The man who created the nitro stout

By Pete Brown

- Last updated on GMT

Michael Ash (left) and Pete Brown
Michael Ash (left) and Pete Brown

Related tags Guinness Beer

Pete Brown recalls the time he met the late Michael Ash, whose maths skills led to the world-famous Easy Pour system used by Guinness.

On Saturday 30 April, one of the most influential figures in brewing over the past century passed away. 

He defined the look and character of one of the world’s most iconic beers, and created a brand new type of beer that’s currently surging — if that’s not too much of a pun — in popularity among craft brewers around the world.

And yet, in all likelihood, you’ve never heard of him. I certainly hadn’t until I was invited to meet him in Dublin at the end of March.


Michael Ash was born in 1927. After gaining a mathematics degree and working as an actuary, he joined Guinness in 1951 and worked at its brewery in Park Royal, west London. During the following decade, he invented a dispense system for Guinness known as ‘Easy Pour,’ which was later refined and became Draught Guinness — the nitrogenated, smooth Guinness now known across the world.

The story has long been part of a legend that Guinness builds and guards very carefully. But in late 2015, someone at Guinness realised Michael Ash was still alive — a venerable 88 years old, still drinking draught Guinness at the Baskerville Arms near his home of Paincastle, just over the Welsh border from Hay-on-Wye.

Guinness promptly whisked Ash over to the St James’s Brewery in Dublin — his first visit for 50 years — and I was lucky enough to be there to meet him.


When he arrived at the new Pilot Brewery, Ash was walking on two sticks and was clearly frail. But as soon as he started speaking, he revealed a wickedly sharp mind.

“Can we get you anything? A pint of Guinness?” asked Mark Sandys, Guinness’s global head of beer.

“Yes,” replied Ash, “How’s Guinness Draught doing? I’d like to see some figures. Can you get some for me? Is it doing well?”

“Er, yes it is,” Sandys laughed.

“Well, I’d like to see some figures, please.”


You can say whatever you like about the executives who work for multinational corporations, but everyone in the room was clearly moved to see him, especially Eibhlin Roche, the brand archivist, who has spent the past 15 years reading about Ash as a historical figure and was now meeting him in the flesh, a storybook hero come to life.

I was invited, along with the two other journalists present, to sit down and talk to Ash.

He explained that by the 1950s, Guinness was popular on draught in Ireland but was sold in bottle everywhere else. The draught system in Ireland was fiendishly complicated, with the beer being stored in two separate casks — one under high pressure and one under low pressure — and had to be poured very carefully to get the perfect pint.


There was no hope of anyone other than Guinness experts, who sold huge volumes of the beer, being able to crack this, so Guinness was set to be a niche bottled beer brand unless the perfect pint could be
replicated some other way.

Ash was charged with solving the problem — a task regarded as so impossible that its code name: Project Draught — was amended to ‘Project Daft’ by his colleagues.
For Ash, the solution was mathematical.

He knew that nitrogen in beer had smaller, more delicate bubbles than carbon dioxide. These tiny bubbles couldn’t break the surface tension of the beer like CO2 did, so they remained suspended in the pint, helping to form the characteristic ‘surge’ that led to the two-part pour. All he had to do was figure out a way to get the nitrogen into the beer in the right way. This took him four years, and nitrogenated Guinness was finally launched in 1959.


The result was a redefinition of what Guinness looked like, felt like and tasted like. “We asked the MD how large the head should be. They didn’t know,” said Ash. “They didn’t think it was going to work anyway. So we had to decide ourselves that the perfect head was three eights of an inch, and it still is. It just looked right.”

Once perfected, Draught Guinness went around the world. From a research investment of £20,000, nitrogenation earned the brand billions, creating its entire ritual and iconography. The broader smoothflow category of beer and the widget ‘nitro’ can followed. Now, Nitro stouts and IPAs are being adopted by craft brewers, especially in the US.

Ash’s visit was commemorated with the unveiling of a plaque in brewery. It’s a poignant sight given that the man died a month later. But how lucky we all were that day, to celebrate a small, but colossally important, piece of beer history.

Related topics Beer

Related news