This post is the third of an ongoing series on cacao, covering in detail the science and art of tempering (raw) chocolate. Read previous posts in this series:
- Part 1 – The Story of Cacao: Origins, Varieties and Processing
- Part 2 – Cacao for Your Health: Three Perspectives
CONTENTS (click to jump)
- What is tempering?
- Why temper chocolate? Characteristics of properly tempered chocolate
- Recipe for tempered ‘raw’ chocolate – 75% dark
- Troubleshoot guide
What is tempering?
Tempering chocolate is the act of heating and cooling chocolate to specific temperatures to align fat molecules in cacao butter to the desired crystal structure (Form V) so that when it sets, the chocolate has desirable aesthetic properties and stable shelf-life.
The Science:
Source: compoundchem.com
Cacao butter in chocolate is a polymorphous fat with six different crystal phases, referred to as Forms I-VI, each with its own configuration and melting temperature. What is a crystal? Crystals are solids that have a regular repeated patten of molecules. Each crystalline arrangement leads to different physical properties of the substance. In chocolate, the preferred polymorph is Form V, which has a strong molecular network that manifests in desirable attributes, as explained below.
Why temper chocolate? Characteristics of properly tempered chocolate
We temper chocolate in situations where we want a professional-looking product with a fine texture, glossy sheen, nice snap and stable shelf-life. If you are making chocolate for home consumption, you need not temper since the chocolate will stay in the refrigerator for the most part and aesthetic qualities are not as important.
Tempering enhances the structure of chocolate and gives a satisfying snap
Because Form V crystals have a strong crystalline network, it takes more physical effort to pull them apart. This is why when well tempered chocolate is broken apart, you hear the characteristic snap. Polymorphs I-IV have an unstable, less organised and looser network so untempered or poorly tempered chocolate breaks apart easily.
Tempering enhances the appearance of chocolate and gives a glossy sheen
The stable alignment of Form V crystals results in the glossy sheen on the surface of well tempered chocolate (shine will only occur when it hardens against a shiny surface such as a polycarbonate mold). Untempered or poorly tempered chocolate appears dull or matt, and over time, white or grey patches may start to appear on the surface. The latter is known as a phenomenon called fat bloom, caused by migration and recrystallisation of less stable lower polymorphs from the centre to the chocolate layer.
Tempering enhances the mouthfeel of chocolate
Form V crystals are the finest of the cacao butter crystals and creates a smooth and even texture of chocolate. Untempered or poorly tempered has a grainy texture.
Tempering increases the melting point of chocolate and improves shelf-stability
The higher melting point of Form V crystals means it will not melt in your hands and the product has a stable shelf-life. Untempered or poorly tempered chocolate melts quickly upon contact with the skin.
Though untempered or poorly tempered chocolate does not affect the taste as much as its appearance and texture, the softer chocolate is more difficult to work with and makes a poor impression on tasters.
Recipe for tempered ‘raw’ chocolate – 75% dark
- Double-boiler or dehydrator
- Metal spoon for stirring
- Digital thermometer (probe or infra-red)
- Marble or granite surface (optional)
- Chocolate molds
- Metal scraper
- Pastry bags (optional)
- 150 g (1 1/2 cup) raw cacao butter, finely chopped
- 108 g (1 cup + 2 tbsp) raw cacao powder
- 84 g (5 tbsp) maple syrup* or finely ground coconut sugar* (see Notes)
- 86 g tempered chocolate, finely chopped, for seeding (optional, use up to 25 percent total weight of the melted chocolate)
- Pinch of sea salt (optional)
- First ensure that every utensil you use is completely dry. Moisture will cause the chocolate to seize and ruin your chocolate. Also avoid tempering chocolate on excessively hot or humid days.
- The purpose of this step is to melt all existing crystals and start with a virgin product. Place finely chopped cacao butter, cacao powder and sweetener of choice into a metal bowl. Using a double-boiler or dehydrator, heat the mixture gently and gradually to 46°C (115°F). If using a double-boiler, make sure the bowl covers the entire surface of the pot and does not touch the water directly. Stir the melting chocolate continuously as it warms and constantly monitor the temperature.
- Never allow the temperature to exceed 49°C (120°F) otherwise the chocolate burns, loses its molecular structure and crystalline potential and can not be used. When overheated, sometimes you will see the cacao butter separate from the powder and turn into a grainy mess.
- Once you achieve the goal temperature 46°C (115°F) for dark chocolate, immediately remove the bowl from the heat source.
- The purpose of this step is to bring the temperature down to form crystals IV and V. There are three common methods for cooling: seeding, tabling or cooling naturally by stirring.
- Seeding with tempered chocolate
- Add in the seeding chocolate gradually into the melted chocolate, stirring to completely melt each addition before adding the next. This helps to gently cool the melted chocolate and has the benefit of introducing strong Form V crystals into the melted chocolate, thus “seeding” it artificially instead of forcing it to form its own V crystal seeds. This is the method that I find most appealing.
- Seeding by tabling
- Spread 2/3 of the chocolate mixture out onto a cool surface, such as polished granite or marble, with a large scraper and icing spatula. Agitate it with for about 5 minutes or until it thickens, which indicates it has cooled to about 28°C (82°F). Return the cooled chocolate back into the bowl and mix together. This results in all the chocolate being properly.
- This is the preferred technique for most chocolatiers and works well for tempering large quantities of chocolate. However, most people do not posses a large marble slab and is not popular for small-scale chocolate-making.
- Seeding by stirring
- You can let the bowl of chocolate cool on its own by stirring continuously. However this can take up to 30 minutes or longer. The cooling can be sped up by placing the bowl into the refrigerator. However, remember not to cool it too quickly or it will form the undesirable crystals I-IV. Let it take at least two to three minutes to come down to 28°C (82°F).
- The purpose of this step is to reheat the chocolate to just below the melting point of Form V, [33.8°C (93°F)] to melt Forms I-IV, but not the Form V crystals. When the chocolate is again allowed to cool, it solidifies following the pattern of the existing Form V crystals so that the entire chocolate bar has the desirable crystal V phase.
- Return the bowl of chocolate to the double boiler or dehydrator and heat for just a few seconds. Watch the temperature closely as you stir continuously until it reaches 31°C (88°F). Remove the bowl from the heat source immediately.
- If you do go higher than the goal temperature by more than a degree or two, your temper is ruined. You can salvage the situation by repeating the process from step 1.
- Test to make sure your chocolate is properly tempered. Smear a thin layer of the chocolate onto a piece of parchment paper or aluminIum foil and let sit for 3-5 minutes. Now examine it. It should be even in colour with no streaks or spots, glossy but not shiny and when touched does not smear or leave chocolate on your finger. If it meets all these conditions then your chocolate is properly tempered and you can now use it with confidence. If the chocolate is not tempered, the chocolate will still be liquid and/or will have a marble-like colour indicating the fat and cacao are still separated.
- Use your tempered chocolate to fill molds or create shells, enrobe confections or dip fruit. Dipped items need to maintain ambient temperature and never cold from the refrigerator as this will harden the chocolate from the inside-out and turn it dull and gray. Allow your chocolate creations to cool at room temperature. Do not place into the refrigerator or freezer or the wrong kinds of crystals might form despite the fact that it has been tempered. You will find that well tempered chocolate solidifies rather quickly anyway, thus speeding the process along by chilling is unnecessary.
- The tempering process works best with a minimum of 1 pound (454 g) chocolate.
- You can play around with the ratio of cacao butter and cacao powder. I like to use 4:3 butter to powder, but you can use more butter for a thinner consistency (great for dipping) or more powder for a thicker consistency (will be more bitter also).
- Both maple syrup and coconut sugar are not considered raw products, but are mineral-rich and one of the less processed sweeteners. Coconut sugar has a lower glycemic index and gives a better snap, but suffers from being more grainy in texture. Maple syrup gives a more creamy chocolate with less snap. If you keep the liquid sweetener to less than 25% of total weight, the final product still has quite good temper. You can choose to use a mixture of liquid and granular sweeteners for a compromise of both worlds.
- If you prefer to use pre-tempered store-bought chocolate without the trouble of the heating-cooling process, simply melt and warm the chocolate to its correct working temperature - 31°C (88°F) for dark chocolate.
Temperature chart for tempering dark, milk and white chocolate.
Troubleshoot Guide
Seizing. Melted chocolate “seizes” when it comes into contact with moisture and forms a pasty mess. You cannot fix seized chocolate, but you can still use it in other applications where a temper is not critical, such as truffles.
Fat bloom. Fat bloom appears as a streaky film over the chocolate surface and is oily to the touch. It can result from a poor temper or a fatty center that is leaking oil through the shell. It caused by a poor temper, and/or migration and recrystallisation of less stable lower polymorphs or a fatty centre to the chocolate layer.
Sugar bloom. Sugar bloom appears as white-gray specks and is hard to the touch. It is usually the result of high humidity or condensation on the surface by putting it in the fridge or freezer, then returning it to room temperature. The sugar in the chocolate dissolves in the condensed water and as the water evaporates, the sugar comes out of solution, resulting in crystals on the surface of the chocolate.
The chemistry of fine chocolate is rather complex, but I hope this is a good foundation for you to start your journey into the world of being a chocolatier. Armed with this knowledge and know-how, you can have the confidence that your next batch of chocolate covered treats or molded chocolate candies will turn out beautiful and will be sure to impress.
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