This study examines the utility of grammatical ephemeral random constants, and conducts an analysis of the preferences of evolutionary search when a number of different grammar based constant generation methods are provided with Grammatical Evolution. Three constant generation techniques are supplied, namely, grammatical ephemeral random constants, digit concatenation, and an expression based approach. A number of constant generation problems are tackled to analyse this approach, with results indicating a preference for both the digit concatenation and grammatical ephemeral random constants. The provision of different constant generation strategies allowing the evolutionary process to automatically determine which technique to adopt would, therefore, appear to be advantageous.