Before we get to this week's question, a number of people have told me about this article. I'll just let it speak for itself, except to say I'm gratified to be mentioned.
HELP! You have totally inspired me to make truffles for gifts this year. But I’ve tried four times and they keep failing. I get this hard crust of something all over the top and they are all grainy. What am I doing wrong? HELP!
Note – this too a little emailing back and forth to find out where the issue was since it was not obvious in the question.
I actually had this happen this year also during a particularly large batch. In my case, and coincidentally this case, the causes were exactly the same.
In the past I too have struggled with some of my batches separating. That is what that hard crust is. The cream/chocolate emulsion has ‘broken’ and the cocoa butter has risen to the top and solidified. If you are desperate you can just remove the cocoa butter and move forward, but as noted, the texture may be a bit off. Grainy is a good description. In some cases, if you heat the ganache back up until it is about 100 F, you can stir the cocoa butter back in, sometime with the addition of a little cream at 100 F, and the emulsion will re-form and the texture will smooth out. If it is a really bad break, the best you can hope for is it simply not separating again.
But how do you keep it from happening? I have previously mentioned lecithin in your chocolate. In this case it acts as an emulsifier and can assist in keeping your ganache from breaking. But I can attest to the fact that it can still break. Stirring gently will also help. I have heard too if you add a small amount of alcohol then that will keep it from breaking….but I must be very special as I have done that and still broken the emulsion. So what to do? Those are all fine and good, but have the feel to me of urban (kitchen?) myth and susperstition.
Well, I think and hope I have a 100% full proof method now, and know what the culprit in all these cases has been.
Heat.
There are basically two ways to make a ganache.
1) Heat your cream and pour it over chopped or grated chocolate
2) Heat your cream and melt your chocolate and mix them together.
In either case, if you get your mixture over some moving target temperature your ganche WILL break. The crux of the matter is that that temperature changes depending on a bunch of other factors (lecithin, technique, fat content, batch size).
So I took an afternoon and made WAY too many test batches of truffle filling. Here is the short of it related to the final temperature, making the ganache with one of the two methods above. >105 F 100% success
110 – 120 F 80% success
125-135 F 60% success
140 – 155 F 20% success rate
Pretty obvious huh? If you are not carefully tracking temperature it can seem downright random. But there IS a solid pattern. Given that, here are my two recommended ‘fool proof’ methods.
1) Heat your cream to 100 F. Melt your chocolate to 100 F. Stir together until smooth. Let set up.
That’s my favorite method. So very easy and straight forward.
The next way has you doing less heating but I found is more prone to user error. In theory it should react the same every time, but the reality is that depending on your ambient temperature, the fat content (and bloom state) of your chocolate and your exact recipe proportions, your final temperature can vary. It is directly related to the chemistry and the amount of heat it actually takes to melt different crystal structures of cocoa butter.
With that caveat out of the way, here you go. It is predicated on my ratio of 60% chocolate, 40% cream, by weight.
2) Heat your cream to 145 F
Finely chop or grate your chocolate.
Pour the cream over the chocolate and let it set 10 minutes covered.
Stir until smooth.
About 50% of the time I had unmelted chocolate. Sometimes the termperature was pushing 110 F. When there were chunks left, I heated the mixture further by putting it on top of a pot of boiling water. It worked well enough but it is more fussy in my opinion. But it works if it suits you.
Give it a try and let me know how it goes.