This is my very first post, I love being here and learning so much. My question is for raspberry ganache made from fresh fruit. The ganache will be for cake filling, working with dark chocolate 60% 2:1 choc to heavy cream. Do the raspberries have to be boiled up in sugars and reduced before adding? I'm wary of molding since the cake will be worked on for approx three days for celebration icing and decoration. It can not be refrigerated although it will be in a cool environment. I'd be interested to know what kind of shelf life to expect, and would appreciate any input. Thank you.
I would worry about mold with a fresh raspberry puree esp. since it will be sitting for several days. Fresh fruit purees are not boiled when they are made. You puree up the fruit, run it thru a sieve to remove seeds and then add about 10% sugar by remaining weight. That said, various recipes do call for reducing the puree in half before using it in a ganache (it intensifies the flavor and reduces water content). Other recipes don't call for the puree to be reduced at all. I have a suggestion that might avoid the issue for you. Consider making just a plain chocolate ganache. Then use your puree to make a "jelly" to put on as another layer on the cake (puree, sugar and pectin and then undercook it to avoid it being too thick). The flavor will be nice and intense and I think you wouldn't have to worry about mold nearly as much.
Thanks Andrea for your reply and confirming what I was thinking. Making jelly sounds good but I was hoping to do something a little different with the ganache, can the jelly not be added to the ganache without worrying about molding? I keep reading about fruit flavoured ganache in cake fillings, so I guess these must be used on day of bake and consumed quickly. Would the same apply if I was to use freeze dried raspberries. hydrated and pureed? I've come across comments about dried fruits being used in chocolate making and was wondering whether the dry freeze might be a possibility. I've also been told adding glucose/glycerine can extend shelf life. I don't know whether that is correct plus I wouldn't know how it would affect the consistency of the ganache. Do you have any thoughts on this? Finally do people use butter ganache as cake filling? So many questions!! Perhaps I should just make some up and see how it holds up. I really appreciate your advice, thank you.
I don't know much about freeze dried fruits. I've never used them after they have been rehydrated. I have used them in their freeze dried form and they are very flavor intensive. Raspberry might be too tart this way though and as I said I don't know about rehydrating them.
I have made raspberry ganache previously and my only comment is that you will lose some of the intensity of the fruit flavor. So if a subtle raspberry flavor is what you want a ganache is a great way to go. You'd probably be just fine making a raspberry-flavored ganache for the cake and not have to worry about the mold issue. You will get a more intense raspberry flavor if you reduce the puree before adding it. You could also extend the shelf life if you use glucose (corn syrup) in the ganache. Also, I'd use the puree in the ganache (as opposed to a jelly) because it will be a "fresher" flavor. Good luck with your cake and ganache! Andrea
How does adding glucose to the ganache extend the shelf-life?
Sweeteners like glucose do several things for ganaches. They increase shelf life, improve texture and stabilize it (i.e prevent separation). They increase shelf life of a ganache by binding with water which lowers water activity levels and making it more resistant to spoilage.
I feel much more informed now, at least I can experiment and see how long the ganache stays good. I'll post my results after experimenting, can't thank you enough Andrea.
1kg milk chocolate broken into small pieces
500ml of raspberry puree'
125g granulated sugar
190g unsalted butter (optional)
Bring the raspberries and sugar to a boil on your stove, and simmer for 5-10 minutes.
Put into a food processor to break down all of the fibres in the fruit.
Strain through a very fine siev to get the seads out.
while hot, mix into the chocolate and stir until smooth.
Let set in the fridge.
If you find the ganache too thick to work with at room temperature, you can add the butter, and that will soften it up considerably, and give it a velvety texture.
This is essentially one of my company's truffle fillings (almost), with the exception that we whip it like whipping cream to incorporate air into it and make it very fluffy before we make it into truffles. It's one of my shop's most popular centers.
Hey Brad, that is so generous of you, I will definitely make this up and get back to you. So this is ok for filling a cake which needs to be decorated over a period of say three days without refrigeration? Thank you soo much!
Yes. It's fine.
Let me know how it works out for you.
I just want to make sure that I understand that you're looking for this ganache to be the filling between layers of the cake.
And - how cool is cool?
The observation about glucose is interesting ... but did you know that honey is also an invert sugar and that it can be used the same way that glucose/trimoline are used? Try Brad's recipe with a neutral-flavored honey (or replace some of the sugar with honey) and use as little extra water as possible when heating the fruit to incorporate the sugar/honey.
Also, once you open your containers of dairy, technically they are no longer pasteurized. So while heavy cream has a lot more water than butter does, you can put it on a stove and re-pasteurize it (bring it to a boil, take it off the heat for 1 minute, return it to a boil a second time, take it off the heat for one minute, re-boil, take off the heat and let cool to 160F (70C) then use the heat of the cream to melt the chocolate.
When you mix the ingredients together - cream, chocolate, sweetened fruit puree - take care to mix in as little air as possible. Use a wooden spoon or spatula and not a balloon whisk. There are spores in the air that will grow in the water in recipe. The more air you mix into the recipe the more spores there will be.
My recipe doesn't call for extra water, nor does it call for cream.
I can only assume here you're talking about a situation where Rosanne uses a different recipe...
Clay, thanks for your input, yes the ganache is for cake filling. I want to try different things. I would like very much to use Brad's recipe which would mean leaving out the dairy, I don't mind doing that. Your advice on pasteurizing the cream is very helpful as I always understood that because the cream was brought up to almost boiling was enough for pasteurization. I will certainly try honey. Thanks for being so specific on temperature and mixing of the ganache, these things are all new to me so I'm really learning good stuff here. When I say a cool room I mean one which is totally heat free, in fact it's almost as cold as the refrigerator, brrrrr, that's my kitchen! I think what I'll do is make very small amounts and keep out on the counter covered up to see how it behaves. Not all of my cakes take three days to enrobe, however it's good to learn whether it will be ok with ganache filling. I have to also take into account how it will be stored once out of my tender loving care! I much appreciate all the advice, from yourself, Brad and Andrea. I'll get back and let you guys know how I did.