Shirley O. Corriher
American Chemical Society
New York, October, 2007
Cocoa butter, the fat in chocolate, can crystallize in any one of 6 different forms (polymorphs, as they are called). Unfortunately, only one of these, the beta crystal (or Form V), hardens into the firm, shiny chocolate that cooks want. Form VI is also a stable hard crystal, but only small amounts of it form from the good beta (Form V) crystals upon lengthy standing. When you buy commercial chocolate it is in the form of beta crystals.
When you melt chocolate and get it above 94° F, you melt these much desired beta crystals and other types of crystals can set up. If you simply let melted chocolate cool, it will set up in a dull, soft, splotchy, disgusting-looking form. Even the taste is different. Fine chocolate has a snap when you break it and a totally different mouthfeel from the other cocoa butter forms.
How can we get chocolate to set up in these hard, shiny beta crystals? The process of melting and then cooling the melted chocolate so that it will form beta crystals is calledtempering. Tempering is necessary only for real chocolate which contains cocoa butter, not for compound chocolate or summer coating which contains fats other than cocoa butter.
You need a truly accurate thermometer. Most kitchen thermometers (even the digital instant-read type) can be off by 10° F. If you do much chocolate work you'll want a laboratory quality thermometer.
When I asked chocolate expert Dr. Paul Dimick about tempering he said the easy way is to never heat chocolate over 91° to 92° F. Beta crystals do not melt until 94° F. So, you never lose all of these prized crystals and your melted chocolate is already tempered. What a wonderful idea!
Your goal is to barely melt the chocolate. All of these crystals have a range over which they melt and chocolate melts at 89° to 90° F even though all the beta crystals do not melt until above 94° F. You can keep the chocolate over a very low heat source and, with constant stirring, melt 2/3 of it. Then, remove it from the heat and patiently continue stirring until all the chocolate is melted. For dark chocolate, ideally you want to end up with a temperature of 89° to 91° F (87° to 89° F for milk or white chocolate). If you have kept the chocolate below 92° F during all of this, it is still tempered and ready for use.
You need to grate the chocolate or process it in the food processor until it is finely chopped so that it will melt evenly. Place it in a metal bowl and heat with very low heat. Constant stirring is a must. Some chocolate experts set up a heating pad on low or a small coffee warmer or hot tray. Some like to microwave the chocolate in short time intervals with frequent stirring (50% power for dark, low power for milk or white chocolate)--any way that you can keep the heat 90° to 92° F. You can use a warm water bath but you must take great care not to get even a drop of water in the chocolate which will cause it to seize (see Seizing above).
If you get the chocolate over 94° F, you lose your prized beta crystals and you must go through the full tempering process. First, you must completely melt the chocolate. The risk here is separation. Chocolate can irreversibly separate into golden cocoa butter and grainy black cocoa particles. You can use the cocoa butter as a great hand cream, but your chocolate is gone. Most cooking literature advises you not to get chocolate over 120° F. Melting curves of chocolate in the technical literature indicate that most of the fats in cocoa butter are melted by 122° F. Some processors recommend heating their chocolate slightly higher--up to 131° F.
Cocoa butter, as most natural products, is a complex mixture of fats and contains small amounts of fats that do not melt until high temperatures--over 200° F. Dr. Dimick explained that cocoa beans from different locations are very different and that the plants adapt to the climate of their surroundings. At the same temperature, cocoa butter from Malaysian beans which grow near the equator is quite firm, while cocoa butter from Brazilian mountain grown beans which grow in a much colder climate is quite soft. Dr. Dimick says one of the major factors causing separation is inadequate stirring.
Ideally, consult the chocolate processor for the best temperature for your chocolate. As an overall temperature, I would suggest melting dark chocolate no higher than 122° F (110° to 118° F for milk or white chocolate) with constant stirring.
Now, the chocolate must be rapidly cooled to about 82° F for dark (79° F for milk and white). Always use constant stirring. Cooling this low does allow undesirable beta-prime crystals to form, but it gets good crystallization of the beta crystals started. Now, the chocolate is warmed gently to raise the temperature to 86° F for dark (84° F for milk and white). It should be held at this temperature for a few minutes, then warmed up to 91° to 92° F for dark (87° to 89° F for milk or white). Bringing the chocolate up to this higher temperature melts the undesirable beta-prime crystals that were formed.
There are a number of methods to achieve this rapid cooling. Regardless of the method, the one thing that you must do is to stir constantly. Some chefs like to spoon 2/3 of the chocolate out onto a cold surface like a marble slab and scrape the chocolate back and forth with a spatula until it is about 82° F. One must work fast doing this and it is difficult to get a quick temperature reading on the slab. Then, the cooled chocolate is blended with the warm reserved chocolate to bring it back to the desired temperature.
Dr. Dimick uses a cold water bath. He places the stainless steel bowl of melted chocolate into a bowl of ice water and stirs constantly until the chocolate cools to 82° F for dark (79° for milk or white). Then, he warms it to 86° F for dark (84° F for milk or white). He lets it remain at this temperature for a couple of minutes then heats it back up to 91° to 92° F for dark (89° F for milk or white).
A fairly simple way to lower the temperature fast is to stir the chocolate with a big lump (3-inches or so) of tempered chocolate or grated chocolate. This melting chocolate both cools and seeds with the right kind of crystals. You can lift out and reuse the lump of chocolate when you reach the correct temperature. If using grated chocolate to cool, add only a tablespoon at a time to insure that you do not end up with unmelted fine particles. Chocolate expert Alice Medrich uses a submersible blender to constantly stir while cooling, taking care to keep it submerged. This is certainly an excellent way to stir large batches of chocolate.
Some chefs like to temper melted chocolate by simply stirring constantly in a cool room.
Tempering machines have the advantage of constant stirring and accurate temperature control. I notice that some of the machines recommend placing a lump of tempered chocolate in front of the machine stirrer blade to seed the chocolate and encourage the growth of beta crystals. These machines are available for under $400 and are worth it if you do a lot of quality chocolate work.
If you use a dry method of heating, you avoid the risk of seizing that you always have with water baths.
There are a number of ways to check to see if your chocolate is tempered. Spread a smear out on a piece of waxed paper, if it dries shiny and hard within 5 minutes you are fine. Dr. Dimick uses the "string" test. After he has cooled and brought the chocolate to temperature, he spoons up a little and drizzles a string of chocolate on the surface. If it disappears instantly, he knows he does not have enough crystals formed to hold it up for a few seconds and it is not tempered. Stirring constantly with a lump of tempered chocolate may fix it. But, if it is simply not tempered and you have the wrong kind of crystals, you must begin again and go through the entire melting and cooling as described.
|Form I (beta -prime 2)||61° to 67° F|
|Form II (alpha)||70° to 72° F|
|Form III (mixed)||78° F|
|Form IV (beta-prime 1)||81° to 84° F|
|Form V (beta 2)||93° to 95° F|
|Form VI (beta 1)||97° F|
© Copyright Shirley O. Corriher, 2007
What It Is, How To Temper Chocolate and The Alternative
By Steve Leffer, Chocoholic & Chief Taster
Before you read further, please note that you DON’T temper chocolate when you are baking or are going to consume the chocolate immediately, such as melting and pouring over ice cream. We suggest that for the very best results in making candies and other dipped items, you temper the chocolate – even if it’s going to be used within 24 hours – especially if you want the chocolate to set up perfectly, to have a snap and a sheen, and if you want to coax the most flavor from the chocolate. If these details are not important to you, then you can use the chocolate without tempering if it will be consumed within 24 hours. And of course, you should use a superior quality Chocoley couverture chocolate.
If you don’t want to deal with the following steps, get yourself a nice chocolate tempering machine or try delicious Chocoley Bada Bing Bada Boom Gourmet Compound Chocolate — with that there’s no tempering required.
Now, about tempering…
How do you know if you need to temper chocolate? If you are using real chocolate (couverture chocolate made with cocoa butter) you need to temper except as stated above. When using compound chocolate, often referred to as coating chocolate, you do not temper.
If you are a mathematician or scientist, you’ll find the subject about tempering chocolate to be a simple concept. For the rest of us, the details are dull, boring, and sound a lot like mumbo jumbo or a bunch of nonsense. I made it all the way through college only taking one biology class, so its taken me a while to really grasp the concept of why the process of tempering produces the results that it does. To make matters even more complicated, every book, article or website I have researched about tempering chocolate has different methods or techniques for achieving this much desired “tempered state.”
The good news is, I am going to attempt to simplify and explain tempering so that you can understand it. If you are one of those mathematician or scientists mentioned above or already know this stuff, you can skip down to the methods of tempering below.
Okay, so what does tempering chocolate achieve?
When you temper chocolate, you’ll produce a finished product with a professional sheen, snap and taste – and your creations will not bloom when kept at the proper temperatures. Tempering is the process that re-establishes the cocoa butter crystals that are in real chocolate (versus compound chocolate). So, what on earth does re-establishing cocoa butter crystals mean? Let’s think about liquids becoming solids. When water turns into ice, most of us think this “happens” because of temperature. In part, that’s true, but what really happens is that when the water temperature drops to 32°F, water molecules come together to form crystals, and all of those crystals attach themselves together to form a solid mass – ice. Just think about the shape of a snow flake. A snow flake is an individual ice crystal.
Chocolate, not unlike the description of water/ice, starts as a solid (when you get your hands on it), then you melt it, turning it into a liquid. Ultimately, you want it to turn back into a solid (unless your using it in a fountain or fondue…then you can ignore this stuff!) to create wonderful chocolate candy, molded items, dipped items, etc. But unlike water turning to ice, where nobody cares how or why it happens, we need to be concerned with how to properly harden the chocolate so that it has the best sheen, snap and taste and so that it doesn’t bloom or separate.
Wikipedia.com (the free encyclopedia) explains how the cocoa butter in chocolate can crystallize in six different forms. The primary purpose of tempering is to assure that only the best form is present. Below is the Wikipedia.com chart showing the six different crystal forms and their different properties, followed by an excellent explanation of what the tempering process is actually trying to achieve.
Crystal Melting Temperature Notes
I 17°C (63°F) Soft, crumbly, melts too easily.
II 21°C (70°F) Soft, crumbly, melts too easily.
III 26°C (78°F) Firm, poor snap, melts too easily.
IV 28°C (82°F) Firm, good snap, melts too easily.
V 34°C (94°F) Glossy, firm, best snap, melts near body temperature (37°C).
VI 36°C (97°F) Hard, takes weeks to form.
For the best possible finished product, proper tempering is all about forming the most of the type V crystals. This will provide the best appearance and mouth-feel and creates the most stable crystals so the texture and appearance will not degrade over time. To accomplish this, the temperature is carefully manipulated during the crystallization.
The chocolate is first heated to melt all six forms of crystals (heat dark chocolate to 120°F, milk chocolate to 115°F, and white chocolate to 110°F). Then the chocolate is cooled to allow crystal types IV and V to form (VI takes too long to form) (cool dark chocolate to 82°F, milk chocolate to 80°F, and white chocolate to 78°F). At this temperature, the chocolate is agitated to create many small crystal “seeds” which will serve as the nuclei to create small crystals in the chocolate. The chocolate is then heated to eliminate any type IV crystals, leaving just the type V (heat dark chocolate to 90°F, milk chocolate to 86°F, and white chocolate to 82°F). After this point, any excessive heating of the chocolate will destroy the temper and this process will have to be repeated.
Two classic ways of tempering chocolate are:
Working the melted chocolate on a heat-absorbing surface, such as a stone slab, until thickening indicates the presence of sufficient crystal “seeds”. The chocolate is then gently warmed to working temperature.
Stirring solid chocolate into melted chocolate to “inoculate” the liquid chocolate with crystals (this method uses the already formed crystal of the solid chocolate to “seed” the melted chocolate).
Thank you, Wikipedia, for the above valuable information, but let’s take it a bit further and define, step-by-step HOW to temper chocolate.
METHODS OF TEMPERING CHOCOLATE:
With the help from the good folks at baking911.com, here is their expert step by step instructions for three different methods of tempering (temperatures have been adjusted to reflect the best temperatures to work with Chocoley’s couverture and ultra couverture chocolates):
Traditionally, chocolate is tempered by pouring some of it on a tempering stone and worked into a “mush” as it cools. It results in the most glossy, crisp chocolate that will set with the most reliability and is recommended for the most demanding chocolate work. Before using, make sure the surface is a cold, clean and dry. If necessary, cool it by wiping with cold water and then dry it thoroughly, as tiny beads of water left on surface will cause the chocolate to seize.
- To temper, melt up to one pound of chocolate in a double boiler or use a double boiler insert. Use a thermometer to check the temperature of the chocolate; (Temperature guide: Dark chocolate 120°F, milk chocolate 115°F, white chocolate 110°F). Pour 2/3s on a cold table or marble surface. (Keep the other 1/3 at the same melting point temperature; do not let it harden).
- Using a pastry or bench scraper and angled spatula (offset spatula), spread the chocolate. Then move it to the center, clean the scraper with the spatula and spread continuously. Continue this spreading and scraping process until the chocolate cools to the following temperatures: dark chocolate 82°F, milk chocolate 80°F, white chocolate 78°F, which are a lower temperature than quick-tempering. It will lose its shine and form a thick paste with a dull matte finish. Work quickly so that the chocolate does not lump. This process can take anywhere from 2 to 10 minutes, depending on the amount of chocolate and the type, as well as the temperature of the kitchen. The professional term for this is “mush.”
- Add the “mush” from the previous step, to the remaining 1/3 melted chocolate. Using a clean, dry rubber spatula, stir the chocolate gently, until smooth. Be careful not to create air bubbles as you do. Return the mixture to heat, stirring constantly until the desired temperature is reached. For dark chocolate it should register 90°F for dark. For milk it should register 86°F and white chocolate should register at 82°F. Check temper before using.
- As you work, regularly stir the chocolate and check its temperature to keep it “in temper”:
dark chocolate 88-90°F
milk chocolate 86-88°F
white chocolate 82-84°F
Seed Method/Ice Cube Method*:
- MELT: Reserve 1/3 of the chocolate you plan to temper. The remainder is melted in a double boiler to no more than 120°F. Above 120°F, the chocolate separates, burns and can no longer be used. When cocoa butter crystals melt at this temperature, they lose their shape and the crystals become unstable, so Step#2 is necessary.
- COOL: The chocolate is then cooled by “seeding” or mixing in discs or wafers of solid chocolate because they are at a cooler room temperature of 68 to 70°F. The molten cocoa butter also does a kind of follow-the-leader and arranges itself after the fashion of the “seeds”, which are already tempered by the manufacturer. Don’t add too much at a time as it may not all melt and the mixture will become lumpy. If it does, use an immersion blender which is invaluable, or strain the lumps out, which is trickier. Don’t use a mixer. The key is to keep stirring rapidly and to take its temperature frequently until the proper one is reached. This gets the crystallization of the good beta crystals started, but it does allow some undesirable beta-primes to form, too, so go to Step #3.
- REHEAT THE CHOCOLATE: in the double boiler so it will harden with a perfect consistency. Here reheating melts any of the undesirable crystals that are formed in cooling during Step #2. When it reaches the desired temperature, the chocolate is now tempered. If it is reheated to more than 89°F (milk) or 91°F (dark), it goes out of temper, and you have to start again from the beginning.
For advanced chocolate-makers, test the temperature by placing a dab just below the lower lip. It should feel just warmer than warm milk.
- CHECK TEMPER BEFORE USING: A simple method of checking if the chocolate is in temper, is to apply a small quantity of chocolate to a piece of paper or to the point of a knife. If the chocolate has been correctly tempered it will harden evenly and show a good gloss within five minutes. Or, spread a thin layer on a scrap of parchment, wait five minutes, and then try to peel the chocolate from the paper. If you can, and it’s not blotchy, you’re in business. If not, start the tempering process again.
- KEEP CHOCOLATE IN TEMPER DURING USE: Ideal temperatures are 88-90 °F for Dark; 86-88°F for Milk and 82-84°F for White. The chocolate will cool if not kept at a constant temperature, and gets thick and dull as is does. If chocolate cools too much and is still melted, you can reheat it multiple times back to “temperate zone” of 88 to 90°F (dark), 86 to 88°F (milk), 82-84°F (white). If the chocolate cools to the point of hardening, the tempering process must start again. Never let the chocolate’s temperature exceed 92°F, for the dark chocolate or 88°F for the milk and white chocolate, or the stable cocoa butter crystals will start to melt and the temper will be lost.
- *Baking911.com refers to the seed method as the ice cube method.
The Three Step Method:
Stir constantly during the steps and avoid having moisture from coming in direct contact with the chocolate:
- Melt chocolate, in a double boiler, to the following temperatures as measured with a chocolate thermometer: Dark 120°F, Milk 115°F, White 110°F.
- Cool chocolate to the following temperatures: Dark 82°F, Milk 80°F, White 78°F.
- Reheat chocolate to the following temperatures: Dark 90°F, Milk 86°F, White 82°F.
IT IS NOW TEMPERED. A simple method of checking if the chocolate is in temper, is to apply a small quantity of chocolate to a piece of paper or to the point of a knife. If the chocolate has been correctly tempered it will harden evenly and show a good gloss within five minutes. Or, spread a thin layer on a scrap of parchment, wait five minutes, and then try to peel the chocolate from the paper. If you can, and it’s not blotchy, you’re in business. If not, start the tempering process again. KEEP CHOCOLATE IN TEMPER: Ideal temperatures are: Dark 88-90°F, Milk 86-88 degrees F, and white 82-84°F. If the chocolate hardens, you must start the tempering process again.
Thank you Baking911.com for your expertise in this area. Unfortunately, every expert has their own opinion of the proper method and techniques for tempering. While they all seem to be relatively similar, they often state completely different melting, cooling and reheating temperatures. The things that seem to remain constant, regardless of the expert opinion is:
- Always use an accurate chocolate thermometer, and keep the temperature low; Always work in a cool environment with relative humidity of 50% or lower (our Indoor Humidity Monitor shows room temperature & humidity as well as highs and lows)
- Always use the right tools for the job
- Always test for temper, using the tip of your offset spatula
- Don’t worry, have fun, if the chocolate goes out of temper, you can always re-melt and start over, you didn’t hurt anything.
Oh, and one last thing, remember, if you don’t want to deal with all these steps, get yourself a good chocolate tempering machine or try delicious Chocoley Bada Bing Bada Boom Gourmet Compound Chocolate which does not require tempering.
Ready to try your hand at tempering? Here are a few items you may need: