Highly branched polyether polyols of high molecular weight (such as over 12,000) are made by coupling an alkoxylated polyglycerol, by reaction of the sodium alcoholate of the oxyalkylated polyglycerol with a dibenzenesulfo or ditoluenesulfo ester of a diol containing 2 to 6 carbon atoms. Products obtained are viscous resinous products which are particularly suitable for use as hydrophilic water-swellable gels and other purposes.