3015 views| 2 comments
Copyright © 2000 Sarah Phillips CraftyBaking.com All rights reserved.
Chocolate is versatile: it can be melted or tempered, used in recipes, molded, sculpted, spread, piped, dipped into and chilled, to name a few. Sometimes problems occur, but we have solutions for you here.
If you have additional questions, please post them in our CraftyBaking.com Forum, and we will be happy to answer them.
The basis of chocolate is a delicate emulsion of cocoa solids and cocoa butter. If it is improperly stored or tempered, the emulsion breaks down causing either one or both types of "bloom" to occur -- fat bloom and sugar bloom, a colored film on the outside of the chocolate. Melting and/or tempering bloomed chocolate eliminates the problem, although chocolate affected with sugar bloom should not be melted and used for fine candy making.
Seizing: If moisture in any form comes into contact with the chocolate will cause it to seize or thicken or harden, rendering it useless for tempering and chocolate work. If not burnt, you can try to fix it, and use it in a chocolate recipe.
QUESTION: But why does chocolate seize from tiny droplets of water?
SARAH SAYS: It has to do with the sugar crystals in chocolate getting wet, making them clump.
If the chocolate has seized, there is really no way back to the original chocolate.
However, if some more water is added, the grainy mass magically turns silky smooth again.
Why this works: Basically more added water helps to dissolve the clumped sugar crystals.
How does this work? "Basically, chocolate is
- cocoa fat (cocoa butter) - water repelling
- sugar particles - water loving
- cocoa particles - somewhat unclear*
- lecithin emulsifier - water repelling and water loving
(for milk chocolate: milk fat and/or milk powder)
Chocolate is a dispersion, consisting of solids distributed in a fatty (continuous) phase", or when chocolate is melted, its ingredients— cocoa fat (cocoa butter), sugar, cocoa particles, and lecithin —disperse evenly, creating a fluid mass: "It contains minuscule cocoa particles (mean diameter ca. 0.016 mm) and sugar particles too small for our tongue to notice them as grainy when properly distributed. The sugar is hydrophilic (water loving), and repelled by the fat. An important function of the lecithin emulsifier is to build protecting layers around the sugar particles so that they don't separate from the fatty phase and give a grainy texture. The emulsifier is commonly lecithin (lecithin is also a natural constituent of egg yolk, and the main reason for why the yolk doesn't split into a fatty and a watery phase).
In it's solid form, pure chocolate is a relatively stable system virtually free of water (0.5-1.5% by weight). When the chocolate is melted, the stable dispersion is challenged. If just a small amount of water (or steam) finds its way into the chocolate, the water molecules form droplets, since they don't want to mingle with the fat. Since water and sugar like to mingle, the sugar particles are wetted by the water. The result is "the sugar bowl effect", just as when a few drops of water are spilled into a sugar bowl. The tiny sugar particles in the chocolate become moist and cling together giving larger lumps (agglomerates). The result is an inhomogeneous mixture between these sugar agglomerates and the cocoa fat mixture. These won't mix evenly because the sugar has gone watery (the lecithin is probably not capable of stabilizing such large amounts of hydrophilic constituents). Since sugar is a major ingredient in chocolate, it all goes grainy. A water content of 3-4% by weight is enough to make the chocolate seize."
Reversing the seizing reaction means adding just enough water (or other liquid) to dissolve most of the sugar particles in the seized chocolate clumps, and turn it silky smooth again:
"What happens is that the emulsion inverts; whereas fat was the continuous phase in chocolate, now water is the continuous phase and the fat is distributed/"dissolved" in the water.'
How much is needed?
"In Beckett's book (The Science of Chocolate), he writes that about 20% by weight water vs. chocolate is needed to achieve such a phase inversion. Note that this is total amount of water; if cream, butter or some other water-containing ingredient is used, this contribution counts." from Fooducation. org, October, 2012
How to fix seized chocolate
Gray Bloom or White Streaks: If at any time the chocolate is heated beyond the tempering zones, it will burn or a gray "bloom" or white streaks will appear on the outside when cooled. Repeat tempering process.
Fat and Sugar Bloom, in general: Problems with fat and/or sugar caused by improper tempering; uneven cooling; storage of elevated temperature or fluctuation; abrasion or finger marks; fat migration from the centers of filled confections (nut centers - oils from nuts migrate to surface); humid storage conditions; direct contact with water.
Fat Bloom: The most obvious type of bloom, fat bloom, occurs when the structure of the fat crystals changes during too-warm storage. It looks like gray-white swirls or streaks on the chocolate when it is exposed to heat during storage, usually warmer than 75 degrees F. Storage at a constant, cool temperature is recommended.
To keep the chocolate cool, you can freeze it, but then you have to worry about the second type of bloom, called sugar bloom.
Sugar Bloom or Crystallization: occurs when the sugar crystals are affected by moisture. This happens when the chocolate is stored in damp conditions, either from humidity in the air or condensation from refrigeration, causing sugar to dissolve and come to the surface, which leaves it rough. It is visible as white streaks and dots and grainy texture. When the water evaporates afterwards, the sugar on the surface recrystallizes into rough, irregular crystals on the surface. You can prevent sugar bloom by preventing temperature shocks. When chocolate comes out of a cold room, it should be stored in a warm area long enough before opening the package to keep direct condensation from forming.
Stripes: The chocolate is not properly mixed during melting or tempering. Stir thoroughly before and during the process.
Molded chocolate is dull: when removed from its mold. The biggest cause is that the chocolate was not tempered properly. The molds were not polished well, or items were left in refrigerator too long after hardening; The molds were too cold. The filling was too cold; The workshop was too cold
White marks appear on demolded items: Make sure molds are completely dry before filling. Water can become trapped in molds with heavy patterns.
Molded chocolates crack: If molded items are placed in a refrigerator that is too cold, the chocolate contracts too fast and they will crack; The coating was too thin and cooled too quickly
Difficulty unmolding: The coating was incorrectly tempered; The coating was too thin; The cooling temperature was too high; Excess dried chocolate on outside of mold blocking unmolding
If the molded chocolate sticks to the mold when unmolding, it is probably too warm tempered properly.
Always swipe the opening of the mold with the edge of an offset spatula or bench scraper to clean. Do this right after pouring the chocolate while it is still warm and fluid.
If necessary, carefully scrape excess from the mold with the edge of a small, sharp knife. (You can always smooth knife dings with a warmed offset spatula. Lightly pass over ding.
Whitening or graying of chocolate: The coating was incorrectly tempered; The coating solidifies too slowly; Overcrystallized chocolate
Thickening of coating while working: Excessive crystallization in the chocolate
Fingerprints on finished products: The chocolate has been touched with warm or moist fingers. Make sure hands are dry; Use thin, cotton gloves when necessary.
Ganache can be temperamental because it is an emulsion: Bakers ask me a lot of questions on how to solve problems with their broken, greasy and problematic ganache mixtures. To solve their problems, since ganache is an emulsion, I did some research on emulsions and what brings them together and breaks them apart.
Curdles: Ingredients overmixed
Gently mix in a couple of tablespoons of hot cream, keeping the whisk submerged so as not to add air. Then, strain.
Use Steady, gentle mixing (agitation) is essential in reducing the fat to tiny droplets. Aggressive mixing causes graininess. Strain and re-stir if necessary. If it does not work, toss and start again.
Hardens after making, sitting and/or refrigerating
Poured Ganache: If it becomes too hard, place bowl over a pan of hot water and lightly stir until just reheated--don't whip because you don't want to whip the cream. Whipped Ganache: Try and beat a second time. If too cold, it will be too stiff, so rewarm. Place in a bowl of hot water or place back over a simmering pot of water for just a few minutes until the bowl has warmed. Remove from heat. Stir ganache until melted. Beat.
Separates Temperature of ingredients not compatible
High and low temperatures can break an emulsion. The emulsion of ganache starts when you start stirring the melted chocolate and cream together. If the mixture is too hot (above 110 degrees F) when you start mixing, you''ll start to see the fat molecules sitting on top of the mixture, an indication that the fat is starting to separate out of the mixture. In that case, slowly add a small amount of cold cream to the ganache and stir gently. This will recrystallize the chocolate's fat molecules and bring the mixture back together. If the mixture is too cold, and hard to mix, gently warm the mixture on top of a double boiler, until it is easier to stir.
Gets Dull and Cracks: Temperature of dessert not compatible
Many times ganache will dull from refrigeration; to make it shiny again, after refrigeration, use a hair dryer on low making sure you do not keep it pointed on one place otherwise you will melt the ganache glaze. I also find adding a little corn syrup or even butter to the ganache also helps to keep it shiny.
Strain mixture through a fine mesh strainer. You may have to do it several times. Stirring with a spatula or spoon creates tiny air bubbles. We use a small burr mixer (otherwise known as a hand or immersion blender). Make sure the blender head stays under the surface of the glaze while blending.
Does not firm: Cream was not boiled
Bring cream to a boil for a minute or more. It reduces the water content in the cream and breaks up the protein strands. Emulsified sauces combine better when the amount of water is reduced.
Bubbles: Overwhipped or using a spoon or spatula
Stirring with a spatula or spoon creates tiny air bubbles. Use a small burr mixer (otherwise known as a hand or immersion blender). Make sure the blender head stays under the surface of the glaze while blending.
Coating cracks: Centers are too cold
The coating on truffles will crack when it sets if cold centers are dipped into the warm tempered chocolate or any other coating. Allow the dipped truffles to sit at room temperature until the temperature of the centers has stabilized (about two hours) to dip them again. They should show no cracking after the second dipping.