The present invention relates to a method for predicting the microstructure in which a certain cast iron melt will solidify comprising the steps of: a) taking a sample of the cast iron melt having a predetermined weight W; b) adding the sample to a sample vessel containing an amount of a neutralizing agent, preferably tellurium, which is sufficient to change an amount W of molten grey cast iron to white iron; c) recording a cooling curve in the centre of the so-obtained treated iron sample; d) determining the local maximum value Te(max) of the cooling curve obtained in step c); and e) predicting whether the cast iron melt will solidify as SGI, CGI, flake patchy or grey cast iron by using the information obtained in step d).