Southern Highlands Brewing has had their Goodfather porter on tap pretty much since they opened the doors in 2015.

But interest in the beer has spiked since it won gold at the London Beer Competition in June.

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SHBC owner Ben Twomey said there were only eight gold medals awarded in the entire competition.

"Being one of eight golds from several hundred breweries from across 25 nations put it into context," Twomey said.

"There were also categories where no one got a gold medal."

Their Celtic Red Ale also won a Silver and the brewery itself was named best Australian brewery at the competition.

Ever since word got out about the Goodfather's win, Twomey said the beer has been walking out the door.

"As soon as we won that award, we got knocked out of stock of our porter," Twomey said.

"So everyone locally and in Sydney, Canberra and Wollongong who we deal with got their hands on it.

"There was four times the usual demand for it. So at the moment we're out of stock."

The beer was inspired by Twomey's father Patrick, who was a well-known Wollongong GP, and the dad of brewer Cameron James.

Both dads, who loved their dark beers, died of brain cancer so the Goodfather was brewed in their honour.

A dollar from every litre is donated to brain cancer research and,so far, Twomey estimates they've given several thousands of dollars to the cause.

The decision to enter the London Beer Competition was inspired by Twomey joining a delegation of Australian businesses on a trip to Shanghai and Singapore to get a feel for the export market.

That got Twomey thinking about looking for overseas markets for their beer, and what better way to draw attention to yourself than winning an award?

"Because we've got the roo on the can, that seemed like a good marketing product overseas," Twomey said.

"So in 2018 I started looking towards export and thought, 'if we're going to do that we need to get some international recognition. That's when we targeted the London Beer Competition."

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