The officer was targeted in the unexpected attack despite having helped the young person when he first came into detention.
Sugar had been added to the water thrown onto Fowler in a bid to make the injuries potentially worse, the court heard.
The judge said: “This is a prison officer who, on your own admissions and in your apology letter, you say helped you when you came into prison.
“This was a prison officer of 17 years. This will not be the first time he has been assaulted and sadly it probably will not be the last before he retires from that line of work.”
Two female officers who were standing either side of Fowler felt a “stinging sensation” as the water also hit them on the arms, but left no injury, the prosecution said.
In a statement heard by the court, Fowler said: “If it had gone in my face and eyes, things could have been different.
“I was just glad it didn’t happen to me and it didn’t happen to a female officer.”
The officer said parts of his skin had changed colour and while it did not cause him physical pain or discomfort it was a “lasting reminder of what happened to me”.
Thirteen empty packets of sugar were found in a bin bag when the teenager’s room was searched, the court was told.
