B767 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 245; Flight Crew Total 13500; Flight Crew Type 11000
Other / Unknown
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed
Aircraft
Climbing out of ZZZ at 6;000 feet; the Purser called the cockpit during sterile conditions to report multiple flight attendants smelling fumes aft of business class galley.  As climbout continued; the cabin crew report[ed] immediate dissipation of the smell.  No visible smoke or fire found.  Relief pilot sent to back to confirm no continuing threat.  Determined to be a transient condition with no secondary indications of malfunctions.  Flight continued to altitude of FL350.After another hour; Purser called again saying two other Flight Attendants had smelled an electrical smell similar to one when one plugs in a new computer for the first time.  It quickly dissipated as well.  Relief Pilot was awakened as a precaution to inspect the area.  He smelled nothing and found no secondary indications of smoke or fire.  He returned to the cockpit and a discussion of our situation followed.After lengthy discussions as we approached Coast Out to ETOPS airspace; we decided the most safe course of action was to turn the aircraft around and stay within close proximity of emergency alternates should the indications recur.  We briefed procedures and alternates throughout the return to ZZZ.  Since we never had a confirmed malfunction or irregular operation; we did not declare an emergency.  Safe landing in ZZZ occurred with no new indications of smoke or fire.  Maintenance and Dispatch were consulted throughout the evolution via SATCOM in flight and in person once blocked in.  Flight crew agreed that due to the possible escalation of the somewhat ambiguous indications; ours was the safest and most prudent response to this potentially catastrophic event.
[Report narrative contained no additional information].
A B-767 air crew on climb out were notified by flight attendants smelling fumes aft of business class galley.  The fumes dissipated.  Later; in cruise at FL350; additional flight attendants reported smelling the fumes.  The flight crew decided to not enter Oceanic airspace and to return to their departure airport.