A fire at the five-star Randolph Hotel in Oxford appears to have started when a beef stroganoff was flambéed in the kitchen, bosses say.
Flames quickly spread to the first floor and the roof after the fire at the 150-year-old hotel in Beaumont Street broke out, on Friday afternoon.
Manager Michael Grange said early inquiries pointed to "perhaps too much cognac in a saucepan" being the cause.
More than 80 people were evacuated from the building. No-one was injured.
Assistant chief fire officer, Simon Furlong, said the initial kitchen fire was quickly put out but not before it had spread to first floor office areas.
"It appears it spread to the first floor and then jumped outside the building in a chimney effect," he said.
"There was a three-sided external gap and it jumped up to the roof area. It was fairly lucky it didn't get in to the internal workings of the hotel.
"It's a very rare occurrence, which I believe saved part of the hotel."
Mr Grange said about "95%" of the hotel had been left undamaged.
"It was quite distressing but it could have been so much worse," he added.
He said he hoped the hotel would be able to partially reopen, offering bed and breakfast, by the weekend.
Fire service personnel remain on the scene to monitor the building.
Scaffolding is due to be brought in to protect the roof gable ends from collapse.
A stretch of Beaumont Street remains closed to traffic, where diversions are in place.
All guests were accommodated at alternative Macdonald hotels, the group which runs the Randolph.