SCOTTISH beer giant Brewdog has been forced to discard millions of pounds worth of beer after it became “infected”.

The wasted Punk IPA beer came after a “major quality incident” at Brewdog’s flagship brewery in Ellon, Aberdeenshire.

In an email sent to staff seen by the Daily Record, chief supply chain officer Chris Fielden said the “sour beer” had wound up on shelves as a result of staff failing to adhere to hygiene standards, leading to the “highest rate of customer complaints” the company has ever seen.

Fielden said the “major quality incident” meant the company’s productivity target for August was missed by £950,000 – adding that the wastage runs into “millions of pounds”.

In the email to staff, Fielden said: “The reality is that it was an incredibly tough month in which we significantly missed our productivity target and have been working through a major quality incident.

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“Throughout August and even now we’ve had millions of pounds of beer that has been impacted by basic hygiene issues that have resulted in infected beer.

“Not only have we had to throw beer away, we’ve also shipped sour beer to customers and have Punk running at the highest rate of customer complaints it’s ever seen.

The email adds: “Through the investigation we’ve ruled out many things and keep coming back to the same basic causes. Poor hygiene standards, particularly around the brewing operation.

"What’s most disappointing is that when I chat to people about this I’ve seen very little personal accountability with people blaming other teams or other parts of the process.

“As such, I wanted to be really clear that shop floor hygiene is the responsibility of every single one of us.”

In May, Brewdog’s millionaire former CEO James Watt (below) stepped down after 17 years.

We previously told how the company announced in January that it was going to stop paying the Real Living Wage to new employees.

The beer giant has also come under fire from staff, who accused bosses of presiding over a culture of bullying, poor working conditions, and health and safety breaches.

Brewdog also pulled out of its carbon neutral scheme in July, just several months after we reported that more than half of the Scots pine trees planted by the company had died.

A Brewdog spokesperson told the Daily Record that the amount of beer lost was “relatively small” compared to the company’s overall output.

They added that any customer who complained about the sour-tasting beer was given a refund.

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The spokesperson said: “Beer quality is our absolute number one priority. Unfortunately, earlier this year, we discovered that some batches of Punk IPA did not meet our high standards due to a minor, irregular process issue.

“While most of the affected beer did not leave the brewery, a small quantity reached some of our customers. The affected beer, which represents a minuscule proportion of our annual production (approx 0.02%), did not meet our high standards and did not taste as good as it should but we would like to reassure customers that it did not pose a health risk.”

They added: “The cause of the issue was quickly identified and resolved and any customer who raised concerns with us were recompensed appropriately. We apologise to anyone who has had a less than perfect beer.”