Heineken has had to fork out over £10,000 after sending 64,600 litres of cider and beer to a nearby effluent treatment plant.
The brewer pleaded guilty to breaching its environmental permit at its Tadcaster site and was fined £500 each for three offences and £800 for failing to notify the Environment Agency of the breach without delay. It also had to pay £8,225 in costs.
On 5 August 2008 faults at the site's plant resulted in 32,600 litres of cider being diverted to the nearby effluent treatment plant.
The effluent treatment plant was built for the use of Heineken, but is operated by a third party.
Selby Magistrate's Court heard that the company's permit requires it to notify the Environment Agency without delay of any issues such as those with the monitoring system, but it failed to do so until six days later.
The court also heard that on 8 August 2008 32,000 litres of beer were lost to the effluent treatment plant when an employee selected the wrong operating mode on a vat full of beer.
There were no training materials or written procedures provided to staff on how to operate this system properly. There were no notices or safeguards in the selection process, however the company has since disabled this part of the system.
The Environment Agency wasn't notified of this incident until three days later.
On 31 August, 2009, 11,000 kilogrammes of yeast was also diverted to an emergency tank after a pipe worked loose. An unknown amount of yeast was lost over a period of four hours. There was no inspection regime for this piece of equipment, so it was not maintained in good condition.
In mitigation, the company was given credit for its early guilty plea and the fact that there was no impact on the environment.
"This case proves that we take environmental regulation seriously, regardless of the size of the company involved," said an Environment Agency spokesman.
"Small breaches in procedure can lead to big environmental impacts. We're lucky on this occasion that there was no pollution, but the rules are there for a reason and, working with the courts, we will ensure that they are upheld."
A Heineken spokesman said: "Heineken UK has invested significant financial and management resources to continuously improve the safety and environmental performance at its John Smith's Tadcaster Brewery and all other beer and cider production sites in the UK.
"We submitted guilty pleas at Selby Magistrates Court today to four charges brought by the Environmental Agency, including administrative errors on the part of the brewery and its employees.
"While we regret that these errors were made, we would stress that they did not impact in any way on the local environment or neighbouring community.