Hi Calum,
You might want to verify that your packaging complies with EU and UK legislation concerning food safety. Any (packaging) material in contact with food is subject to these regulations.
Regards, Bart
Lee, I'm very curious about your results, I still haven't got a real clue to solve my sticking problem.
Someone advised me not to clean the moulds if possible, as the residual butter is supposed to help in the releasing of the next round. Confusing...
From my limited experience...
Flexibility of the mould can also lead to uneven release and cooling marks. I noticed this especially with large moulds with flat areas without much detail. As the chocolate shrinks back from the mould it releases on the edges and corners ok: there it cools first and the mould is more rigid due to it's shape. The middle of the chocolate is the warmest and solidifies the last, but as the mould flexes with the shrinking chocolate it doesn't release well or stick. When this happens to me, the chocolate will still release hard and shiny (sometimes I have to give the mould a quick tap to release), but you see visible cooling marks where the chocolate released in stages.
I can imagine better cooling will help too. But as I can't control my cooling very well, I don't know to what extent.
Do you know how your moulds are made: injection moulded or vacuumform and what is the material thickness? How complicated/intricate is your design?
I prewarm my moulds just above room temperature, that seems to give better results. I cool at 8-10degC with the moulds slightly raised, so air can circulate all around. On the 'to-do' list is to put a fan inside the cooling fridge, to see if forced air circulation gives better results. Now it can take some time (hours) before the whole piece has cooled sufficiently and the middle finally releases from the mould.
Hello Hassan,
Do you mean a product of 2kg? That is a big chunk of chocolate, what dimensions will this be? I've no experience with something that large.
Anything that is rigid enough and can withstand the heat from the plastic, can act as a pattern. I've used wood, plastic, aluminium, cast resin, epoxy coated styrofoam, even plaster for thermoforming.
Obviously a CNC router and thermoforming machine are a professional solution to make this type of mould. But you're looking at quite a large investment in money (guestimate: several thousand dollars) and time (learning how to operate this machinery). I don't have a CNC router (yet!): at the moment I let somebody else do the CNC routing for any shapes I can't make myself.
PET thickness will depend on size, shape and complexity of your design. As you stretch the warm plastic over your pattern, it will become thinner in some places. For some shapes 1mm is ok, for others I use 2mm. E.g for large flat shapes I prefer 2mm, as it is more rigid than 1mm and there is less chance of cooling spots on the chocolate. But thicker plastic will need higher vacuum for good reproduction of small details and corners on the pattern.
My vacuum forming table is giving me good results for what I do, I make moulds for small shapes with simple geometry (largest so far was 20x20x5cm). First upgrade will be a better vacuum pump so I can use thicker PETG.
With thermoforming it is as with making chocolate ;-) There is no foolproof recipe: sometimes things don't work and you don't know why. Then you need some feeling and experience to balance all parameters for good results.
Best regards, Bart
Hello Hassan,
Maybe you can expand a bit on your requirements?
I'm not entirely sure if you want to make the mould yourself, or if you want to order them? Is it a complicated pattern you want to make, how many moulds, how many products per mould?
If you want to make something yourself, I'd look into vacuforming thermoplastics. It's not a very complicated process and doesn't need special machines: with basic woodworking skills, some tools and time it's quite feasible to do yourself. I find that PET-G plastic sheet is cheap, easy to work with and produces excellent moulds: they're definetely clean and clear ;-) Be aware that vacuforming has some limitations: it's not suited for every shape and the quality of the mould will depend on the quality of the pattern (e.g. any roughness in the pattern will show on the chocolate) and the quality of your vacuform table (better vacuum gives better reproduction of the pattern).
There are lots of videos on Youtube about vacuforming and building a basic vacuform table, those should give you an impression of the process. Just let me know if this is what you're looking for?
Cheers, Bart
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.
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
