The tribunal found the former baker may have produced inconsistent bread, but he had not been set specific performance targets and received no clear warnings before he was sacked.
Piaszczynski started working at Leakers Bakery in Bridport in 2015, and was later promoted to head baker.
When complaints about his bread were made, the hearing was told, he was left notes by his boss, Caroline Parkins.
One note read: “I have asked you many, many times to make sure there are no holes in the middle of the loaf of bread.
“I have explained that our customers do not like to have holes in the middle when they are trying to make a sandwich or butter toast.”
During the tribunal, Piaszczynski said baking was an art, not a science, and that all batches varied.
Parkins, however, argued that, although some batches would differ to some extent, good, saleable bread did not have large holes in it.
The tribunal ruled that as Piaszczynski had a poor grasp of English, the notes were not a sufficient way of telling him to improve.
The notes were also not handed to him in person or emailed to him.
Judge Livesey found the bakery had not done enough to make him aware that he had been issued with warnings.
Daniel Zona, associate at law firm Collyer Bristow, said the way someone is dismissed is often more important in a tribunal, than why they were dismissed.
Speaking to HR magazine, he said: “Mr Piaszczynski’s case is a helpful reminder that despite having a fair reason to dismiss an employee, employers must always follow a fair and reasonable procedure and must always comply with the ACAS Code of Practice.
“In this case, the respondent failed to ensure its warning letters to Mr Piaszczynski about his underperformance were actually received by him.
“Employers should always ensure there is a record of any letter being sent and received, either by email or recorded delivery – or both where appropriate.”
Antony O'Loughlin, head of litigation at law firm Setfords, also said employers should ask employees to confirm that they understood warnings.
Speaking to HR magazine, he said: “The first formal meeting with an interpreter in this case was to give the employee notice of immediate termination.
“Where an employee is not a native English speaker, the duty to ensure clear, meaningful communication is compounded.
“The employer must use all necessary care and resources to ensure that concerns around performance are clearly communicated to and understood by the employee, which may involve the need for interpreters or translations.”
O’Loughlin said employers should set and monitor targets carefully from the beginning of an employee's time at the company.
He said: “Precise, realistic performance targets should as far as possible be communicated with employees at the start of their employment and should be consistently monitored.”