Tempering chocolate goes through three stages: dark chocolate is first melted to 45-50°C, then cooled down to 27-28°C, and finally brought back up to 31-32°C, its working temperature. The whole process usually takes about 20 to 30 minutes.
Why does it need three different temperatures?
Cocoa butter in chocolate can solidify into several different crystal forms, and only crystals formed within a specific temperature range give chocolate a glossy finish, a clean snap, and a texture that won't melt at room temperature. The initial melt wipes out every existing crystal, the cooling stage lets the right crystal type form, and the final reheat melts off the coarse, unwanted crystals while keeping the good ones intact.
How do the temperatures differ for milk and white chocolate?
Milk chocolate, because of its milk powder content, works at lower temperatures: melt at 40-45°C, cool to 26-27°C, work at around 29-30°C. White chocolate is the most delicate of the three — melting shouldn't go past 40-43°C, cooling should land at 25-26°C, and working temperature is 27-28°C. Overshoot any of these by even a few degrees and the temper breaks, meaning you have to start over.
How does the cooling stage work?
Cooling can be done by pouring roughly a third of the melted chocolate onto a cold marble surface and working it continuously with a spatula until it cools fast, then stirring it back into the rest of the warm chocolate. Done carefully, this stage takes 5 to 8 minutes; alternatively, adding pieces of already-tempered solid chocolate into the melted batch achieves the same cooling effect.
How do you know it's tempered correctly?
Drop a spoonful onto a sheet of paper and let it sit at room temperature without refrigerating it; properly tempered chocolate sets with a glossy surface within 3 to 5 minutes and gives a clean snap when broken. Chocolate that stays dull or shows white streaks (fat bloom) needs to be tempered again.
How long does it need to stay at working temperature?
Tempered chocolate needs to stay at its working temperature (31-32°C for dark) until it's poured into molds or used for dipping; drop below that range and it thickens and becomes hard to work with, go above it and the temper breaks. That's why larger batches are kept on a warming pad at a steady, low temperature while you work.
Why is the seeding method so practical?
One of the easiest home-kitchen methods is melting two-thirds of the chocolate and stirring in the remaining third as finely chopped, already-tempered solid chocolate; as those solid pieces melt, they seed the surrounding chocolate with the right crystal structure, giving a clean temper without needing a marble slab. Keep stirring until the solid pieces fully dissolve, and stop adding more once the temperature reaches the target range.
What kind of thermometer should you use?
Chocolate temperature should be checked with a digital kitchen thermometer that reads to a decimal point; a candy thermometer calibrated for a much higher range may not show the fine degree differences chocolate needs. Insert the probe into the center of the chocolate each time, away from the edge of the bowl, since edge temperature can read differently from the center.