Cracked ganache on desserts: Why?

[beacheschef]

Last weekend I made a 2-layer stacked groom's cake that I delivered to a rehearsal dinner.

Each cake (9 inch square and 12 inch hexagonal cakes) had layers of chocolate cake with white chocolate mousse filling. The exterior of both cakes was glazed with chocolate ganache (semisweet), made with a 1 1/2 : 1 ratio of chocolate to cream. The cakes were cold when ganached, but not refrigerated afterwards, and were delivered about an hour later.

Both cakes were sitting on foamcore, and there were 5 thin dowels in the bottom cake to support the top cake. There was one dowel that I hammered through both cakes to keep them stacked and not sliding during transport.

When I left the shop, both cakes were fine. When I arrived at the location, there was at least one crack in the side of the bottom cake. By the time the cake was loaded onto a cart and rolled across the pavers on the driveway and through the hotel, there were more cracks in the bottom cake.

My first thought was that I need to cut my dowels slightly taller, so the top cake sits a bit higher.

What else could I have done to keep the bottom cake from cracking?

Thanks for any suggestions!

[JeanneCake]

how long did you let the tiers sit before stacking them?

I like to use some corn syrup (replacing about an ounce or so of the cream with corn syrup) when using ganache as a glaze; the formula I use also has some butter in it (2# choc, 2# cream, 8 oz butter).

But it doesn't seem as if the glaze was the problem .... in my experience when cakes crack, it's because the board flexes and causes the cake to crack (split). I haven't used foamcore for cake boards; I've been using the half inch thick drums made by a company in Canada - Enjay Converters. Most suppliers carry them now (Pfeil and Holing does, I'm sure others do too). Sometimes if a cake is very heavy, I use plywood; I've also seen thick masonite used by other bakers.

I don't know that your cake was especially heavy, but if the board flexed, that could have caused the first crack and then the rumbling across those pavers just made the situation worse.

I also use bubble tea straws instead of wooden dowels for support. They're strong, cheap, you can cut them easily ....

[beacheschef]

I've been thinking about your response and I remember the cakes being heavy. It would make sense that the foamcore bent a bit, which could cause cracking in the ganache. Next time I'll use covered plywood for cake layers this heavy - I thought about it at the time and figured it was overkill...how wrong I was!

I'll give the corn syrup recipe a try, too.

I'm assuming that your ganache glaze recipe was for semisweet chocolate - correct?

Thanks again-

[JeanneCake]

I've been using the same recipe for ganache for years: 2# bittersweet chocolate (callets or disks, either Callebaut or Chocoa now that Shokinag is no longer available), 8 oz butter in a bowl; 2# heavy 40% cream brought to a full boil and poured over; let sit a few mins then gentle whisking to bring it together.

When I use this to cover a flourless chocolate cake, in some display cases, the glaze will crack after a few days. But the worst problem is when I use this for my chocolate caramel tarts (in 9" and 4" sizes). I pour a layer of caramel (not too thick, but enough to coat the bottom of the shell. It's maybe a quarter of an inch thick if that), let it sit - sometimes overnight but sometimes for an hour or two; then pour ganache over it. The shells are probably 5/16ths or maybe half an inch shallow so these are not deep shells. The ganache is still fluid when poured but not warm to the touch.

The problem is that sometimes the ganache topping develops fissures across the diameter of the tart; sometimes caramel shows on the edges of the shell. The fissures are usually hairline, not wide (they get wider the longer they stand in the larger tart especially) but they are unsightly in my opinion because you can see caramel. Not all of the tarts develop a fissure or caramel around the edges so I can't figure out what is causing this. I don't refrigerate them once they are made; usually they go out the door within 36 hours of being made (e.g., we pour the caramel on Monday, ganache on Tues, pack and out the door on Tues or early Wed morning). The tarts are on parchment lined sheet pans, on a speed rack with a cover.

Should I be using a different formula for the ganache? The caramel sauce is the basic sugar/water/corn syrup with cream, vanilla and butter added and I am one of those who likes a very dark caramel in this kind of tart, but it doesn't seem to make a difference whether the caramel is dark or light. I am not using any added flavoring or salt on the caramel. We're making more this week so I'll see if I can get a picture. But any theories on what's causing this and how to avoid it are welcome!

[pastrygirl]

It may simply be drying out, or if you changed chocolates recently, you may need to adjust your ratio for the new chocolate. I add some honey or corn syrup to my glazes, and haven't noticed any cracking problems, but my stuff isn't sitting uncovered in a display case, either.

Did it work better with the schokinag? If it is only in certain display cases, what is different about those?

[chiantiglace]

dehydration. gelatin can help with the glazing. A proper glaze is made with cream, sugar, cocoa powder, gelatin and chocolate.

As for the tarts, rotate them more often, try not to let them sit more than two days.

[JeanneCake]

It's not so much a glaze as a layer of ganache; the ganache layer is about a quarter of an inch thick. I want them to have enough of each (the caramel layer and the ganache layer) to be distinct once it's cut. The caramel is just enough to run a little bit, it's the ganache that's firmer. I need to keep this a poured ganache rather than piping it on (the thought occurred to me) in order to keep labor costs down for this product.

Yesterday the staff made another big batch (300) of the individual ones and they used half Chocoa and half Callebaut dark in the ganache; almost half of the tarts has fissures across the centers, but some were perfect - no cracking or even the tiniest bit of caramel peeking out at the edges.

I agree a glaze would be better for the flourless cake, I just need to find the reason why the poured ganache cracks in the tart shell.

I've just started using the Chocoa brand and it seems to handle just like the Shokinag, so I didn't make any changes in the ganache formula. Maybe it's time to experiment.

[nice_guy1812]

I would agree with pastrygirl. The ganache is likely drying out. I normally use a bit of glucose or corn syrup in my ganache, and I find it helps with cracking. The glucose makes the ganache slightly more elastic, so it can expand and contract with less risk of cracking.

Also, I tend to not use butter in my ganaches. I like the flavour and texture that it gives, but I find the finish isn't as nice. Often it ends up having a dull appearance, and seems to crack more frequently.

[JeanneCake]

We have another order for these next week so I will add some corn syrup to the ganache, and report back! Thanks!

[Panaderia Canadiense]

I'd be looking at your chocolate as well - since you've switched you'll be seeing a different percentage of cocoa fats to solids, and this greatly affects the final behavior of anything made with the chocolate, but especially ganaches. The higher the cocoa fats, the more elastic the chocolate is at heart (that's why you can pour paper-thin coatings with milk or white chocolate and have them not crack, but when you try this with bittersweet or dark chocolates they fail miserably).

Also, with the Callebaut, is that their couberture chocolate? Are you tempering it? If not, you might try that before adding it to your cream mixture. With the couberture chocolate types, tempering greatly improves performance and ensures a more even distribution of cocoa fats within the chocolate. This is an especially good idea when you mix two or more types of chocolate together, as you're doing with the Callebaut and Chocoa.

This said, the ganache recipe I use has NEVER cracked on me, and I bake and glaze in what is substantially a desert. I've used this over caramel, over neat floured and flourless cakes, as a dip for decorative elements. It has never failed me.

10 oz black chocolate (I use a mixture of Superior 75% and Mother of Chocolate, which is something like 95% cacao solids - both of these are local, non-export products, unfortunately.)

3 tbsp butter

250 mL cream of the cream (nata; I guess that would be heavy cream in North America)

Melt and temper the chocolate. Bring the cream to its scald point, then add the chocolate all at once and whisk until completely blended. Then add the butter in smallish lumps and whisk until incorporated. I normally add a bit of brandy to mine when glazing my chocolate cakes, and leave it neat for other uses.

[Cassie]

Does anyone have any advice on how to prevent ganache from cracking or splintering when being cut with a knife. I am looking for an explanation of the chemical reason so I can correct it. I usually add the hot cream (I cool it to 105*F before gradually adding it to the melted dark chocolate (which is also about 95-105*). The texture of the ganache is creamy, but when I cut it into pieces, some of the ganache sticks to the knife or breaks off. I use a gently heated knife to cut my ganaches and that helps somewhat. I am wondering if there is a flaw in my recipes: not enough fat in the recipe--would that cause this?

[Kerry Beal]

Cassie - welcome to eG by the way - can we ask a bit more about the details of the recipe?

It may simply be that you need to cut with a wire instead of a knife if you are already very happy with the texture of the center that you are making.

[lironp]

That sometimes happens to me when the foot I spread on the bottom is too thick- by the time I finish cutting, the foot is really hard and breaks away, sometimes causing the ganache to break a bit as well

[lebowits]

That sometimes happens to me when the foot I spread on the bottom is too thick- by the time I finish cutting, the foot is really hard and breaks away, sometimes causing the ganache to break a bit as well

Two things when "footing". First, you're just going to have to get comfortable spreading a really thin coat with a pallet knife. I remember hearing this from another eG'er years ago and trust me, it just takes a little practice.

Second, many people use UN-tempered chocolate for the foot. It takes longer to get firm enough to touch, but it won't crack and break off anywhere near as much.

I've reached the point where I just don't have time to deal with untempered chocolate. I've got too many other things to get done. So I spread a really thin foot, and cut it as soon as it's dry to the touch. I do this on my slab caramels which are cut by hand and with ganache slabs which are cut on a guitar.

Don't fret. Practice and enjoy the remnants!

[Cassie]

Thank you, Kerry. I apologize for not responding sooner--I have been dipping my Kahlua, walnut marshmallows!

Here is an example of one of the ganaches that cracks--this one is a fruit ganache:

Raspberry chocolate truffles--

Raspberry puree, reduced with 50g of sugar:100g

Heavy Cream (41%): 168g

Invert sugar: 35g

Butter: 37g

Chambord: 35-40g

I heat the cream to a simmer, combine with the raspberry puree and bring back to a simmer. Add the invert sugar and cool to 105*F.

Temper the dark chocolate to 95*. Add the cream/rasp mixture slowly. Add the butter at 90*. Add the Chambord.

Pour into frame and crystallize overnight.

This is another example--a peanut butter ganache--

Creamy peanut butter: 270g

Milk chocolate, tempered to 88*F: 135g

Combine peanut butter and milk chocolate. Emulsify and pour into frame. Crystyallize overnight.

I used to add cocoa butter (35g, at 90*), but it made the ganache too firm and didn't have a creamy mouthfeel. It also added a bit of a waxy feel. It's still a bit firmer than I like.

I also have a hazelnut praline ganache that cracks when I cut it. could it be that the ganaches are not fully emulsified before they are slabbed? It seems that lack of fat is not the problem since the peanut butter and hazelnut praline ganaches are high in fat. Or is there too much fat?

[Nigelodeon]

Hello Cassie!

I'm new here and I'd like to share my toughts and knowledge too (:

To your problem now: Seems that your recipies have a lot of solidifying agents, I think you might get your problem solved if you add a little glucose syrup to your preparation. Just take around 40gr and add it to the cream before starting to boil it.

Also, adding a bit of butter to the chocolate/pb ganache might work, since adding glucose to that recipie might not be the best idea because there is no liquids to solve the glucose in.

Hope you try it and let us know if that fixed your ganache.

Cheers (:

Edited June 3, 2012 by Nigelodeon (log)