During the winter period and particularly around Christmas and Valentines, is when demand for chocolate-based items, are at their highest. And for those of you at college, I know it is likely to be part of your current curriculum. Perhaps the task that most chefs fear is tempering. So, let’s look at why we need to do it and how to master it.
Cocoa butter is a complex fat that can set in different ways. In order to get the desired stability, melting point, snap and shine we must force it to set in a particular crystal format. This is achieved by melting the cocoa butter to de-crystallise it and then rapidly cooling it to a set temperature where the desired crystals will develop.
When you buy chocolate or couverture, it comes tempered. But each time we melt it, we de-crystallise the cocoa butter and must follow the tempering process. The longer the chocolate is melted the better the de-crystallisation will be and the more fluid your end result will be even after tempering to the same temperature. At Valrhona we recommend melting for at least 12 hours, either by loading your machine or melting tanks the day before or cover in a bowl and leave in a dry proover or set an oven at 40°C with a low fan speed.
Once the chocolate is melted to the required T1 starting temperature, then we need to decrease the temperature rapidly to T2. This is to keep all the different components separate and set them at the same time.
In lay man’s terms I like to imagine a wedding. As a wedding reception slowly goes on, gradually you will find the young guests on the dancefloor, the middle-aged blokes congregating at the bar and the oldies sitting in the corner or sleeping. Similarly, if we left chocolate to slowly set, the cocoa butter would float to the surface and set, sugars will separate from the other solids etc. By rapidly reducing the temperature, all these components remain mixed up.
Unless you are lucky enough to have a tempering machine, you need to manipulate the chocolate manually. There are 3 main ways to do this.
- Ice-bath; necessary in some countries or kitchens, but fraught with danger. First from excessive cooling of the chocolate on the outside of the bowl and from introducing water to your work space. A real last resort!
- Seeding; because the couverture comes tempered, if you add around 1/3 of unmelted feves to your melted chocolate. This will simultaneously decrease the temperature and introduce the desired crystals. However, this often develops too many crystals and there is a danger of incorporating humid air. So, this method is only advised for small quantities for decoration.
- Table; the best method of manual tempering, producing consistent and stable results. Often thought of as tricky or time consuming, but with a few tips and tricks, you can master this technique and realise it is neither.
T1, T2, T3
No, we are not checking in for an international flight. These are the key temperature control points. But they will differ when using the various brands and types of chocolate available. Most bags of couverture we use in commercial kitchens will have their advised temperatures on the label, likely displayed as a tempering curve.
But why are they different? It is cocoa butter that we are tempering and crystallising after all, and it is present in all couvertures. Cocoa butter alone forms the ideal crystal structure at 33.4°C. However, sugars and dairy present in couvertures block this process. So, the more sugar and dairy, the harder it is to crystallise and the cooler we have to go to create sufficient crystals. Hence why milk, blonde and white couvertures are tempered at lower temperatures.
I lost my temper! What has gone wrong?
I hope, with the tips I have given, you will find more confidence and control in the process. But inevitably sometimes you will lose your temper, because the couverture lost its temper! Usually this manifests itself in the form of bloom, but there are two types.
Fat bloom – this appears on the surface of the product and looks like a white mould. It is actually the cocoa butter setting separately as the result of not enough crystals being developed, either because the couverture was too warm, or the storage was too warm afterwards. Tempered couverture takes up to 24 hours to become stable, so correct storage is particularly important during this time.
Sugar bloom – this appears in the couverture as a kind of silver slug trail. This can be either a combination of T2 & T3 being too cold, so sugar crystals develop and are not melted. Or more likely humidity in the work space or storage, meaning condensation forms and dissolves the sugar. When it later evaporates, the sugar crystals are left behind as a tell-tale mark.
Lecithin for fluidity…
Couvertures contain lecithin. Lecithin is best known as an emulsifier and does indeed help keep chocolate stable in the manufacture and transport. But it also helps fluidity, by helping cocoa solids slide past each other when the chocolate is melted. That is why it is better to leave the chocolate to melt overnight to allow the lecithin time to give this fluidity. Be careful; many couvertures contain soya lecithin that will require declaring as an allergen. Valrhona has switched to using sunflower lecithin, which is both sustainable and avoids allergen issues.
Chocolate or Couverture?
Couverture is often described in the UK as cooking chocolate, which is correct in a sense. It directly translates as a blanket or cover as it is a high-quality chocolate that usually contains added cocoa butter to improve the fluidity, giving a thin shell and higher shine when ‘covering’ ganache.
Couverture is subject to legal definition as containing not less than 35 per cent total dry cocoa solids, including not less than 31 per cent cocoa butter
Top tips for table tempering
- Use a marble or granite table. Guaranteed to be flat and always a little cooler than the room. Make sure its clean but dry. TIP- if you will temper multiple chocolates, start with lighter coloured ones first. That way you can wipe the table between without requiring a deep clean with water. Though you should consider allergen cross-contamination.
- The work environment ideally needs to be 20-22°C with 60% humidity. Not always easy in commercial kitchens, so the closer to this ideal you can be the better your results will be. Consider doing all you are tempering on quieter days, or early in the morning before the heat and humidity rises.
- Heat your couverture to T1. Pour ¾ of the couverture onto the table and keep the remaining couverture to one side. You need to move it around to stop it setting, but that doesn’t have to mean moving fast with multiple implements. Train yourself to work one handed. That way you can always use a thermometer to monitor the temperature, like my colleague Romain in the photo. If you wait for the chocolate to begin to set on the table, it is often too late, and you will have too many crystals.
- When the chocolate reaches T2, move it into a clean bowl. Check the temperature once its back in the bowl, as the table will give you a false reading.
- At T2 the desired crystals will begin to form, along with some unstable crystals. So, to limit those we warm the chocolate slightly to T3. Add the warm un-tempered couverture you set aside before, little by little. This will both raise the temperature and control the amount of crystals present, keeping the tempered chocolate fluid for longer. Keep using this couverture to maintain the temperature
- Use the couverture as required. Remember even tempered chocolate is only a shiny as what it sets next to. So, make sure moulds are polished and acetate is clean. Or use silicon paper for your décor for a satin effect.
- If you have excess couverture from your décor or from moulds, never add it back to your tempered chocolate as it will accelerate crystallisation and make your chocolate thick. Keep it separate, you can then re heat it and use to top the tempered couverture back up once your reserved
- For the best décor results, spread the couverture between two sheets of acetate, then wait for it to begin to crystallise before using a cutter or blunt knife to score the chocolate without cutting the plastic. This technique ensures that the couverture is very thin, but also being stored between the two sheets of acetate protects it from dust and moisture too.
- When you’re finished, one common mistake is to put the couverture in the microwave while you clean the table. That takes it out of temper and worse still, sometimes burns it. Chocolate is best stored tempered, as it is less prone to humidity and odour absorption. So, the best thing to do is to leave it tempered and pour it between 2 sheets of greaseproof. It will set quickly and when cooled can even be sous-vide. That also makes it easier to chop for re-melting next time.
Valrhona Pastry Chef Instructor – Northern Europe