Hello all,

I hope I'm not asking something which has been asked before (I did a search), but hopefully someone can help a beginner out. It gets a bit frustrating having to melt back half of your work ;-)

Here is what I'm trying to do:

I made some custom moulds (PETG) of a logo, for casting a tablet. The mould has several shallow cavities (about 2millimeter or 0.1 inch) for different colours of chocolate: small details in dark, and larger area's with white and milk.

First I fill in the small details with dark, then a few larger areas with white and finally milk (using piping bags), tapping the mould each time to get bubbles out and fill the cavities. After filling in the logo, the rest of the tablet is topped off with milk or dark. Total thickness is about 14mm, just over 1/2 inch.

The problem I'm having is a some sticking and 'flaking' of the white chocolate in small spots, ugly! The milk and dark release nice and shiny. I'm a bit stuck: I tried a few things but running out of ideas.

Moulds were cleaned and polished (very thoroughly!) with cotton wool in between.

I believe the temper is ok: the white chocolate sets up nicely. Sometimes it shows some 'cloudiness' or swirls where it comes from the piping bag, maybe it's overcristallised? (Although I try to keep it in control with the heatgun before pouring).

I tried preheating the mould (room temperature is about 19degC), but that doesn't seem to help. Also it takes a lot of time to put all the colours in, so the mould is probably cooled down anyway. Reheating is not really possible as the other colours become fluid again and start mixing when pouring the next colour...

I tried working fast, pouring one colour after another. And I tried working slow, letting one colour solidify before applying the next one (with a quick run of the heatgun in between to make the layers stick together). Fast or slow didn't seem to make much difference in succes rate...

Any tips how to tackle this? Is white chocolate more difficult to work with than milk or dark? And should I work fast, or is it ok to have previous layers semi-solid and then pour a new layer on top?

I'm also not sure anymore what the proper cooling procedure is: should I pop it in the fridge straight away or let it cool down first at room temperature?

Thanks, Bart

updated by @bart: 04/19/15 01:03:31

I'm a novice as well... Might try first painting/spraying a thin coat of cocoa butter on the mold? That's something I've done to have a uniform shine once released from mold. Perhaps it will help keep the white together.I think if the chocolate you are using is in temper, it shouldn't matter if the previous layer is set.Also, I try to steer clear of the fridge, due to high humidity. Once set up, I put the mold in the freezer for five min.Best wishes!

Thanks for your trouble Ashley. I don't have any cocoa butter here, but I'll try this next time.

But hopefully things are under contol again, the first batches look promising: dropping right out of the mould and nice shine. It's probably a combination of things that causes problems:

-I washed the moulds with NaOH, great tip I found on this forum.

-Maybe I was overheating the moulds, I do a more gentle preheat at lower temperature.

-Keeping an even tighter check on the temper of the white chocolate. I guess it was overcrystallizing when I got to the last moulds.

With my fridge I'm not too worried about moisture, this one keeps the humidity low.