Candied peel – why it works

Seville oranges

Whenever I make marmalade, the huge piles of wasted peel get me down. While I like the taste of orange peel, i dont like my marmalade to be jam packed with it, so I tend to include only some of the peel in the preserve. But those shiny, bright orange skins disappearing into the food waste bin is such a sad sight. Its only the exhaustion induced by the particularly time consuming method of marmalade production that leads me to discard these skins. Because instead, I could be making candied peel – and this is what I did this time.

But what is it that turns orange peel into candied peel successfully? All the recipes say different things, even though it’s a very simple recipe. The idea is to remove some of the bitterness that makes orange peel unpleasant to eat raw, soften it so you can bite through easily, and then steep in sugar syrup to sweeten and preserve it, without causing the sugar to recrystallise.

Candied orange peel

The problem is that hardly any of the recipes explain why they have the steps they do. Not understanding what’s going on really annoys me. If I don’t know the purpose of each step, then it’s much harder for me to work out when each stage is done, or to spot if something has gone wrong.

And this is a baking-type recipe – it should be precise – but when all the recipes disagree slightly, how do you know which one to follow?

In the case of the candied peel, the basic steps are:
1. Remove the peel, either by scoring the entire peel, or by peeling just the zest with a peeler (if you do that, there generally isn’t a requirement to blanch it).
2. Blanch the peel – in anything from 1–5 changes of water. (Sometimes, boil the peel until tender) as well.
3. Immerse in sugar and water, anything from 1:1 ratio to 2 parts sugar to 1 part water. This might also include some corn syrup, or some cream of tartar. Boil for anything from 30 minutes to 2 hours.
4. Put out on a rack to drain. Roll in sugar straight away or leave out to dry for a day or several days.

That’s a lot of variation for very few steps of instruction. Obviously, you’re dealing with two big uncertainties: a natural product, the orange, that can be sweet or bitter, thick-skinned or thin skinned; there’s also another uncertainty that is acknowledged in recipes much less often: your individual palate. Relatively few recipe writers encourage you to taste as you go and then adjust suit what you would prefer. Do you quite like the bitter tang of orange peel or do you have a sweeter tooth? Are you planning to use this peel in recipes where the sour contrast is going to be appreciated, or would you like to eat these with chocolate where you want things a bit sweeter?

The first part, the blanching is there primarily to remove the bitterness from the pith – or at least moderate it. Harold McGee explains:

“The outer epidermis contains the aromatic oil glands while the spongy, pectin-rich
albedo usually contains protective bitter phenolic substances. Both the oil with its
terpenes and the antioxidant phenolics are valuable phytochemicals. The bitters are
water-soluble, while the oils are not. Cooks can therefore leach the peel repeatedly
with hot (rapid) or cold (slow) water to remove the bitter compounds, then gently
cook the peel if still necessary to soften the albedo, and finally infuse it with a
concentrated sugar syrup. Through all the processing, the water-insoluble oils stay
largely in the rind.” – from ‘On Food and Cooking’

So blanching the orange peel makes it edible by removing the bitter compounds and softening the pectin. This means you should be able to taste it, and test the softness, to determine how many times you want to blanch the peel.

When you infuse it with sugar syrup to preserve it, you are trying to reach a certain concentration of sugar, and this is most easily measured with the boiling temperature of the syrup. As you boil a sugar syrup, the temperature increases as the amount of water decreases, and the sugar gets more concentrated – this is essentially what a sugar thermometer is measuring. At a boiling point of 230 degrees F / 110C you get to about 80% concentration of sugar. This is a good level for candied fruit. If you stop at a lower level, there is a risk of crystallisation, as well as a risk that the peels will remain too sticky and not keep well. This also means that it doesn’t matter too much what ratio of sugar to water you start out with – except that a weaker solution will take longer to reach the right concentration, meaning that the peel will be submerged for longer, and this can help make sure that the syrup penetrates all the way through properly, especially with thick pieces of peel.

Candied orange peel
Traditional candying processes for whole fruits – for cherries, tangerines, melon in places like France – require the fruit to be cooked in increasingly concentrated syrups over many days. This allows the sugar to penetrate into the thick fruit and ensures that the water is displaced.

Adding cream of tartar (an acid) along with the sugar helps to prevent crystallisation of the sugar in the final peels. The acid helps encourage the sucrose in the granulated sugar to break down into glucose and fructose, its two smaller units. These get in the way of the sucrose reforming nice neat sugar crystals. Adding corn syrup does a similar job – it already has glucose and fructose in it, so they also help interfere with crystallisation.

The peel should cook for a good long time in the syrup – 45 minutes to 2 hours is the general guidance. Slow is good, to make sure the peel is well infused. Then remove the peel from the syrup and spread onto a cooling rack to dry a little, and become tacky rather than sticky to the touch. Then you can roll in sugar, or dip in chocolate, as you prefer.


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4 comments on “Candied peel – why it works

  1. Shara says:

    This is INCREDIBLY helpful. Thank you! 🙂

  2. David says:

    The Glace’ Fruit Pro’s in France, Italy, and Spain use a series of sugar solutions, going from wet to dry, increasing in sugar strength and hence boiling point to remove the fruit’s water and replace it with sugar. The aromatic notes of each fruit are very volatile and easily boiled off (this is called steam distillation and used to capture these essential oils for perfumery and also important for distilled spirits like Eau de Vie) so this process conserves the essential oils while allowing the water to be replaced in a stepwise fashion. Note that the fruit is NOT boiled in the sugar solution but stored in it possibly heated to speed up equilibrium, so as to not destroy the volatile fruit essences with excessive heat. This can take weeks or months for larger whole fruits. The initial boiling is different for each type of fruit, some are so soft as to not tolerate long heating before going to mush in the pot. Glace fruit may also use a less ripe fruit to keep it from falling apart before it is preserved.

    Citrus peels can handle a more extended boil as the heat converts insoluble fiber in the pith to transparent soluble fruit pectins and bitterness is reduced as the pith degrades.

    Glucose and Fructose are half the size of sucrose, so you get almost twice the drying power per pound of sugar when using the simple sugars to preserve your fruit. Think Caro syrup instead of table sugar unless HFCS is out in your house.

    from Wikipedia’s Candied Fruits page:
    Recipes vary from region to region, but the general principle is to boil the fruit, steep it in increasingly strong sugar solutions for a number of weeks, and then dry off any remaining water.[4]

  3. Olaf Unsoeld says:

    I was too lazy to grab my McGee . . . and the variations in sugar to water ratios were disconcerting, as I knew I could end up with either hard or sticky peels. The boiling temp required is just the info I needed . . . as is the issue with crystallization. Many thanks for explaining all the important variables so succinctly.

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