The Cromwell Volunteer Fire Brigade was called back to the smouldering Bannockburn Hotel Restaurant and Bar when hot spots reignited about midday on Saturday.
The historic hotel was badly damaged on Friday by a fire which was believed to have started in or around a deep-fryer in the kitchen.
Publican Dave Gillespie said the damaged building started to smoulder under heat from Saturday's midday sun, sending smoke into the air.
"The brigade told us to ring them if we saw any more smoke, so we did. They just put more water on it . . . it didn't cause any further damage."
At the initial fire, firefighters from Cromwell, Alexandra, and Clyde worked for hours to extinguish the flames and dampen hot spots after fire spread across the roof.
Parts of the building were extensively burnt and smoke damaged, and some of the roof had to be removed.
Mr Gillespie said insurance agents would begin their inspection of the building today.
He would not know the extent of structural damage until a full assessment had been made.
Despite the building being off limits to the public for safety reasons, Mr Gillespie has opened a garden bar for business.
"We've set up a temporary bar in the garden area so people can still come and have a drink," he said.
Mr Gillespie leases the building, which is on the market freehold, along with the land.
The Bannockburn Hotel was first built on site by J, Richards in 1862, when it was timber-framed with corrugated iron cladding.
It has had major redevelopments in 1935 - when the timber frame was finished with stucco - and in 1994.
