Learn the science behind:
It’s squishy and bouncy. Sweet, but not extremely so and flavored delicately. And, even though it’s jelly-like, it doesn’t contain that typical jelly ingredient: gelatin. Instead, the secret behind the unique texture of a piece of pistachio Turkish delight is corn starch!
The one disadvantage? Unlike with many other types of candy, there’s no easy way to measure when your homemade pistachio Turkish delight is done. It needs a little bit of experience. Or some proper understanding of what it is you’re trying to do. Luckily, that’s exactly what we’ll discuss right here!
- Turkish delight challenge: Getting the consistency right
- Cooking sugars to drive off moisture
- Use starch to thicken Turkish delight
- Cooking to the right consistency
- Adding pistachios & color to Turkish delight
- Storing Turkish delight without sweating
Turkish delight challenge: Getting the consistency right
What sets Turkish delight apart from many other styles of candy is its texture. It is bouncy and soft. You can easily bite into it and it will melt away in your mouth quite easily. It’s not too dissimilar to a pectin gummy, or one made with gelatin, but isn’t exactly the same either.
In the case of Turkish delight, the secret behind this texture lies in the use of corn starch. Combined with sugar, it can create that unique bounce, but, it can be tricky to get just right. A good quality piece of Turkish delight should have a solids content of about 80%, the rest being water. Too much water will make the candy too soft and prone to stickiness. Not enough water and the candy will be tough and chewy. Whereas a thermometer can often tell whether a candy is done, that is not the case for Turkish Delight.
Turkish Delight has been made for centuries, indeed, originating in Turkey. Instead of the English name you might know it as Lokum or Loukoum.
Cooking sugars to drive off moisture
Like most types of candy, Turkish delight is made up of mostly sugar. And, as is the case for many other sugar confections, making Turkish delight involves making a sugar syrup. The main goal of making the sugar syrup is to dissolve sugar in water and get rid of the sugar crystals.
Once the sugar has dissolved, it’s a matter of boiling off enough water to get to that ideal Turkish Delight consistency. The more water evaporates, the firmer the final Turkish Delight will become. There are many ways to make Turkish Delight, but most involve two cooking steps in which moisture is driven off. First, a highly concentrated sugar syrup is made. Temperature is the perfect measure for moisture content (here’s why) of these syrups. The hotter the boiling syrup, the lower the water the water content.
Breaking down (some) sugars with acid
You can make pistachio Turkish Delight with just granulated, refined sugar as a sugar source. However, sugar is prone to crystallization and the final texture may not be soft enough. It is why many recipes call for adding some acid to the sugar syrup at either this step, or in the last cooking step. The acid will break down some of the sugar into invert sugar. Invert sugar isn’t as prone to crystallization and holds onto water just a little better. It softens the texture as a whole. But, adding too much acid can break down too much sugar resulting in a very sticky piece of Turkish Delight.
The most commonly used acids are tartaric and citric acid. But lemon juice, as well as vinegar can be used as well.
Honey increases stickiness risk & softness
Instead of adding and acid, or on top of adding it, you may also decide to use honey. Granulated sugar is made up of sucrose and once it’s broken down into invert sugar it consists of equal ratios of glucose and fructose. Honey barely contains any sucrose and naturally consists of mostly glucose and fructose. As such, it will naturally help to soften the texture.
However, don’t try to replace all the sugar with honey! Using just honey will make the Turkish Delight way to sticky and soft and it won’t hold together as well. It will also be more sensitive to humid environments, absorbing moisture from the air during storage.
Use starch to thicken Turkish delight
Key to making Turkish Delight is the addition of starch, in most cases corn starch. If you’d just cook a sugar solution to the required water content you’d likely end up with an soft piece of candy that can’t hold its shape. Corn starch helps firm up the candy and gives it that soft chewy consistency.
Corn starch thickens your pistachio Turkish Delight through a process called gelatinization. It contains little ‘packets’ of starch molecules. At room temperature, these starch molecules will first absorb water and spread out. Once you start heating a corn starch + water slurry, the starch will absorb more and more water, causing the starch particles to swell. At some point, they break, releasing all the individual starch molecules into the slurry. Starch molecules love water and they’ll each hold onto a lot of water. This is what causes the mixture to thicken. You use this exact same concept when making a water roux, bechamel sauce, or corn starch based ice cream.
Always mix corn starch with COLD water first!
Key to creating this nice thick paste is that the corn starch has a chance to spread throughout the water first, before swelling up. It is why it is key to always mix the corn starch with cold water first. This allows the starch packets to spread around, before starting to swell. Once they start swelling, they’ll block one another from reaching enough water.
Also keep in mind that the corn starch will absorb a lot of water. It is why it may feel like you’re mixing a lot of water with the starch. However, most of that will be absorbed. If you don’t add enough, you can inhibit the full gelatinization of the starch.
Mixing with icing sugar can prevent clumps
Some methods may call for mixing the corn starch with some icing sugar before mixing it in with the cold water. Again, this can help prevent clumping. The sugar molecules will sit in between the starch particles, keeping them separated. Since sugar dissolves very well in water, it won’t interfere.
Adding acid helps gelatinization
For a good high quality piece of Turkish delight it is crucial that the starch within has completely gelatinized. This ensures that it can hold onto a lot of water, making it squishy and juicy, without losing that water during shelf life. You will find that this step as well maky call for the addition of a little bit of acid. This can help that gelatinization process to occur faster and more efficiently.
Vegan Turkish Delight
Seeing as how you only need corn starch and sugar to thicken Turkish Delight, it can be vegan. There’s no need for gelatin, an animal-based product. Honey can be used, but it’s not a requirement and you can simply replace it with regular sugar.
Cooking to the right consistency
Again, there are several ways to make pistachio Turkish Delight. The recipe we share at the bottom is just one of them. Nevertheless, all recipes will at some point make a sugar syrup and a corn starch slurry. How and when exactly these are added together though differs.
In the method below we cook the sugar syrup to quite a high temperature. This ensures a lot of water has already evaporated. This will lessen the time for the final cooking step. Also, we pre-cook the starch slurry. This ensures the starch has already had a chance to gelatinize. As a result, when adding the hot sugar syrup to the corn starch, there’s not as much of a risk for clumps!
No matter how you add the two parts together, the mixture as a whole will need to be cooked for quite some time. In industrial conditions, this process can take hours. Two main processes take place during this step. First of, more water is evaporated. To get to that final desired consistency, the right amount of water at the end is key. Secondly, the starch continues to hydrate and interact with the water. This won’t take as long, but does continue to happen.
Why a thermometer doesn’t work
Normally, when making candy, the boiling point of a sugar mix will tell you whether you’ve evaporated enough water. However, in the case of Turkish Delight this won’t work. One major reason for this is that thermometers get notoriously unreliable. The thick corn starchy paste surrounds the probe, making it hard to get an accurate read.
In manufacturing, an alternative solution is using a refractometer. This is a simple measuring device that can tell you whether the water content of the mix is low enough.
If you don’t have a refractometer, you’ll be able to judge whether it’s ready by quickly cooling down part of the mixture. If it has the right consistency
Adding pistachios & color to Turkish delight
Last but not least, the Turkish Delight needs to be finished with some additional color and flavor. Without it, it would just be sugar and corn starch, quite a neutral, but sweet, flavor. Traditionally, rose water is commonly used as well as lemon flavoring, but the options are endless. Here, we decided to go for a green pistachio Turkish delight version, with some pandan flavoring!
Once the starch + sugar mixture has finished cooking it will start to thicken upon cooling. It’s why it’s important to mix in any flavors, colors, and other ingredients right at the end of cooking.
Color your pistachio Turkish delight green with coloring
Most pistachio Turkish Delight isn’t green in color. Instead, it’s brown. Even though pistachios have a green hue to them, that green color breaks down easily and only makes up a very small portion of the pistachios. Roasting pistachios increases that effect, making them even browner in color. However, roasting also adds a lot of great flavor, and makes it easier to chop them up, so is definite a worthwhile additional step. That said, if you’re looking for a green color to your pistachio Turkish delight, you will need to add that color.
Storing Turkish delight without sweating
The Turkish delight ‘jelly’ is very prone to sticking and becoming sweaty. This is caused by the large amount of sugar it contains. The sugar pulls moisture out of the air, onto the Turkish delight. It is key that Turkish delight gets enough time to cool down and dry before you cut it. This helps to ensure that the piece of candy is firm enough and that helps against it turning sweaty.
It is why pieces of Turkish delight are always heavily coated in either pure icing sugar or a mix of icing sugar and corn starch. Corn starch can take up quite a lot of moisture, without getting sticky itself (as can be seen in moisture sorption isotherms). By drying out the sugary outside, it can form a thin crust around the Turkish delight, protecting it from its surroundings.
Do not stack Turkish delight
Since Turkish delight is quite a vulnerable piece of candy, it is best not to stack pieces of Turkish delight on top of each other. The moisture will simply travel from one piece to the other, driven by a gradient in water activity. This can cause them to stick to one another quite easily.
Batu, Ali & Kirmaci, Bilal. (2009). Production of Turkish delight (lokum). Food Research International – FOOD RES INT. 42. 1-7. 10.1016/j.foodres.2008.08.007., link
Lees, R.. Sugar Confectionery and Chocolate Manufacture. Germany: Springer US, 2012., section 12.6: Turkish Delight, link