How to pour the perfect pint of Guinness this St Patrick’s Day, according to science

As St. Patrick’s Day rolls around once again, beer guzzlers from far and wide will no doubt flock to get their hands on a pint of Guinness.

But pouring the perfect Irish stout is trickier than it looks, with drinkers often stunned by the horrors of huge foam caps.

Fortunately, help is at hand, as scientists have revealed the perfect way to pour a pint, whether from the tap, bottle or can.

Unlike a lager or an IPA that can be poured into a pint glass all at once, the key with a Guinness is a two-part pouring technique.

Here’s everything you need to know about pouring the perfect pint of Guinness on St. Patrick’s Day.

For bar and pub tenders, Guinness has devised another ‘two-part’ pour to achieve the ideal appetite.

It recommends pouring the Guinness Draft into a dry glass at a 45-degree angle until it is about three-quarters full.

Pourers are then encouraged to allow the bubbles to settle before finally filling them all the way.

If you’re pouring from a bottle, the Irish stout company recommends a similar approach of tilting this at a 45-degree angle to a glass so they can’t touch each other at any stage.

But this time it can flow out all at once until the end of the bottle is reached.

Guinness explains: ‘Pour slowly in one pour, the bottle should never touch the glass. When you reach the end of the bottle, the head will just come over the top to create a nice browned head. Your perfect Guinness is now ready to drink.’

Despite this advice, Professor William Lee of the University of Huddersfield suggested that tapping could be a much faster process that is currently ‘as much about marketing as it is about physics’.

He explained: ‘It’s become a time-honored ritual in pubs around the world. Much of that time is settling. But this period is as much about marketing as it is about physics. You might wait longer than for another beer, but that’s the way it should be.’

Bubbles in Guinness are filled with nitrogen, he explained, while most beers are carbonated with carbon dioxide.

Unusually, the bubbles in Guinness pints also sink rather than rise, which he says is due to the shape of the glass walls pushing them down.

“As it sinks, it takes the bubbles with it. So that’s why you see the sinking bubbles in Guinness with the little bubbles being carried down by the current,” he added.

As advice that will fill many Guinness aficionados with dread, Professor Lee recommends drinking the drink from a giant cocktail glass.

In a video for Tech Insider in 2018, he said: ‘Every Guinness should be poured into a specially crafted tulip glass. But that glass is designed to manipulate the bubbles in the beer to turn the pouring into a performance, so you have to wait longer than necessary.’

Commenting on this, Anna MacDonald, Category Marketing Director Beer at Diageo GB said: ‘A beautiful, great tasting pint of Guinness Draft is served with our famous ‘two part’ pour. First, pour the Guinness Draft into a clean, dry Guinness pint glass tilted at a 45-degree angle until it is three-quarters full.

‘Now it’s time to wait! Let the wave settle before filling the glass all the way to the brim and create the perfect pint!’

If you want to make pouring a pint even easier, engineers at the Dublin brewery have also released an ‘ultrasonic’ device called ‘Nitrosurge’.

The ‘pioneering’ £25 electronic device attaches to the top of a Guinness can and pours a perfectly straight jet of liquid – as if coming from the draught.

Having come to Ireland in September 2021, the Nitrosurge device is now available from Tesco and will be coming to other UK retailers later this year.

“We know people want the opportunity to enjoy the iconic two-piece pour and the cold, smooth taste of Guinness wherever they are,” said Neil Shah, head of Guinness GB.

“With Nitrosurge, we’ve pushed the boundaries of technology to give Guinness fans an enhanced pouring experience that delivers beautiful, great-tasting Guinness every time.”