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Fondant is cracking, sticky or sweating

The fondant splits as it goes over the cake, shows dry feathered edges, or has turned sticky and streaked with a wet-looking sheen.

Usually established at: finishing

Narrow it down

Answer what you can. Anything you skip simply leaves its causes in play — there is no requirement to answer everything, and no answer is treated as more authoritative than what you actually saw.

Is it too dry or too wet?
Had the cake been in the fridge?
How much icing sugar went onto the bench while it was rolled?
When did the cracking appear?

All 3 possible causes are shown below. Answer a question above to start ruling them out.

Every possible cause

The complete model, whatever you answered above. Each cause states the mechanism — what physically happens — because a cause without a mechanism is folklore with a confident tone.

The surface dried before it was used

Common

Rolled fondant stays pliable because glucose or glycerine holds water in it. Exposed to the air it loses that water at the surface first, and a skin forms within minutes. The skin is the same material with less water in it and much less give, so the moment it is stretched — over a corner, around a shoulder, off a rolling pin — it splits while the fondant beneath it is still perfectly workable. Every dusting of icing sugar on the bench does a smaller version of the same thing, taking dry sugar into the surface and moving it further from the ratio that made it pliable.

What to change

  • Keep it covered, and stop dusting it with icing sugar

    Knead, roll and lift in one go, and wrap anything that has to wait. Dust with a little cornflour or roll on a non-stick mat rather than working icing sugar into the surface. If a skin has already formed, knead it back in with a very small amount of white vegetable fat rather than with water, which will make it sticky rather than pliable.

    Rolled fondant and sugarpaste that cracks as it is applied or shows dry, feathered edges. Not a fix for cracking that appears hours later on a finished cake, which is the cake moving underneath.

    Trade-off: Working faster leaves less time to get the covering positioned, which is its own source of tearing.

Moist air condensed on a cold surface

Common

A cake taken out of the fridge is colder than the air around it. Water condenses on any surface below the dew point of the surrounding air, and sugar is hygroscopic, so the condensate immediately begins dissolving the outermost layer of fondant into a sticky film. It looks exactly like moisture being pushed out from the cake, and the two call for opposite responses. Wiping or dabbing at it spreads the dissolved sugar and dulls the finish; returning the cake to the fridge repeats the whole thing on the next outing. Left alone until the surface reaches room temperature, the condensate evaporates and the finish usually recovers.

What to change

  • Leave it alone until it reaches room temperature

    Take the cake out of the fridge and leave it somewhere with moving air, uncovered and untouched, until the surface is no longer cold. The condensate will evaporate and the finish usually recovers completely. Do not dab, wipe or fan it directly, and do not put it back in the fridge — each cycle repeats the condensation on a surface that has already been partly dissolved.

    A fondant-covered cake that has gone sticky or streaked after refrigeration. It does not help fondant that is sticky straight out of the packet, which is a humidity or formulation matter.

    Trade-off: It takes as long as it takes, and a large cake can need a couple of hours — which has to be planned for rather than discovered on the day.

It was kneaded with too much icing sugar

Common

Rolled fondant is pliable at a particular ratio of sugar to humectant to water. Icing sugar dusted onto the bench and worked in changes that ratio in the direction of dry and brittle, and it is cumulative — nothing takes it back out. A batch kneaded and re-kneaded through several dustings can be materially different from the one that came out of the packet. Cornflour or a non-stick surface does the same anti-sticking job without altering the material.

What to change

  • Keep it covered, and stop dusting it with icing sugar

    Knead, roll and lift in one go, and wrap anything that has to wait. Dust with a little cornflour or roll on a non-stick mat rather than working icing sugar into the surface. If a skin has already formed, knead it back in with a very small amount of white vegetable fat rather than with water, which will make it sticky rather than pliable.

    Rolled fondant and sugarpaste that cracks as it is applied or shows dry, feathered edges. Not a fix for cracking that appears hours later on a finished cake, which is the cake moving underneath.

    Trade-off: Working faster leaves less time to get the covering positioned, which is its own source of tearing.

Preventing it next time

  • Keep every piece of fondant covered whenever it is not actively being worked. A skin forms in minutes and has none of the stretch of what is underneath it.
  • Dust with cornflour or use a non-stick mat. Icing sugar on the bench is worked into the surface and cannot be taken back out.
  • Cover the cake only once it has finished settling, and never while it is warm.
  • Do not refrigerate a fondant-covered cake unless there is no alternative — and if there is none, bring it out well ahead and leave it strictly alone until it has warmed through.

Sweating is the room, not the cake

A fondant-covered cake that goes wet and streaky after coming out of the fridge looks as though moisture is being pushed out of the cake and through the covering. It is the opposite: water is arriving from the air.

Anything colder than the dew point of the surrounding air collects condensation, and a cake out of the fridge is exactly that. Sugar is hygroscopic, so the condensate immediately starts dissolving the outermost layer of fondant, which is what produces the sticky, glossy, slightly streaked surface.

The practical consequence is that the two instinctive responses both make it worse. Dabbing at it spreads dissolved sugar across the finish and dulls it. Putting the cake back in the fridge simply arranges for the whole thing to happen again on the next outing. The cake has to be left uncovered in moving air until its surface is no longer cold, at which point the water evaporates and the finish usually comes back.

Related

Where this happens

  • Fondant

    Losing water and gaining it are opposite faults of the same covering, and the corrections are the reverse of each other.

Possible causes

  • The surface dried before it was used

    A skin forms within minutes of exposure and has none of the stretch of the material under it.

  • Moist air condensed on a cold surface

    The opposite fault — water arriving rather than leaving — and the one whose intuitive correction is wrong.

  • It was kneaded with too much icing sugar

    Cumulative and irreversible: nothing takes bench dusting back out of the paste.

If none of this matches what you saw, the model has a gap. Tell us — that is how this section gets better.

Keep reading

  • Fondant

    What sets it, and therefore what the fix has to change.

  • Why baking fails

    The small number of things that go wrong underneath the large number of ways it shows.

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