I just watched the three part youtube videos by InpiredByMichelle on how to make ganache, cover cake with ganache, and cover ganached cake with fondant to get sharp edges,  to prepare for making my son's birthday cake and make/use ganache for the first time.  I will fill and cover cake with ganache and cover with MMF.  (I plan on spreading ganache, not pouring, if that makes a difference in your answers.)

In the videos the ganache (made of twice as much cream as chocolate, only) is refridgerated overnight after it's first made.  After that, it sits out overnight after cake is covered in ganache, and again after covered with fondant before moving/stacking the next day so it's firmer when handled.  That's already 2 nights sitting out.  

Questions:

If I stack/decorate at this point (after 2nd night), the day before the party, I will need to let it sit out again -- for a 3rd night.  Is this okay? 

In some videos, the ganache sits out overnight (not in fridge) after it's first made to firm up.  Is this better than putting in fridge?  This however would add another night of not being refridgerated.  Can ganache sit out this long?  

Any advice/information? 

I love to use ganache when covering a cake with fondant.  I always refrigerate after each step.  Chilling will make the ganache set up nice and firm. 
 

AI just put mine in the freezer for a little while. It is fine siting out after completed.

Because the cream has been brought to boiking point before adding to the chocolate to make your ganache - it changes the structure of the cream....thus the reason why ganache can sit out of the fridg.

Some people put it in the fridg...it just hasens the firming stage - thats all.

As for when your cake is covered in ganache...as long as every morsal of cake is completely covered your cake will stay fresh.... and not require refridgeration.

I use ganache 90% of the time - and never need to put in the fridge....

A mud cake with a ganache fillling and then covered in ganache can sit out without any cause for concern for 3 - 4 days... at least.

Bluehue

I have been lucky enough to take a class with Michelle. I asked why she refrigerates the ganache after making it, rather than let it sit at room temperature. She explained that the texture of the ganache improves if it is refrigerated that first night, and since I tried it I have to agree. Once your cake is covered, it is fine to leave it at room temperature. And when covered in fondant it doesn't need to be refrigerated either. If you need to speed up the process you can fridge the cake to firm your ganache, but I find I am able to cover with fondant after it has been at room temperature for a few hours, though ideally I like to leave it overnight at room temp. I don't fridge any of my cakes since I don't use any perishable fillings. Unused ganache gets stored in the fridge for later use.
 

bluehue and dayti, thank you for the info.  I didn't want to ruin the cake and be stuck without one the day before.  

I've been looking up ganache recipes, and the ratios differ between a 1:1 and 2:1 (chocolate:cream).  So does that mean that it's really a matter of personal preference? Or is one better for spreading and one better for pouring or for whipping?  What have you discovered in your experience?  I would think that more chocolate means the ganache is stiffer, less creamy.  Which sounds better for covering with MMF.  Input?

AI usually leave it out. I've learned that with ganache and buttercream to tell when they need refrigeration. I like to decorate with my fireplace on for ambience : ). Sometimes my cakes start to melt. So I just put them in fridge a few minutes and start again.

I've hadleftover ganache sitting on my bench for a week and a half now, and it's fine. Ratios also depend on the weather. In very hot weather, I probably use close to a 3:1 ratio for dark chocolate.

I have a question, sometimes my ganache cracks after it's been on the cake.  Sometimes I get a BIG crack.  I mornally just patch it and move on with life and I've yet to have it show thru my fondant, but I was just wondering if there was something I was missing?

I do refrigerate my cakes because I can't leave them out at my rental commercial kitchen - my shelves in the walk-in are the only place they will be safe!

I use 1:1 for dark chocolate because I use chocolate with a 70% cocoa content. If I try and make ganache using 2:1 with that chocolate it's just too stiff. I use 3:1 for white and milk.

I don't use MMF...it's quicker and cheaper for me to open a pack of ready made fondant!

FromScratch I also get cracks, sometimes, not all the time. Only happens with dark chocolate ganache. I dunno why. I always let my cakes settle overnight before ganaching the outside. I don't fridge them so I don't think its the rapid temperature change. It's a mystery to me! I just patch over them and it seems fine.

I'm taking a Chocolates & Confections course this semester. I'll ask my chef-instructor who is a professional chocolatier. I bet she can crack the mystery of the cracking ganache.

ooh good idea, vgcea

adding gelatin would remedy/strengthen it

(not that you wanna add one more ingredient just saying)

it's a temperature thing--different crystals tightening up

chocolate shrinks a bit as it hardens

~~gotta love those world pastry forum notes ;)