Grubb was a successful baker by trade and had boasted of never conducting any business with the universities, which further endeared him to the people of Oxford. However, their love for him turned to anger in 1867 when it was revealed that not only was Isaac Grubb selling bread to the universities, but he was doing it in larger quantities than to the townsfolk and for a much lower price!

In fact, Grubb was charging the people of Oxford around 9d per loaf, and only charging his university clients around 6d! An angry mob formed in Oxford on 9 November to express their anger at Grubb seemingly profiting from the university at the expense of the honest working people of Oxford.

As the news of the protest spread outside of Oxford and into the countryside, the authorities in Oxford began to fear that they would soon have a full-blown riot on their hands. Their fears proved correct.

On the following Monday, a large mob of people descended on the city centre. As night fell rioting broke out, with Isaac Grubb's shop in Queen's Street being the initial target. A large number of special constables had been drafted in at short notice in an attempt to contain the rioters. They succeeded in preventing the mob from entering Grubb's shop, but not before they had smashed all its windows.

The mob then headed for Grubb's home, Somerville House on the Banbury Road. The authorities had foreseen this, and special constables stationed outside again managed to prevent the mob from gaining entry.

Having been thwarted twice, the frustrated mob turned back towards the city centre and began to take their frustrations out on university buildings and private residences alike, breaking windows and smashing streetlights before pelting the police station with stones.

The Riot Act was read, and the special constables succeeded in dispersing the mob at about 10 pm. However, the tensions were not fully deescalated until Grubb grudgingly agreed to lower his bread prices for the townspeople to match those he charged the universities.