How to make your own food-safe, PFAS-free ice cube moulds with silicone

Want to make ice cubes in your own shape? A standard ice cube or a large sphere for your whisky glass? Or would you rather go for something unique, such as a fish, a star or a cat? Then it all starts with the right mould. Silicone rubber is the ideal choice for this: it is supple, stretchy and captures every detail down to the smallest corners. A home-made silicone mould also lasts for hundreds of pours.

Why make your own ice cube mould?

There are plenty of ready-made ice cube moulds in the shops, but they all come in the same standard shapes. Make one yourself and you decide the shape, the size and the detail. You cast a mould of an existing object, such as a figurine, a piece of jewellery or your own logo, and then use it to make as many ice cubes as you like. Ideal for a party, an original gift or simply to make your drinks a little more special. And you can just as easily use the same mould later for chocolate or jelly.

What do you need to make a silicone mould?

You do not need much to get started:

• Liquid silicone rubber suitable for moulds. A food-safe platinum-cure silicone works best and holds every detail.
• The object you want to make the mould of
• A tub or box to act as the mould box
• Scales and mixing cups to weigh and mix the silicone accurately
• Optionally pigment and tools such as a small brush

Want a large or highly detailed shape? Then choose pourable silicone rubber rather than silicone sealant from a tube. It fills the mould much more evenly and holds sharp details better.

Is silicone safe for ice cubes?

A fair question, because it is going into your drink. For ice cubes, always use a food-safe silicone. It is intended for contact with food and drink and, when used correctly, does not pass on any taste or odour to your ice. Silicone rubber contains no fluorine compounds of its own and therefore does not belong to the PFAS group. Nor does it contain BPA or plasticisers, as some plastics do.

What to look for in food-safe silicones:

• They cope well with cold and heat. The freezer is no problem, and most platinum silicones can withstand up to around 200 °C. The exact limit is given in the product's technical data sheet.
• Cured silicone is a stable material that does not react with acids in food or drinks.
• For food-safe silicones the manufacturer issues a declaration, usually based on the European regulation EC 1935/2004 and the BfR recommendation XV for silicones. Which declaration is available for each product can be found on the product page, or you can request it from us. For more background, see our article on food safety and silicone.

Pay close attention to this when choosing, because not every silicone rubber is food-safe.

Make your own silicone mould in 6 steps

This is how you make silicone moulds. Follow these six steps and you will soon have your own ice cube mould:

1. Prepare your object. Clean and dry it and place it in a tub that is slightly larger than the object itself.

2. Weigh out the silicone. Weigh the two components exactly according to the ratio on the packaging. Working accurately ensures a good result.

3. Mix gently. Stir the components together thoroughly but calmly, so that as few air bubbles as possible form.

4. Pour the silicone into the tub. Pour in a thin stream from a height, so air bubbles escape by themselves. Make sure the object is completely covered by the silicone.

5. Give it time to cure. Let the mould cure undisturbed and do not rush this. Pulling it out too early will ruin your mould.

6. Remove the object. Has the silicone fully cured? Carefully flex the mould open and take your object out. Your own ice cube mould is ready.

Tip: when designing your ice cubes, think about how you will get them out of the mould. A flat base, for example, makes pushing them out much easier. For rounded shapes it is best to make two half moulds and freeze the halves together afterwards. Avoid deep recesses or sharp edges in your object, because they make your ice cube break off more easily.

How long does the silicone need to cure?

That depends on the type of silicone you use. Most mould silicones cure in a few hours to a day, and the exact time is always on the packaging. Our tip: give it a little longer rather than too short. A well-cured mould lasts much longer.

The differences between a short and a long curing time are:

• A short curing time gives you a quick result and is therefore handy for small or simple moulds. The downside is that the working time is also short, so you need to mix and pour quickly and accurately.
• With a long curing time there is room to mix and pour calmly. Air bubbles can also escape more easily, which often gives a cleaner result. The downside is that you need more patience before you can use the mould.

How to make your ice mould last

With proper care, a home-made silicone ice mould can be used hundreds of times. Rinse it after use with lukewarm water and a mild washing-up liquid and let it dry thoroughly. Store the mould in a dry place out of direct sunlight. That way your mould stays supple and ready for the next batch of ice cubes.

More than just ice

The great thing about a home-made silicone mould: you can do much more with it than ice cubes. Try pouring chocolate, jelly, fondant, candles or even soap into it. Once you have used a mould for candles or soap, do not use it for food again. One mould, lots of possibilities.

Frequently asked questions

How do you make a silicone mould?

You weigh out two components of liquid silicone rubber, mix them gently, pour them over your object and let everything cure. Then you take the object out and are left with a reusable mould.

Work accurately when weighing the mixing ratio and pour in a thin stream. That prevents air bubbles and gives you a mould that captures every detail. Want to see how it works first? Then watch this instruction video.

Which silicone should you use for ice cubes?

Always a food-safe silicone suitable for contact with food and drink. A platinum-cure silicone for which the manufacturer issues a food contact declaration is a good choice. It does not give off any taste or odour and stays supple in the freezer, so the ice cubes come out easily.

Can I also make chocolate in the same mould?

Yes. A food-safe silicone mould is perfectly suitable for chocolate, jelly and other treats. Silicone copes well with temperature differences, so the same mould goes from the freezer to melted chocolate without any problems. Do clean and dry the mould thoroughly in between, so the taste and details are preserved.

How long does a home-made ice mould last?

With proper care a silicone mould lasts for years. Rinse it after use and store it dry. Also avoid sharp objects and direct sunlight, so the material stays supple. That way you can get hundreds of pours out of one home-made mould.

Ready to get started? Above you can read everything you need to make your own silicone ice cube mould. Stuck? We are happy to think along with you, so feel free to ask us for advice. At Siliconesandmore.com you will find all the food-safe silicones and tools you need. Advice on the method and the choice of products comes free of charge.