Can you tell me more about the immersion blender and what it does for this process? Just moving the chocolate around so it cools more and faster?
When you temper on marble you can see the temp. change happening as the chocolate thickens. It's a no brainer when you've reached your low temp. Then when you reheat it back to working temp. 90 or 92 it takes a while to do this gently and sometimes you get small clumps that don't want to stir out at that temp. If you use your stick blender it breaks down those bits nicely, giving you a nice smooth bowl of chocolate in seconds.
When you use the seeding method it's hard to get the temp. of your bowl of chocolate down stirring it (I think it takes longer). I reach a point where the seeded chocolate almost refuses to continue melting. You can stir and stir and it takes forever to get the whole bowl liquid.
With my stick blender I can force the chocolate into temp. changes more dramaticly. After I've reached my highest heat melting, I dump in my seeding chocolate and using the emursion blender it quickly breaks down the seed chocolate (even though I start with pistoles). I can go down into the 80's (seeing the temp. change clearly) even well below my targeted temp. and the chocolate remains more fluid. That makes reheating back to 90 or 92 take moments and I don't have any clumps to struggle with melting.
P.S. The correct tempering temp.s are written on or enclosed in your box of chocolate..........chocolate brands differ in the temp's they reccomend, it's not just authors.