Walk into any pub and order a pint of Guinness, and you’ll witness a mesmerizing ritual. The bartender pulls the tap, fills the glass two-thirds full, then sets it aside to settle before topping it off with that iconic creamy head. But crack open a can of Guinness at home, and something magical happens without any theatrical waiting period. Pour it out, and you get that same cascading foam effect that made the beer famous.
But how is it done? It’s all thanks to a tiny little device that is affectionately known as The Widget.
Beer Engineering
In 1959, draught Guinness diverged from other beers. The pints served from the tap at the pub were charged with a combination of nitrogen gas and carbon dioxide, rather than just carbon dioxide alone. Nitrogen is less soluble in beer than carbon dioxide, and low temperatures and higher pressures are required to get it to stay in the fluid. Charging the beer in this way, and then forcing it through a tap with a restrictor plate with many fine holes, allows the pouring of a beer with small, fine bubbles. This is what gives Guinness its signature smooth, creamy texture and characteristic dense head. The lower carbon dioxide level also contributes to the flavor, removing some of the sharp taste present in regular carbonated beers.
When Guinness started using the nitrogenation method, it quickly gained popularity and became the default way to serve the draught beer. The problem was that it wasn’t initially practical to do the same for bottled Guinness. Without being poured through the fine holes of a special tap under pressure, it wasn’t possible to create the same foamy head. Bottled Guinness thus remained carbonated in the traditional manner, and it was thus very much unlike the draught beer served at the pub. The desire was to produce a better version—”bottled draught Guinness” was a term often bandied about. The company experimented with a variety of methods of serving nitrogenated Guinness from a bottle or can. It even sold some bottles with a special “initiator” syringe to generate head in select markets, but it was all too clumsy to catch on with the beer drinking public. A better solution was needed.
The modern widget was developed as the technological solution to this fundamental problem in beverage physics. Guinness tackled this challenge by essentially putting a tiny pressure vessel inside the larger pressure vessel of the can itself. The widget is a small plastic sphere, hollow inside, with a tiny hole on the surface. The widget and beer are placed inside the can on the production line. Liquid nitrogen is then added, before the can’s lid is sealed. The can is then inverted as the liquid nitrogen quickly boils off into a gas. This effectively fills the widget with gaseous nitrogen under pressure, often along with a small amount of beer. It’s a charged pressure vessel lurking inside the can itself.
The magic happens when the beverage is served. When you crack open the can, the pressure inside drops rapidly to atmospheric pressure. The nitrogen under pressure in the widget thus wants to equalize with the now lower-pressure environment outside. Thus, the nitrogen sprays out through the tiny hole with tremendous force, creating countless microscopic bubbles that act as nucleation sites for the rest of the nitrogen dissolved in the surrounding beer. As the beer is poured into a glass, a foamy head forms, mimicking the product served fresh from the tap at the local pub.
Today’s widget, first marketed in 1997, is the floating sphere type, but the original version was a little different. The original widget launched in 1989 was a flat disc, which was mounted in the bottom of the can, but fundamentally worked in the same way. However, it had a tendency to cause rapid overflowing of the beer if opened when warm. The floating spherical widget reduced this tendency, though the precise engineering reasons why aren’t openly explained by the company. The fixed widget actually had a surprise return in 2020 due to COVID-19 supply chain issues, suggesting it was still mostly fit for purpose in the brewery’s eyes.
The key to the widget’s performance is in the filling and the construction. It’s important to ensure the widget is filled with pressurized gas, hence the inversion step used in the filling process. If the pressurized nitrogen was allowed to simply sit in the empty space in the top of the can, it would just vent out on opening without making any head. The orifice size on the widget is also critical. Too large, and the pressure equalizes too quickly without creating the necessary turbulence. Too small, and insufficient gas and beer volume flows through to generate adequate nucleation. The widget as it stands today is the result of much research and development to optimize its performance.
Further different widget designs have emerged over the years. The company had mastered draught Guinness in a can, though it needed to be poured into a glass to be drank properly. The company later looked to create draught Guinness that could be drank straight from the bottle. This led to the creation of the “rocket widget.” It worked largely in the same way, but was designed to float while remaining in the correct orientation inside the neck of the bottle. Fins ensured it wouldn’t fall out of the bottle during drinking. It would charge the beer with bubbles when first opened, and continue to boost the head to a lesser degree each time the bottle was tilted for a sip.
Guinness could have left this problem unsolved. It could have remained a beautiful tap-based beer, while selling its lesser carbonated products in bottles and cans for home consumption. Instead, it innovated, finding a way to create the same creamy tap-poured experience right out of the can.
The next time you crack open a widget-equipped can and watch that mesmerizing cascade of bubbles, you’re witnessing a masterpiece of beverage engineering that took years to perfect. It’s a reminder that sometimes the most elegant engineering solutions hide in the most ordinary places, waiting for someone clever enough to recognize that a tiny plastic ball could revolutionize how we experience beer outside the pub.
But why? What’s the need for that kind of stupid, consumerist ritual? At home when I drink Żubr beer I just open a can and drink it. No need to pour it into a glass. Beer is all about alcohol and taste, not watching foam like it’s some piece of abstract art.
Nitrogen, as the article itself notes, changes the texture and flavor of the beer, compared to using carbon dioxide, but there are difficulties in having the nitrogen knocked out of solution in a reliable, repeatable manner. Being able to knock the dissolved Nitrogen out of solution in a reliable manner produces a reliable result, that result is designed to mimic the effect of a tap. This texture directly effects the flavor.
Full disclosure, however, I’ve never been a big fan of Guinness myself, but I can respect the engineering that went into replicating the (IMHO superior) texture of tapped Guinness.
Considering Zubr has a 3 star review on Untapp’d, I’m going to guess you’re less drinking for flavor, and more for effect; to each their own.
Yup. I’ve definitely noticed the effect in carbonated drinks vs nitrogen-ed drinks. Diet Coke has a sharp acidic feel. If you let the Co2 bubble off, the bite goes away. Nitro cold brew is bubbly but smooth right out of the can.
Similarly people taking acetazolamide (say for rapid altitude aclimiazation) as well as the usual diuretic effect will notice the change in carbonated beverages as it inhibits carbonic anhydrase and stops the zing on your tongue.
I’ve heard it called champagne blues.
And presumably nitrogen is not affected by this!
“Beer is all about alcohol and taste” and “Żubr beer” in the same sentence, good one.
And is is not a ritual, humans taste mostly via the nose, so if you drink beer from a can/bottle you will taste it less because less air born stuff gets into your noose. You might prefer it because a beer like Żubr will simple taste worse from a glass because more of it “amazing taste” gets into your nose.
Because I feel like it. Buzz off.
Call me crazy, but the bottles taste worse than the cans. Not everything needs it though. I’m guessing from another comment, Żubr seems to be like Pabst Blue Ribbon. I don’t need a widget to enjoy a cheap beer.
Reading this a few streets over from where it’s made, thanks for linking to the article about the plunger and the Guinness Light, didn’t know that those were the ancestors of the widget. Unfortunately it still tastes like beer.
I’d just like to suggest the alcohol-free Guinness. It’s actually quite good, and the canned variety does indeed have a widget.
^ This. It is good!
Regular Guinness is mediocre, at best.
It’s the American Budweiser of stouts.
Drink ANY micro-brewed stout, much, much better.
Can’t imagine the kinderbeer version is worth drinking.
Some micro brews are better and some are worse, all depends on your taste.
HaHa.
alaska brewing has a good stout. better than guinness.
I’ve had the “zero” alcohol Heineken and Stella. They’re pretty good too.
I’d rather have a nitrogenated cappuccino without milk or sugar than a non-alcoholic Guinness. The taste is the same, but at least I’m being honest and not pretending I’m drinking beer.
discovering i actually kind of like seltzer water led me to open my mind to a lot of these ‘hop tea’ and ‘alcohol-free beer’ sort of beverages. and if you’re desperate for a novelty like i am then you could definitely do worse! there’s even a ‘wheat soda’ that i guess is popular in india and mexico??
if i was to suggest a ‘see also’ for canned guinness with a widget, i would recommend boddingtons
I think the foam is the thing I like the least. Would rather just drink the beer, although give me a Belgian Ale every time…
Great piece! Was confused at first by the definition of widget though. In a business sense, the widget has a different meaning and I was half expecting this story to be about math, and how using a generalized value somehow changed beer delivery. Like how the wooden pallet revolutionized shipping. Was a fun surprise to learn of one more definition of the word widget. Thanks for sharing
Guinness has also released a non widget nitrogen infused can which you use a clip on ‘nitrosurge’ device, I think it just has a pizo speaker that buzzes the nitrogen out every few seconds. You can also put a glass of Guinness in an ultrasonic cleaner with a little bit of water underneath to get the nitrogen out to make a creamy head :)
What I don’t understand is how and why the N goes into the widget rather than “simply sit[ting] in the empty space in the top of the can [which a moment before was the bottom]”.
I’d guess it does both. It fills the empty space and the widget. When you open the can, the gas in the empty space vents out right away, but that in the widget bubbles out more slowly. That’s my guess, anyway.
Thank you, I guess that’s the only way it makes sense. Your answer was helpful.
The answer “As explained twice in the writeup, the can is inverted on the filling line after the nitrogen is added. Instead of the nitrogen staying at the top of the can it travels to the bottom where the widget sits and fills it” was not helpful, not least because it doesn’t reflect that the bottom becomes the top and the top becomes the bottom, as explained once in the question.
As explained twice in the writeup, the can is inverted on the filling line after the nitrogen is added. Instead of the nitrogen staying at the top of the can it travels to the bottom where the widget sits and fills it.
the widget is inserted at ambient pressure. then the liquid nitrogen is added. then the cans/bottles are sealed. as the nitrogen boils off in the can, it increases the pressure, which forces nitrogen into the beer and the beer into the widget. the raised bottom in the bottle/can will keep the widget below the gas line so the boil off will force beer into it. when you open the can the sphere contents is at higher pressure and will force out the beer.
Love the artwork
So I should be hooking my nitrogen filled car tire to my keg of beer?
Not „widget” – more of gadget thingy.
Imagine miniature, shallow ultrasonic cleaner with a Guinnes logo.
Less than quid in local trift store ;)
https://www.reddit.com/r/Guinness/comments/16bxcsy/ultrasonic_surger_20/
What happened to all the comments on the “Estimating Celsius” article?
If you want to try real Irish beer I suggest you get some Smithwick’s.
Irelands oldest beer and far better tasting than stout.
And no plastic pats…
Indeed. Guinness isn’t really Irish either. It was devised as a tax-avoiding knockoff of London Porter.
You are in the business of communicating in English. Please, please, please get it right. The past participle of drink is drunk, not drank.
There’s an earlier article with the word “unphased” instead of “unfazed”. 😑
i love guinness but i think the alaska brewing stout is better. i may be a bit biased, i used to live across the creek from the brewery.