To test for proper temper dip a small spatula or even a dinner knife into the chocolate until about 2 inches are coated. Allow the excess to drip back into the container.  Prop the knife or spatula so it can dry without touching any surfaces. Leave it at room temperature for five minutes if you are using dark chocolate. 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.  To learn more about testing for proper temper consider purchasing DVD volume one.

If you can keep your chocolate at its working temperature it will stay in temper for many hours. However over time it will become thicker as the beta crystals continue to multiply. Once your chocolate is in temper you can reheat it to keep it liquid enough for molding. Just make sure you don't let it get above the working temperature. 

No! Once your chocolate is in temper you have dissolved the unstable crystals and you have a predominance of stable beta crystals in your chocolate. As your chocolate cools, it will become thicker as the beta crystals grow and multiply. As it thickens you can warm it again either by heating with the heat gun or microwave, or by adding warm untempered chocolate. The beta crystals in the tempered chocolate will act as a seed to temper the newly added untempered chocolate.

You will be able at this point to heat it a degree or two higher than the standard working temperature in order to make it thin enough to work, without driving off all the beta crystals. Just be careful that you don't exceed about 34 degrees for dark chocolate, 32 degrees for milk chocolate and about 31 degrees for white chocolate. 

Yes. If you have chocolate left over after a session of molding you can re-temper it. Or if you have chocolate that you improperly tempered and it is streaky or spotty you do not need to discard it. Heat and cool this used chocolate just as you did the first time to bring it into temper but add about 10% new chocolate for best results. This will not work however for chocolate that has been contaminated by dipping things into it. Leftover chocolate used for dipping is best reused in a ganache or a bark.

That’s what we call bloom - if it is crispy to touch it’s sugar bloom, if oily it’s fat bloom.

Sugar bloom is usually the result of leaving chocolate in the refrigerator then when you take it out condensation forms on the surface.  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.

Fat bloom can result from poor temper or a fatty center that is leaking oil through the shell.

White chocolate contains a lot of milk fat along with cocoa butter. Milk fat crystallizes differently than cocoa butter and makes tempering white and milk chocolate more challenging than tempering dark chocolate. White chocolate is more susceptible to burning than dark chocolate due to the milk solids in it.  The temperatures involved in tempering white and milk chocolate are in general 2 to 4 degrees C lower than those for dark chocolate. 

When molding with white chocolate, make sure you test the temper of your chocolate and don't start molding until you are sure the chocolate is in temper. While you generally want a nice thin shell when you are molding with dark chocolate, with white chocolate a thicker shell will give a better result, especially if you are using thinner, more liquid fillings. Cool in fridge just long enough to set, don't leave in fridge for extended periods as this seems to encourage condensation and results in a dull finish. 

A stainless table doesn't have quite the same thermal mass as marble. So cooling is not going to be as effective as marble or granite.

Yes. But you will need to add a decent percentage of fresh, unbloomed chocolate to it to ensure you get a quality product.

When you add other fats to chocolate (i.e. peanut butter) you change the eutectics of the fat in the cocoa butter - that may explain the problems you are having.

No! Once your chocolate is in temper you have dissolved the unstable crystals and you have a predominance of stable beta crystals in your chocolate. As your chocolate cools, it will become thicker as the beta crystals grow and multiply. As it thickens you can warm it again either by heating with the heat gun or microwave, or by adding warm untempered chocolate. The beta crystals in the tempered chocolate will act as a seed to temper the newly added untempered chocolate. 

You will find if you have been working for many hours with your tempered chocolate that it seems much thicker at the same temperature than it was before. This is due to the multiplication of stable beta crystals. You will be able at this point to heat it a degree or two higher than the standard working temperature in order to make it thin enough to work, without driving off all the beta crystals. Just be careful that you don't exceed about 34 degrees for dark chocolate, 32 degrees for milk chocolate and about 31 degrees for white chocolate.