beavertown…) are doing the same.

Taste aside, it might be further argued that beer packaged in an aluminium can has other advantages over bottled beer. For example, aluminium cans are significantly lighter than glass bottles and take up less space. It has been estimated that 110 pallets of canned beer take up the same space as 70 pallets of bottles. This makes both haulage and storage of canned beer cheaper due to weight and geometry, and this significantly reduces the carbon footprint involved with transport.

Furthermore, glass is fragile, making bottle handling more difficult and more prone to accidental damage than with cans – not only in the production process, but also in after-sale portability, i.e. shop or brewery to car, or home to picnic, boat or rucksack. Cans are also more acceptable at venues where glass is not, such as sporting or festival venues, beaches, parks etc.

The earliest metal beer cans used had a tubby cylindrical body which narrowed into a neck, and actually had beer bottle-top fittings, known as crown corks! Later models dispensed with the neck and cap and morphed into simpler shaped factory sealed tubes. These required a can piercer, or “church key” that punctured a small triangular hole into the top of the container to release the beer.

By the 1960s, the pull-tab, or ring-pull technology had become widely established, dispensing with the need for can openers. Popular though it was, the discarded ring-pulls led to undesirable levels of littering and for a brief period, push-tabs were briefly introduced. These involved pushing the tab inward into the can to reveal an elongated opening, but although the tabs remained connected, this unavoidably led to safety hazards due to cut fingers from the sharp exposed edges of the opening.

Nowadays we use the “stay-tab”, which functions by externally levering and pushing the tab into the can interior whilst remaining connected. No superfluous littering and no finger damage. Present-day beer cans therefore need NO additional instrumentation to open, unlike bottles, and result in one unit of litter, rather than two.

And while we are on about the physical properties of cans versus bottles, it is worth mentioned thermal conductivity. Heat travels faster through metals than through insulating oxide-based silica bottles. Hence, cans take much less time to cool down to drinking temperature than bottles, should you wish to guzzle your new found purchase a few degrees cooler than the warm climate of a shop shelf.

Moving on to optical properties, as discussed in POV 286, most bottled beer these days is packaged in brown glass which is largely opaque to UV and visible light, and this minimises spoiling of the contents by photochemical “lightstriking”, or “skunking” For example, a 1.8mm thick brown bottle only transmits 5% of the light, where a clear bottle lets through 90% or more. To reduce the transparency even further closer to zero, the darker bottle has to be more than 3.5mm thick, and this increases its weight considerably. With cans, NO light whatsoever can penetrate even the very thin metal, completely eliminating any possible light-induced photochemical reactions within the beer.

In terms of production, with bottling, no matter how well the machinery works, there is never a 100% guarantee that the metal cap fixed onto the glass bottle is completely heremetic (airtight). I’m sure some of us have at least on one occasion opened a bottle to find the contents completely flat or even worse, pungent. And at the other extreme we have the notorious “bottle-bomb”, where caps can explode off the top of the bottle, or worse still, the bottle itself, even without any transport induced hairline fractures being generated, can shatter dangerously under the pressure generated by the yeast working too much overtime.

Then there is the recycling issue. It has been often said that cans are much more environmentally friendly than bottles. Aluminium cans are, after all, the most recycled beverage containers in the world at around 70%. In 2012, 92% of all aluminium beverage cans in Switzerland were made of recycled material and in some areas a used can could end up on the retail shelves within 60 days. By comparison, only 25% of glass bottles are recycled, and since they need to be sorted and processed differently, coloured glass is more laborious and costly to re-process. And unlike with aluminium, which is craved by automobile and aeronautical industries, demand for recycled glass is significantly weaker. Finally, it has been calculated that the energy savings accrued when recycling aluminium are around 96% of the cost of using “new” aluminium, whereas with glass it is only a 26% saving. However, the recycling business is significantly more complex than these numbers indicate, and involve a number of other issues which I hope to re-address in a future article.

So, in terms of the physical, chemical and optical properties of the materials involved, it seems to be a no-brainer that aluminium cans have more than an edge over bottles for packaged beer. The question is, are you, the reader convinced and will you allow these facts to counteract your prejudices?

I reckon that for some, imagery, symbolism and stigma is strong, and it’s an up-hill battle. After all, could you ever imagine a magnum of Moët & Chandon Dom Perignon in a giant can? Or would you prefer to have a gift of 750ml of a 14% bourbon-aged Russian porter in a giant can or a pleasingly shaped bottle? But there again, did your grandfather’s tobacco smoke less well from the old fashioned tin than it does from the plastic pouch it now comes in? Or ask your kids if smarties taste any worse from a party bag than from a cardboard tube…or coke from a plastic rather glass bottle!

“Diner” is a favourite cult film of mine. When Steve Guttenberg’s character, Eddie asks, “When you are making out, which do you prefer, Sinatra or Mathis?”, Mickey Rourke’s character “Boogie” replies, “Presley”.

In a similar vein, when asked if I prefer cans or bottles, I reply “cask”. There is nothing better than going to your local pub and quaffing a fresh pour direct from the cellar.

While an empty firkin (9 gallons) weighs about 10kg (and by proportion an empty kilderkin or kil (18 gallons) weighs around 20kg) it would take approximately 40kg (twice as much dead weight) of glass to carry around the equivalent amount of beer in bottles. And casks that transport the beer from the brewery to your glass have a lifetime of up to 20 years.

So, I suggest, where possible, drink green, drink cask, and keep your pubs open!

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