The invention relates to a method for preparing polyglycerol, comprising —providing a catalyst salt on a support, the catalyst salt having catalytic activity with respect to an etherification reaction of a polyol selected from the group of glycerol and oligoglycerols, —contacting the catalyst salt on the support with a fluid phase comprising a polyol selected from the group of glycerol and oligoglycerols, —and subjecting the polyol in the fluid phase to an etherification reaction in the presence of the catalyst salt, thereby forming the polyglycerol.