Gel and jelly: which gelling agents should you use?
Making a jelly might seem simple but what actually happens when you make a gel or jelly? And which gelling agents do you use for which jelly or gel? In this blog we give an overview of the most commonly used gelling agents in the kitchen and how to use them.
When you zoom in closely on a gelatin gel, you can see that the moisture has been captured by protein spirals. The tighter the spirals are interwoven, the stronger the gel formation and stability. Gels can also be formed with carbohydrates such as agar agar, gellan, and alginate. These products contain molecule chains that encapsulate and retain the moisture. The advantage of these gelling agents is that they can be processed at higher temperatures in contrast to gelatin.
Illustration: Harold McGee, On Food and Cooking, p. 602)
Gelatin: the all-time classic
Gelatin forms a soft gel that 'melts' in your mouth and gives a pleasant mouthfeel. Gelatin sets at 18°C. Anything above this temperature and the gelatinising properties start to decrease. After heating, allow the liquid to cool down gently to room temperature before leaving it to set in the refrigerator. By allowing it to cool down in this way, the network of protein spirals becomes stronger than when the process is forced by immediately placing it in the refrigerator or blast chiller. Gelatin is often used in desserts, for example in a bavaroise or foam from the siphon, but also in savoury dishes such as an aspic. We use two types of gelatin in the kitchen:
- Gelatin leaves: can absorb ten times their actual weight in moisture. It is therefore important for the gelatin to be soaked in plenty of cold water at a temperature of 7°C. By first soaking in cold water, the gelatin dissolves more easily in a warm liquid.
- Powdered gelatin: is often used to make sweets, as it is more resistant to heat than gelatin leaves. Powdered gelatin needs to be dissolved in the liquid you eventually use. Stir the gelatin into the liquid at room temperature and leave to soak for fifteen minutes. Then heat to a maximum of 50°C to activate.
The gelling power of gelatin depends on the other ingredients used.
- Salt disrupts the gelling power, as it disrupts the gelatin molecules.
- Sugar strengthens the gelling power because it retains moisture.
- Milk makes a gel stronger.
- Alcohol strengthens the gel 30-50% of the total gel mixture. A higher amount will cause the gelatin to drop.
- A liquid with a high pH value reduces the gelling power. Examples of these include acidic products such as vinegar and fruit juices.
A gelling agent that is extracted from algae and can be used both hot and cold. An agar gel can be used up to 80°C, only above this temperature will the gelling power decrease. To make an agar gel, mix the agar agar with a cold liquid and bring to the boil while stirring. Pour the gel into a mould and place in the refrigerator to set. An agar gel has a firm bite and can give a granular mouthfeel because it does not melt in the mouth. An agar jelly is therefore often turned into a gel in the blender. Examples of agar gels include this raspberry gel or a warm jelly of red cabbage.
Gellan is a secretion of a bacterium. This product is used to make a clear gel from acidic or salty liquids.
Pectin is a gelling agent made of fruit that forms a solid gel that is often used in combination with citric acid. The acid creates a more stable and firm gel. Pectin occurs naturally in all kinds of fruits and is therefore often used in the making of marmalades and confiture. Due to its strong gelling power, this product is also suitable for making sweets such as pâte de fruits which, as the name indicates, is also made with fruit.
Alginate is a gelling agent that works in combination with calcium and can therefore be used for gelling dairy products. In the kitchen, alginate is often used with a two-part technique developed by ElBulli that consists of the making of a liquid containing the alginate and a calcium solution. When the alginate liquid is introduced into the calcium solution, a reaction occurs which causes the liquid to gel. Once out of the solution, the gelling process will continue to work slowly.
Is a composition of locust bean gum, kappa carrageenan, and maltodextrin. Dissolve in a cold liquid and heat to above 65°C while stirring. Then pour it into a mould and allow to set. The gel is slightly elastic and has a pleasant mouthfeel. Use vegetal for both hot and cold preparations such as duck orbs with hoisin jelly or salmon in aromas of liquorice.
A combination of the above agents
It is also possible to form a gel with a combination of the different gelling agents. For example, agar agar is used in combination with gelatin to make a soft gel that lasts longer in a warm kitchen. The recipe for the sweet potato and peanut panna cotta uses a vegetal and agar agar combination for firmness with a pleasant mouthfeel.
On Gastronomixs you will find the cooking technique ‘making jelly’: definitely worth a look! In addition, you will find many different components that use a gelling agent. Not a member but want to view the components? Sign up now and try out Gastronomixs for free for two weeks!