Does crème pâtissière need to be refrigerated?

The creme patissiere recipe in Domestic Goddess refers to the creme patissiere not being stored in the fridge for the best possible texture. If you use the creme patissiere once it has just cooled it will have a luscious silky texture, if it is refrigerated then it will still have a great flavour but the texture tends to be firmer and occasionally turns a bit grainy. It is however possible to refrigerate creme patissiere and this is preferable if the creme patissiere is made more than about 2 hours in advance. Once you have transferred the cooked creme patissiere to a bowl, press a damp piece of greaseproof paper, baking parchment or parchment paper on to the surface to prevent a skin from forming. Let the creme patissiere cool slightly then wrap the bowl tightly with clingfilm and transfer to the fridge. It should be used within 3 days. If the creme patissiere is too firm to spread once chilled then you can beat it with a wooden spoon to help to loosen it up a little. If it is still too firm then fold in a little whipped cream.