Troubleshoot Chocolate Tempering

Recently I was asked about tempered chocolate that fails to keep a good shine and what can be done to fix that?  (See comments on how to temper chocolate page.)

That's a really good question.  Concerns about the streaking and the lack of shine make me think about how temperatures, crystal development and the appearance of chocolate are all connected.

Properly tempered chocolate is shiny and uniform in color. When chocolate has streaks and does not shine, it indicates that at some point in the production process, the chocolate solidified without being in a properly tempered state.

I am sorry to have to get technical here, but see if you can follow this.  Cocoa butter has to solidify or form crystals within a narrow range of temperatures.  Tempering means all crystals become as identical in size and shape as possible and we can do this by controlling the temperatures.   

There are essentially 3 major stages in the making of chocolates that you have to be particularly careful to achieve the right temperature:

Stage 1 - The Starting Product

If you make your own chocolate candy center, like toffee or ganache, make sure it is absolutely at room temperature before you dip in chocolate.  If you don't let it cool down enough, the heat will eventually push through your coating and cause it to lose its temper - either entirely or partially.  On the flip side, if you let the center get too cold, you essentially “shock” the chocolate.  This causes really BIG crystals to grow and the coating appears very dull, a flat finish.

If you mold your chocolates, use the molds at room temperature. This could be another source of unintended heat or cold introduced as the chocolate is solidifying.

Stage 2 - The Tempering Process

This is the most likely stage to produce streaking.

Agitating or stirring the chocolate during the tempering process is crucial to prevent streaking.  Imagine adding red food coloring to white frosting to make it pink.  If you stir in the coloring using only a few strokes, you will see streaks of red among the white. Continually stir and the frosting will eventually turn pink. Something similar happens when you temper chocolate without a thorough mixing.  Temperatures along the bottom and sides of the tempering pan will be several degrees different than its center.  Each temperature gradient grows different crystals at different rates.  This causes light to bounce and bend irregularly and we see alternating streaks of light and dark chocolate after it dries.

Too much stirring will cause air bubbles to form and get trapped within the coating.  Air bubbles cause crystals to form unevenly which gives the chocolate a grainy appearance on the surface.

If you use a tempering machine it may have separate milk, dark, and white chocolate settings.  If not, you’ll need to set up the temperature and mixing parameters differently for each type of chocolate that you use.  Milk chocolates temper at a lower temperature range than dark chocolates.  Milk chocolates are tricky because there are different percentages of milk in any given brand or formulation of milk chocolate coating. The higher amount of milk (milk fat), the lower the temperature.  White chocolates can be even more sensitive to temperature than milk chocolates. 

Stage 3 - The Cooling Process

This is the most likely stage to produce dull looking product with no shine.  The ideal temperature for cooling chocolate is between 65 and 68 F.  The relative humidity should be 50% or less.  I use a fan on a medium setting pointed right at my chocolates.  The fan will lift the humidity out of the air surrounding them.  Make sure the cooling tray is elevated off the counter top enough to let air circulate underneath and take away excess heat from the bottoms.  A refrigerator hovers around 40 F and a freezer around 30 F – these temps are too low to encourage a nice shine. Rooms that heat up during the summer spell disaster for chocolate.  Anything over 78 F is too warm and makes the chocolate soft and slightly sticky.

One obvious sign that the cooling process was unsuccessful is the formation of bloom.  Bloom is a gray dusty film that covers the surface of chocolate.  It can happen within hours, or days, after tempering and cooling.

To summarize, this particular tempering problem description appears to be a temperature issue at one of more stages of the process.

Bryn Kirk

Bryn Kirk

Course Facilitator at Chocolate University Online
Bryn worked for nearly 10 years in a research and product development for Ambrosia Chocolate Company in Milwaukee, Wisconsin. Now she develops all of the CUO lessons and coaches the members of the Primal Chocolate Club.
Bryn Kirk

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4 thoughts on “Troubleshoot Chocolate Tempering

  1. avatar Xavier


    I’m trying to mould chocolate bars and not always get the same results. I temper the chocolate using a batch temper machine and I test the temper with a knive… the result is ok. But when I mould the chocolate, the side inside the mould, the one with carvings, use to be fine, but the side that touches the air … sometimes has streaks, other times it is dull in some parts… the snap is ok, it doesn’t melt easily. It seems that the problem is just on the surface. I tried to let it cool at room temp (19-20 C humidity below 50%) or using a fridge for chocolate set at 12 C and humidity around 40% … the results are more o less the same. I fill the moulds with a syringe in order to control the weight… can it be the problem? I don’t know what I’m doing wrong…
    Any suggestion?

    Thanks in advance for your time

    1. avatar Bryn Kirk

      Streaks and dull spots usually indicates that the temperature (and therefore crystal formation) is not uniform through out the chocolate. The chocolate is not getting throughly mixed. You said you use a batch temper machine. When your chocolate is in temper and the machine is spinning, take temperatures in different areas and make sure that the result is consistent. You might have hot or cold spots from the heating element or water inside the machine.

      Also, you fill the moulds with a syringe. Be sure that the syringe is the same temperature as the tempered chocolate. Make sure, also, that the mould itself is the same temperature as the tempered chocolate. I don’t think you have a problem with cooling, but a good idea is to put a fan on the moulded chocolate while it’s setting. This will drive the latent heat quickly away from the chocolate as it cools.

  2. avatar julie clarke

    we have just opened a chocolate and coffee shop and are having trouble with tempering and getting air bubbles sometimes dusty look and streaks On other occassions really good confused as to what we are doing wrong??

    1. avatar Bryn Kirk

      Hi Julie,

      The air bubbles and dusty look suggest the chocolate was too cold and thick before pouring or dipping. Temper as usual but warm up slightly, and by this I mean only 1 or 2 degrees higher, before using. The shine should come back and when you shake out the air bubbles they should release better.

      The streaks indicate that the temperature is not consistent throughout the coating. It means there are warm spots and cool spots right next to each other. Better mixing (but not too fast or air bubbles will stay trapped) until uniform temperature throughout the entire coating will get rid of the streaks.



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