Thoughts on why ganache for truffles isn't setting up?

pjh

We recently posted a blog on chocolate truffles and accompanying recipe. It seems some people are having good success with it, and for some, the ganache fails to set up. After reading the comments at the end of both the blog and the recipe, if any of you baking scientists would like to jump in and shed some light on what might be going on - I'm sure a lot of us would appreciate it. Thanks-

badge posted by: pjh on December 23, 2010 at 8:16 pm in Baking, desserts and sweets
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reply by: pjh on December 23, 2010 at 8:21 pm
pjh

I should have added, not just baking scientists, but any veteran truffle makers or ganache experts... why the difference in how chocolate and cream set, and how stiff they get, when the same weight of both is used?

reply by: Jane Dough on December 23, 2010 at 9:35 pm
Jane Dough

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reply by: PaddyL on December 23, 2010 at 11:25 pm
PaddyL

Could it be that different brands of chocolate react differently? I mean the percentage of cocoa butter in the chocolate specifically. I am no scientist and I haven't made truffles myself simply because I would be too tempted!

reply by: vibeguy on December 24, 2010 at 7:33 am
vibeguy

Wow, I'm astonished at the number of low ratings and failures. That's kind of unheard of for a KAF recipe, and geez, there's no flour, no water and no eggs! Wow!

My guess is it's mostly related to chocolate composition. I use the equal mass rule of thumb to make ganache, and have for years, and I've never had a failure. I even use chocolate chips if that's all that is around. Stop warning people off using chips - they're the sturdiest chocolate around and in this application, you're not looking for high fluidity, you're looking for chocolate impact. I happen to think Ghirardelli 60% (formerly Double Chocolate) chips are knockout, and I have a cambro full of Callebaut chips right now that are as good as most other belgian chocolates, regardless of form.

1) The recipe you give calls for 2 cups of chopped chocolate. That's too much variation given the various ways you can pack it and chop it. Take the volumetric measurement off the recipe and out of the blog post. All chocolate packages will have weights on them.

2) Chocolate composition could be to blame. I primarily use Callebaut L6040NV, which is a very, very, very high solids/low sugar/low cocoa butter chocolate. I think it tastes fantastic. It does make a thicker ganache than say their 811 or 813, but is so thick you can't use it to dip truffles, for example, despite having all the "right numbers" for couverature.

Everybody talks about cocoa solids as a marker of chocolate intensity/quality, but that's a really misleading number. Those solids are a total of cocoa butter and cocoa mass. Something that claims to be 70% cocoa solids could be 30 grams of sugar, 20 grams of cocoa butter and 50 grams of cacao mass, or could be 35 of cacao mass, 35 of cocoa butter and 30 of sugar. They'd have totally different flavor profiles and melting behaviors.

A) Sugar Sugar (Oh, Honey Honey!)

Looking at your four recommended chocolates, there's a range of sugar between 25% (Onyx) and 50% (Peter's/Merckens) sugar. The Belcolade is 40%. Sugar + even a little water = liquid mess. Could it be that the failing chocolates are higher than 50%? Merckens Milk is 54%, same as a Hershey's bar. Special Dark is 51% and I've had good luck with it in ganache. Ghirardelli 60% is like 35% sugar, and I know it works.

B) Fat

I think FDA requires you to disclose added cocoa butter, but doesn't require you to disclose if you've defatted the chocolate liquor. The technical services people from all of these chocolatiers would gladly take a call from y'all and be very candid about the fat content of these products at a more specific level than is disclosed on Nutrition Facts labels. Suffice to say, the four chocolates mentioned are all pretty high-viscosity chocolates (lots of cacao mass, not a ton of cocoa butter), so they'd tend to have more water-holding capability. Getting cocoa butter to stick to water requires...

C) Emulsifiers

All of these pro brands have lecithin in spades, as they're designed for formulation into finished products. I don't know if that's the case for "consumer" finished/eating chocolates.

I'm not surprised by the failures with the milk chocolates - between the hygroscopic lactose, the milk protein, the high sugar contents and the low cacao mass content of milk chocolate, I'd suspect milk chocolate ganache is going to be a soupy mess, *especially with Lindt*.

The failures with dark chocolates surprise me. Not all dark chocolates are created equal, but I've *never* had one fail utterly. When I make ganache, I chop the chocolate with a cuisinart (pretty fine), then pour the chocolate into a stainless steel bowl (room-temp), and pour the cream over it. I let it stand for a couple of minutes, correct the seasoning, and stir until it's smooth with a Rubbermaid high-temp scraper. I wonder if people are heating the chocolate in the cream and somehow seriously, irretrievably breaking the fat. If I add 100 grams of 100C (boiling) cream to 100 g of 22C chocolate, the mixture won't be any hotter than 60C, which is above the melt point of cocoa butter (duh, the chocolate melts) but not egregiously so (cocoa butter, to my mind, melts at 36C). I'd have to dig for some references to get a specific temperature number, or go make some ganache, but I bet no good comes of chocolate heated much beyond 65C, at least texture-wise. The pan the cream is heated in is going to hold a *lot* of heat...I always pour cream over chocolate in that room-temperature bowl...overly-hot solutions are also harder to emulsify. Now I really wonder how hot my ganache gets when the last of the chocolate is melted and I stop stirring. I *bet* it's around 50C or so. Maybe I'll make some later... I also can't recall off the top of my head if ganache is water-in-oil or oil-in-water. That would definitely inform my thinking.

I also wonder if people are using products with added vegetable fat rather than nothing but cocoa butter (the US, Canada and England are notoriously lax about what can be called chocolate).

I wish I had a surefire single answer. It may well be a combo of all three (sugar/water, total fat, emulsifier content) and some combos of chocolate and cream are just more stable than others because of the interrelationship of the three factors rather than just an absolute level of one in particular.

PS, I don't think it's the cream composition. There's some old hoary French pastry tome that says to boil the cream three times before making ganache, which leads me to believe you can abuse the heck out of the milkfat and protein and still have workable ganache.

E

reply by: Mike Nolan on December 24, 2010 at 11:10 am
Mike Nolan

I was having inconsistent results with ganache for macarons for the past few months, I think undercooking the cream was the primary culprit, along with the ratio of chocolate to cream.

(I was using the same five pound bag of Merkens bittersweet chocolate for all the batches, so that's not a factor.)

I tend to measure by weight, 6 ounces of chocolate to 4 ounces of cream is what I've settled on. I cook the cream until it just starts to boil, then as it cools I add 1/2 teaspoon of unsalted butter.

However, this is not a ganache intended for truffles, for that I'd probably want to add some more sweetness in the form of some softened confectioner's fondant.

reply by: wingboy on December 24, 2010 at 12:17 pm
wingboy

Thanks Vibeguy - I learned a lot from your post.

reply by: Mike Nolan on December 24, 2010 at 12:34 pm
Mike Nolan

The recipe for truffles in the Pope cookbook is made with Parisian pudding, which is made from 1 1/2 pounds of milk chocolate that has been melted and beaten until smooth and 2/3 to 3/4 cup of 22% cream that has been scalded then allowed to cool to 130 degrees plus 1 1/2 teaspoons of vanilla. Add the warm cream to the melted chocolate, beat until smooth, then add the vanilla and beat until mixed.

For truffles you chill the pudding, cut it into squares and roll it into balls.

I've only made it once, but it was very good.

reply by: omaria on December 24, 2010 at 6:57 pm
omaria

Vibeguy and Mike , my wish for the New Year is that you both become my neighbors.

reply by: vibeguy on December 24, 2010 at 10:27 pm
vibeguy

There goes the neighborhood!

reply by: toffee on December 25, 2010 at 2:51 pm
toffee

I made truffles with your recipe. They were perfect. I used Guiardellis (sp)? 60% bittersweet chocolate chips. I brought my cream to just boiling as stated, then stirred in my chocolate. I poured it into a 9x13 pan and let it get cold for about 3 hours. I used a cookie scoop and it was sticky, but workable. I like the ones I rolled in the dark chocolate cocoa better than the nuts or sprinkles but that is a personal preference. I would make them again and next year will try something more adventurous than vanilla for a flavoring. One truffle takes care of a chocolate fix all day. Lol

Patty

reply by: dachshaven on December 25, 2010 at 10:24 pm
dachshaven

Thanks a bunch for the knowledgeable information.
I learned a whole lot!

reply by: Mike Nolan on December 26, 2010 at 11:46 am
Mike Nolan

Just read through all the comments on the blog. While I think the specific chocolate used (especially milk chocolate) may be the culprit, there could also be an issue or two with the cream.

You can't always tell from the package what the % of butterfat in cream is.

I think in the USA if it is labeled heavy cream it must be at least 30% butterfat, but when groups like Cooks Illustrated have tested it, they have seen heavy cream range from around 30% to 40% or more, and that's assuming people are using 'heavy cream' as opposed to 'table cream' or something else that is usually a lower butterfat content.

'Whipping cream' doesn't have to be 30% butterfat to whip, I think even 22% butterfat cream will whip, though the higher the butterfat the better it whips.

I also have had my suspicion for several years that the ultra-homogenization and ultra-pasteurization processes which are used for many or most brands of heavy cream these days affects how the cream cooks in candies and possibly even in sauces.

Is it possible to contact the people who are having problems with it and get more information, or at least collect that information in the future?

reply by: vibeguy on December 26, 2010 at 3:51 pm
vibeguy

Ultrapasteurization clearly affects whipping performance, but shouldn't affect ganache, as you're not relying on the protein skin on the fat micelles. It's also not the sole source of emulsifier in the system - the chocolate's lecithin is a larger contributor by far.

The only recipe I can't get to work with an ultrapasteurized 44% cream is Fredy Giradet's cream tart. It's brilliant, but it *never* sets with anything other than raw or standard-pasteurized cream.

reply by: biobaker on December 27, 2010 at 9:44 am
biobaker

Mike, I doubt that your inconsistent ganache results come from "undercooking" the cream. When using modern commercial (i.e. pasteurized) cream, the purpose of heating the cream isn't to "cook" it but to heat it enough to completely and thoroughly melt the chocolate. If you're weighing your chocolate and using the same ingredients each time, I'd take bets that the problem involves humidity and/or mixing technique.
Ganache, as I understand it, is an emulsion of fat in water, with the goal being to prevent crystallization of the cocoa butter by suspending very small crystals in a sea of something else that keeps them from touching. When ganache breaks, the cocoa gloms together, excluding the water and creating a grainy texture; the grains come from those large, perceptible cocoa butter crystals.
Vibeguy, great discussion of the elements involved here. I suspect that the majority of problems boil down to two things: chocolate quality and mixing technique. Specific scenarios I can imagine:
1. Chocolate contains fats other than cocoa butter – “melting chocolate” or “candy disks” and even many chocolate chips contain palm kernel oil or other vegetable fats. Cocoa butter has very unique crystallization properties that I don’t specifically understand that well, but I know that cocoa butter and palm kernel oil crystallize very differently. The presence of other fat crystals might interfere with cocoa crystallization and cause the ganache to seize.
2. If people’s ganache isn’t setting up, as VibeGuy has said, it’s likely that they are using less chocolate than called for in the recipe due to inconsistencies in measuring by volume. It’s also possible that
3. Finally, mixing technique. The goal with ganache is to suspend very small crystals of chocolate in a sea of cream. It’s important to stir constantly while mixing the hot cream and chocolate together both to melt the chocolate and to create those small particles suspended evenly in the emulsion. Too much vigorous whisking after the emulsion comes together could promote condensation of all those little particles and cause the ganache to break.

Ganache is complicated on a technical level, but it’s really simple on a practical level. If people are having problems with ganache not setting up, I’d bet my second-best rolling pin that they’re not using enough chocolate.

reply by: Mike Nolan on December 27, 2010 at 12:48 pm
Mike Nolan

I don't think my ganache is breaking or seizing, it is smooth (eg, not separated) and doesn't feel gritty in the mouth, which it would if it crystallized.

It just doesn't always get firm quickly, though it usually firms up in the refrigerator after a day or so. I've got some egg whites to use up today, I may make a batch of macarons and make some chocolate ganache to see how it works today.

According to the article on Wikipedia, ganache for truffles is two parts of chocolate to one part of cream. The King Arthur recipe uses equal parts of chocolate and cream, so I would expect it to be a lot softer.

I got a copy of Rose Levy Beranbaum's Cake Bible for Christmas (some elf was paying attention!) and I see it has a number of recipes for ganache in it. But they may all be intended for going on or in cakes, so I would expect them to be fairly soft as well.

reply by: vibeguy on December 27, 2010 at 3:09 pm
vibeguy

Do you think the cocoa butter goes back into beta crystals in ganache? I was wondering about that, which is why I proposed the "overheated" hypothesis.

I was looking through the recipe, and I note that the *pictured* tests were all with dark and bittersweet chocolates, but many of the failures were from the Mercken's milk and Lindt (which I'm guessing was not the 70% Excellence)....PJH - were milk chocolates actually *tested* at 1:1?

E

reply by: Mike Nolan on December 27, 2010 at 4:51 pm
Mike Nolan

We're WAY beyond my expertise in chocolate here. There are days when it seems like it takes a degree in colloidal chemistry to know the answers. :-)

I saw a comment once: Chocolate is one of the easiest ingredients to cook with, and one of the hardest.

I'm tempted to try the process given in Pope, heat the chocolate and beat until smooth, scald the cream then cool to 130, then combine the two. I have my suspicion it works better in larger quantities, though, it's kind of tough to beat a small quantity of chocolate.

reply by: lenored on December 29, 2010 at 10:19 pm
lenored

Wow...i learned a lot, thanks. I agree that the first thing is to change the amount of chocolate to weight. My 2 cups chopped could be as much as 6 oz different from your 2 cups chopped (using the extremes of nearly cocoa powder to roughly broken). it should provide more consistent results plus it will make shopping for this recipe considerably easier.

reply by: Mike Nolan on January 16, 2011 at 2:45 pm
Mike Nolan

I just posted a recipe for buttermilk ganache. It may not thicken quite enough to use for truffles, but it is an interesting twist on ganache.

I used most of it to frost a batch of Katherine Hepburn brownies.

reply by: Mike Nolan on January 17, 2011 at 3:04 pm
Mike Nolan

Followup: It took a day or so for the ganache to set up enough (on the counter, it would have probably happened faster in the fridge) but I think this ganache would make excellent truffles.

reply by: hickeyja on January 17, 2011 at 9:21 pm
hickeyja

Mike, if it took a while for this ganache to set up, maybe it would work for the Boston Cream Pie...

I would think the the extra 'tang' would be a nice counter-point to the sweetness of the cake and custard. Jan

reply by: Mike Nolan on January 18, 2011 at 2:40 pm
Mike Nolan

So many things to try, too few calories permitted in a day. :sigh:

I think if you kept the ganache warm so it could be poured/spread on the Boston Creme Pie quickly (the cake needs to be cool or it messes up the custard/pastry cream filling), it might work, I'm a bit less certain that the tastes would mesh right.

I frosted the brownies while they were still warm, so it didn't make much difference how much the ganache had set up by then.