Royal Icing: How to Store It and How Long It Lasts

Royal icing made with raw egg whites keeps in the fridge for up to 3 days at most, while icing made with dried egg white keeps for up to 2 weeks; in the freezer that's 1 month versus 2–3 months respectively. The egg white is what makes the difference: raw versus heat-treated (dried or pasteurised). Here are rough guidelines for icing stored in a well-sealed container:

• Made with raw egg whites: at room temperature only for as long as you're actively decorating, 2 hours max at room temperature; in the fridge, 3 days max; in the freezer, up to 1 month.

• Made with pasteurised liquid egg white: in the fridge, about 1 week.

• Made with dried egg white or a ready-made mix: at room temperature, about 1 week; in the fridge, up to 2 weeks; in the freezer, 2–3 months.

• Dried onto cookies: lasts as long as the cookies themselves, as long as it's fully dried and stored somewhere dry.

Professional decorators often quote longer times for dried-egg-white icing — even a month in the fridge. But when I'm baking at home, I stick to the shorter end of the range. Either way, the icing only has that perfect piping consistency for a few days before it gets harder to work with.

What determines how long royal icing lasts is the egg white, not the sugar: raw egg white can carry salmonella, while dried egg white is heat-treated. Icing sugar itself doesn't spoil, since bacteria struggle to grow in such a sugary environment. But until the icing dries out, it still holds enough moisture for microbes from raw egg white to multiply. That's why icing made with raw egg whites behaves like any fresh egg product: it belongs in the fridge and shouldn't be left sitting out for long.

Dried egg white and pasteurised liquid egg white have both been heat-treated, so this risk is almost entirely removed. Icing made from them is more stable and works well if you're decorating over several days in a row, or if the cookies will be eaten by young children or pregnant women. You'll find the ratios and method in the article Royal Icing: Ratios, Consistency and Colouring.

Store royal icing in the fridge in a clean, sealed container with plastic film pressed directly onto the surface. Air is what does the most damage: within minutes a sugary crust forms on top, which then breaks down into hard lumps when stirred and clogs your piping tip. Here's how:

1. Transfer the icing into a clean, dry, grease-free container. Even a trace of fat will make the icing harder to whip and set.

2. Press plastic film directly onto the surface of the icing so there's no air trapped underneath.

3. Put the lid on the container and place it in the fridge.

4. Label it with the date and note what type of egg white it's made from. After three days, you won't remember.

Store coloured icing separately, sorted by colour. Bold shades, especially red and black, deepen further over time, so stored colour usually ends up a shade darker than it was when fresh.

Yes, royal icing can be frozen, and once thawed it works almost the same as fresh icing. This is especially handy for leftover coloured icing you'd otherwise have to throw away.

• Put the icing in a freezer bag, press out the air and seal it. You can also pipe it straight into a piping bag and then wrap that inside a freezer bag.

• Thaw it in the fridge overnight, never on a radiator or in the microwave.

• Once thawed, stir it smooth with a spatula (see below), since it will always separate slightly after freezing.

Freezing doesn't kill bacteria, it just stops them multiplying. So for icing made with raw egg whites, count the time before freezing and after thawing towards the total 3-day fridge limit.

Stir stored royal icing by hand with a spatula, working up from the bottom, until it's smooth again. It will almost always separate: a thick white layer stays on top while clear liquid settles at the bottom. That doesn't mean it's gone bad — it's just the water separating from the sugar.

• Stir slowly, until the icing is glossy and streak-free.

• Don't blitz it with a mixer on full speed. That will whip air bubbles into it, and those show up on the cookies as tiny craters.

• Check the consistency. If it's too thin, stir in a teaspoon of icing sugar. If it's too thick, add a few drops of water. For what the right consistency should look like for outlining versus flooding, see the article Royal Icing: Ratios, Consistency and Colouring.

If a crust has formed on the surface even under the plastic film, scoop it off with a spoon and don't stir it back in. The hard bits won't dissolve and will clog your piping tip.

Royal icing in a piping bag can be stored in the fridge overnight with the tip twisted shut or clipped, no need to empty the bag. Twist the tip of the bag or clip it shut, place the bag inside a resealable bag or container, and put it in the fridge. Cover any nozzle left attached with a damp piece of paper towel so the icing inside doesn't dry out.

If you're decorating for a whole afternoon, only take out the bag you're actually working with at any moment. Keep the rest covered and waiting. Icing made with raw egg whites shouldn't sit out of the fridge for more than 2 hours at room temperature. Before you start piping again, knead the bag gently in your hands to bring the icing back together.

Royal icing that's fully dried on a cookie lasts as long as the cookie underneath it does. Once the moisture is gone, what's left is a firm sugar crust that bacteria can't thrive in. But it does need to dry properly: thin outlines need 6–8 hours, while larger areas flooded with thick icing need 12–24 hours. Don't stack the cookies or seal them into a box before then.

• Let them dry in a single layer on a rack at room temperature, not in the fridge. Moisture condenses on the icing in the fridge and makes it sticky.

• After that, store them in layers separated by baking paper so the decorations don't crack or rub off.

• Decorated gingerbread cookies that are meant to soften need a bit of moisture, but the icing needs the opposite — dryness. For how to balance the two, see how to store gingerbread cookies so they soften.

For how long different kinds of cookies keep, see the overview how long Christmas cookies last by type. General rules for boxes, layering, and keeping different types separate are in the article how to store Christmas cookies so they stay crisp. For when to start baking and decorating, check the Christmas cookie baking calendar.

Cookies decorated with royal icing can be frozen, but you must thaw them in a closed box, otherwise moisture will condense on the icing. On cold cookies, moisture from the air settles as soon as they come out of the freezer, and underneath it the icing can smear or the colours can bleed. So only open the box once the cookies have reached room temperature. Only freeze cookies with icing that's fully dried, in one or two layers separated by baking paper. The full method is in the article how to freeze cookies and thaw them without them going soggy.

Royal icing holds best on gingerbread cookies with a smooth, flat surface that don't crack after baking. Both recipes below fit the bill, and thanks to the soft dough, they won't crack once decorated either. If what you're after is a simpler glaze straight on the cookies instead, continue with the article Gingerbread Cookie Glaze: Recipe, Consistency and Decorating.