Just started working with pulled and blown sugar and am getting some good results. However I seem to be facing a problem with contamination/purification. My sugar comes out fine, without crystalising, but has (to me) an unacceptable level of impurities in it. Here is my basic method:
+ Wash pot with soapy water and metal scourer, then rinse well and leave to dry naturally.
+ Wash SilPat with hot water (I've found that it sticks to my shower screen so I put it up against it and blast for 2 or 3 mins with the shower on max heat) and shake, then leave to dry.
+ 1 Kilo of sugar, 400g of water and 3g of cream of tartar over the lowest heat I can get.
+ When scum starts to float, begin scooping it with a mesh rehashed from an old tea strainer. When the majority of scum is gone, brush the sides to prevent crystals and increase the heat until the bubbles become more fierce, pushing any remaining scum to the sides where I scoop it with a teaspoon (rinsing between scoops of course).
+ Bring to above 160 degrees C. Pour onto SilPat and work as normal.
Is my problem in the way I wash things, impurities in the water, equipment used or what? Also, how much scum should I expect off 1kg of sugar, and how can I tell when it's bubbles from the boiling process and not just scum? I'd really appreciate some help on this.
Edited by StuartScholes - 6/18/13 at 10:19pm