A polyol composition is made by polymerizing a mixture of ethylene oxide and propylene oxide onto a mixture of at least one diol initiator and at least one triol initiator, followed by polymerizing 100% propylene oxide or a mixture of at least 90 weight percent propylene oxide and at most 10 weight percent ethylene oxide. The resulting polyol composition has a hydroxyl equivalent weight of 200 to 400 and an average nominal functionality of 2.05 to 2.95 hydroxyl groups/molecule. 5 to 30 percent of the hydroxyl groups of the coinitiated polyether polyol are primary hydroxyl groups and polymerized ethylene oxide constitutes 40 to 63 percent of the total weight of the coinitiated polyether polyol.