I read about tempering in different resources and I see different temperatures stated.
For dark chocolate, some online articles say melt to 55c, others 45c.
The book I read "Chocolates & Confections" say 50c.
Why are the differences? What are the true temperatures for dark, milk and white?
The answer is 'it depends' 8-) there's a great deal here posted already on tempering, so i'll not rehash that - you'll need to do some digging here to find it. But suffice it to say that due to differences in cocoa butter compositions (not all cocoa butters are equal), and the influence of other soft fats (milk fat, nut fats, emulsifiers, etc), and 'degree of temper' - you're going to end up with a range. Very sophisticated operations have the ability to control their raw materials streams and the knowledge to narrow down that range quite a bit, but for the average joe, that's just not necessary
To follow on with what Sebastian has said, there is no "one, true" temperature for dark chocolate, one for milk chocolate, and one or white chocolate. Every chocolate will have its own set of working temperatures ... but those may change depending on the ambient temperature and humidity and the method of tempering being used. In large industrial processing situations they can control these variables very closely, but in the average small chocolate kitchen it's a different story.
In my experience, there is no substitute for being able to hand temper and to know what tempered chocolate looks like and how it behaves. You use that experience to help you arrive at the temperatures that work for you.
Okay I understand.
Thanks for the insight!