One of the many nightmares a chocolate maker has is whether his/her chocolate is in temper. But what exactly is temper?
Any pure chocolate (having natural &/or added cocoa butter) has 6 different types of crystal structure; at molecular level. Each of these crystals are formed, multiply stay stable at different temperatures. However, the crystal structure that chocolate makers want is the Beta V. This crystal gives chocolate the nice shine & snap that we all know and love.
In order to obtain the Beta V structure, we must first melt the chocolate to 45-48C to "kill" all crystals. Then bring down the temperature of chocolate to 29-30C and bring the temperature up by about a degree or two and "stabilize" the chocolate at 31C. The above temperature range works for dark chocolate only.
This can be achieved so doing manually on a marble top counter or through an automatic tempering machine. Before molding begins, a chocolate maker with usually perform a "temper test."
It means the room temperature is checked and kept between 23C-21C, humidity is kept below 50% (this will automatically happen if you have split air conditioners installed.) Once the first two parameters are ok, a dab of chocolate is applied on parchment paper. If the chocolate sets within 5 mins at room temperature with a matt finish without any whitish streaks, it is safe to assume that the chocolate is "in temper" and ready to be molded.
If the temper of the chocolate is not right, the chocolate could have a dull finish with white/brown streaks and also have a crumbly texture.
It is also important to note, that once the chocolate is in temper, we need to mold it quickly and refrigerate it for the chocolate to set. Once ready after 45 mins of refrigeration the chocolates should pop right out the mold effortlessly.
Any drastic temperature fluctuation and the entire batch is ruined. There is a learning curve involved, but after several years its come to us naturally. If you're just starting out, my advise if to be patient and change only one parameter at a time to diagnose the problem you are facing.