So, to make my husband's birthday cake a bit more special I thought I'd try using a chocolate ganache as a crumb coat under the fondant....my question is what sort of consistency should the ganache be?  I have used it once and to be honest it was a bit like puty. It also seemed to set really, really hard - was that right or does it sound as though I didn't make it to the right proportions?   Thanks,  Helen

If using milk chocolate the ratio is 2:1 choc to whipping cream.  If using white chocolate it is 3:1 ratio choc to whipping cream.

Ropalma's ratio's are spot on.  But depending on your climate you may have to adjust the numbers a bit.   I am in West Tennessee and during the winter and spring months I need a minimum of 3:1 for milk chocolate and 4:1 for white chocolate.  This changes during the summer and fall months to a minimum of 3.5:1 for millk chocolate and 4.5:1 and up to 5:1 for white chocolate.  If you go with dark chocolate, 2:1 seems to work year round.

Maybe somebody in a different climate will share their ideal ratios.

If you find that your ganache set up to a point where it is hard to work with simply warm it for a few seconds in the microwave, stir it well and repeat until you get a thick yet pliable ganache to work with. It will reset nice and firm once on your cake.

You don't want it runny, first of it all it may well split of you warm it too much and second of all it is really hard to work with. 

Also I would apply a thinn crumb coat, pop in the fridge to set, apply thicker coat of ganache before applying fondant.

Should be like peanut butter for best spreading consistency.

Thanks for your replies.  I didn't realise I could reheat it but thinking about it, there's no reason why not to!   THe peanut butter consistency is also really helpful.  Thanks again.  Helen