When it comes to understanding hydrocolloids, there is a laundry list of new terms you have to learn. It can also feel like a barrier for entry with attempting to use these ingredients. So let’s go over the top 10 terms you should know when you start using hydrocolloids.
“ What does some of these terms mean?”
Cold soluble: This is a term that is used to describe an ingredient that can be mixed with cold water; it does not require heating. You may also see that some ingredients are “partially called soluble“. This means that the ingredient will most likely thicken a liquid when cold and create a gel once it is heated to a specific temperature.
Hot soluble: this term is used to describe an ingredient that must be heated in order to be activated. A great way to understand this is a cornstarch slurry. Starch slurry will remain fluid at room temperature. And overtime it will even separate partially from the water. But when the cornstarch slurry is heated then its thickening properties are activated. This is true for most hydrocolloids that create gels.
Shear: Shear or high shear are terms that are used to describe blending at high speeds. Most ingredients that are hydrocolloids will require a high speed blend to ensure that they are evenly distributed into the liquid. Without shearing many of these ingredients will clump when they come in contact with water.
Hydration temperature: Hydration temperature is the temperature in which ingredients will solubilize. Each ingredient will stabilize at different temperatures. Some thickeners require room temperature others prefer cold water. Most gelling agents will need to be heated to 180°F to solubilize.
Gelling (setting) temperature: A gelling or setting temp is the temperature at which the solubilized ingredient will form a gel. This is most commonly a colder temperature than the hydration temp. In special cases such as methylcellulose the temperature at which a gels is higher than the temp at which it becomes soluble.
Melting temperature: The melting temperature is the temperature at which a gel that has already been formed will melt. This all depends on the ingredient. Some gels will melt at a higher temperature than the gelling temperature and others will melt at the same temperature as the gelling.
Thermo-irreversible: Thermo-irreversible is a term used to describe a gel that will not melt. If the gel does not have a melting temperature then it is thermo-irreversible.
Thermo-reversible: Thermo-reversible gels are gels that will melt once they have set. If a gel has a melting temperature listed then it is a thermo-reversible gel.
pH tolerance: commonly you will find a pH tolerance on ingredients. This is a threshold where the ingredient will work and not work. Anything below the pH number that is given ingredients will most likely not gel or thicken. The high acidity/low pH renters the ingredient inactive. Certain ingredients can be activated by a high pH. If this is the case it will say “this ingredient creates a gel at 9.0 pH”.
Syneresis: This term can also be referred to as weeping. This means that overtime the gel will constrict and force the water out. It will give the appearance of water droplets on the outside of the gel. This is why the term weeping is commonly used.
Feel free to use this glossary as a quick guide to better understand the terms used with most functional ingredients. And until next time keep cooking!