Cans vs. bottles: Further perspective from Steam Whistle Brewing

steam whistle

On Thursday, in a post I wrote about Nickel Brook’s Naughty Neighbour coming to can format, I offered up a bit of my own opinion along with the news.

In addition to a tangent about unions and my excitement that a great session ale was coming to a larger format, I offered up my two cents on why I prefer beer in cans over bottles. Among the insightful, humorous, and signature delightfully entertaining points I made in that post were my observations that cans offer the best protection against both light and oxygen and therefore offer the freshest possible means to enjoy a beer. 

Today, in response to my points, I received an email from Sybil Taylor, who is the Communications Director of Steam Whistle Brewing. Incidentally, she’s also married to one of the guys listed as a co-founder and she was the brewery’s first official employee. Sybil took some issue with my assertion that bottles can’t offer as fresh a beer, notably given Steam Whistle’s particular attention to detail in this area. In order to present both sides of this argument, with Sybil’s permission, I’ve opted publish the email she sent me. 

I wanted to write to set the record straight on this fact – at least as far as Steam Whistle is concerned. I’m not certain if what I’ll explain is the same for other brewers but in our case, our bottles do probably offer the best form of beer packaging out there. Our cans would run a very tight second.

We’ve invested in Krones state-of-the-art fillers for both our canning and bottling lines. They are essentially the “Mercedes” of beer equipment and we’ve invested this way to help preserve the good work done by Marek [Mikunda, Steam Whistle’s Brew Master — BJ] and his team in the Brewhouse and cellars. Our beer sits in Bright Beer Tank after filtration with about 10 parts per billion oxygen (oxygen being the evil-doer in terms of food/beverage spoilage, or at least deteriorated taste and shelf life), so virtually oxygen-free.

When we bottle our beer, we run around 14 parts per billion oxygen on average, which is downright remarkable. Krones uses a double evacuation process, blasting C02 into the bottle twice to flush out any air/oxygen before the beer is filled, and then we fob with a sterilized tiny stream of hot water to cause the beer to bubble up out of the bottle top, pushing any air out of the headspace in the bottle split-seconds before capping. This fobbing creates negative pressure and thus the vacuum “pop” sound you hear when you uncap a bottle of beer. Our heavy-duty signature green glass bottle allows us to crimp the cap very hard down onto the bottle rim, thus offering a superior seal. We probably err more on the side of too tight a crimp, rather than too loose. Then we pack our bottles in an enclosed beer carton (unlike many imports in an open basket carrier)[Take that, Corona! — BJ] to protect our beer from UV light.

When we can our beer, we run around 30 parts per billion in oxygen, which is still exceptionally good (our quality assurance team tells me that you won’t begin to run into issues with oxygen until about 100 ppb). Because cans arrive at any brewery as an open-top cylinder, this wide-mouth package always lets  a little more oxygen into the headspace at point of filling, even with the Krones pre-filling CO2 evacuation and fobbing. Such a large top lets more air in, it’s unavoidable. But you are correct that once it goes through the seamer, a can has a really tight seal, and it is a solid package wall so [it is] free from UV light damage which will help downstream.

I want to emphasize that other brewers may not have the same results we do as far as oxygen PPB. The sophistication as well as the speed of the packaging lines would have a big impact on this and I’m very certain that we would stand out as far as our quality assurance initiatives.

I hope this information helps to shed some light on the issue [. . .]


Sybil Taylor, Communications Director
Steam Whistle Brewing


8 thoughts on “Cans vs. bottles: Further perspective from Steam Whistle Brewing

  1. While I admire Steamwhistle’s efforts to reduce the amount of dissolved oxygen in their packaging, the green glass bottles are still a fatal flaw. They may be shipped in UV-resistant boxes, but the second they get unpacked and are put in a bar’s fridge, or a customer’s fridge at home, they’re being exposed to UV light. I’ve had far too many skunked bottles of beer in green bottles, including Steamwhistle.

    1. Hey Eric, we agree. Who wants to drink skunky beer!? Education is key. Our cases are all marked “Store in a dark, cool place” and we visit bars/restos to change to non-UV light bulbs, to add light-filters to the glass fridge doors and to educate. The killer is on patios where everyone’s beer in a glass or bottle (regardless of colour) gets skunked eventually. Cans are best in summer or outdoors.

      1. Thanks for the response, Sybil. I’m glad to hear you care so much about your product. Impressive that you are making the effort to invest in UV-blocking filters and bulbs for bars. Cheers!

  2. This fobbing creates negative pressure and thus the vacuum “pop” sound you hear when you uncap a bottle of beer
    This part made me scratch my head. The dissolved CO2 will seek an equilibrium between beer and headspace in the bottles. And while fobbing may transiently create a vacuum, the headspace of any carbonated beverage will rapidly equalize with the dissolved CO2, and will be pressurized (about 30PSI at room temp, less than half that at fridge temp).

    That hiss is pressure, not vacuum, unless steamwhistle has found a way to undo Henry’s law.

    1. Thanks for pointing out my misinformation here. I spent some time with our Assistant Brewmaster to get another science lesson. Here’s a summary: the bottle filling process involves first drawing a vacuum on the bottle to evacuate any oxygen present followed by pre-pressurizing it with CO2. This process occurs twice on our Krones filler, and is known as “double pre-evacuation”. This process is capable of delivering bottles with incredibly low levels of oxygen. This is not possible in cans due to the flimsy nature of aluminum cans, which would simply implode under vacuum conditions. As a result, small amounts of air mix and dissolve into beer during filling. To conclude, in terms of oxidation limited shelf-life, the bottle is best. As for the pop sound on opening, you were right of course: The CO2 concentration of Steam whistle is about 2.75 vol./vol. This means for every liter of beer there is 2.75 l of CO2 forced into solution. This extra CO2 is what gives rise to all the tiny bubbles in carbonated beverages as the CO2 comes back out of solution, escaping as a gas again. In a sealed container, this results in a buildup of pressure (until it is opened). The “pssst” you hear upon opening a beer is excess CO2 pressure being released.

  3. I admire Steam Whistle for their commitment and dedication to their branding. I was at one of the very first launch events they had, many many years ago. While listening to Cameron Heaps tell his 3FG story, we had free samples of their beer. Sadly they were slightly skunked back then…yet at the time, even that was better than most brews in Toronto.
    I was certain that Steamwhistle was simple always skunked as every time I had it over the years, it was slightly off. We’re talking more than a decade of varying levels of skunked experiences.
    It wasn’t until about 3 years ago that I had a Steamwhistle on draft and was certain it was the wrong beer. It was crisp, flavourful, delicious. Unlike anything I had ever had in a bottle. Then I picked up some cans a couple of fresh cans a couple of years ago and they were almost as good.
    I don’t know when this magical krones filler came into use, but for me, I have steered clear of SteamWhistle bottles for many years.

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