Sodium alginate (C6H9NaO7) is a chemical that’s extracted from brown seaweed to be used in many different kinds of foods. For example, it acts as a stabilizer for ice cream and yoghurt, and is a thickener for salad dressings and canned products. When it’s in the presence of calcium it forms a gel that requires no heat to take shape!
Calcium Chloride (CaCl) is a salt that acts as a preserving agent in some foods. It’s what makes pickles and other similar foods taste salty without adding actual table salt. It can also be used to tenderize meat and make fruits and vegetables more firm. This chemical assists in creating a gel membrane around liquid.
Because the membrane around a sphere is very thin, it can’t hold as much water as a plastic water bottle could. Instead, when using the spheres to replace a water bottle, you’d need to have multiple spheres ready to drink. One company in the UK has started marketing their own version of edible water “bottles” called the Ooho. There are actually two layers of gel in the Ooho before you reach the water inside. The outermost layer is meant to be peeled off, like a banana peel, to protect the actual water from contamination.
Make Your Own Edible Water Bottle
To make your own water sphere, you’ll need just a few ingredients, which are easy to find online. We’ll use calcium lactate instead of calcium chloride in this activity, because we don’t want our water to taste salty!
What you need:
- 1 gram (0.04 ounces) of sodium alginate
- 5 grams (0.18 ounces) of calcium lactate
- Three mixing bowls
- Hand mixer
- Wooden spoon
- Slotted spoon
- A spoon with an exaggerated curve
Step 2: In another bowl with 4 cups of water, add in the calcium lactate and stir well using the wooden spoon. Make sure everything is dissolved.
Step 3: Take your curved spoon and scoop up the sodium alginate solution and gently place it into the calcium lactate bath. It will start to form a sphere immediately. Repeat this step as many times as you like, just make sure not to add too many to prevent the bowl from getting crowded.
Step 4: Using the wooden spoon, stir the bath with the spheres very gently for about three minutes to help the gel membrane fully form.
Step 5: Use the slotted spoon to scoop up the water spheres and place them in the last bowl, filled with regular water. This will stop the reaction and prevent the gel from getting too thick.
Now you can pop your water “bottles” into your mouth for a nice drink of water! The gel is completely edible, but if you don’t like the texture you can throw it in the compost and it will decompose just like the skin of a fruit.
Baguley, Richard. “Appliance Science Experiments: Creating edible water spheres”. CNET - July 2015. Accessed April 21, 2017.
Lastras, Javier. “Spherification of Green Tea”. Released into the public domain under the Creative Commons Attribution 2.0 Generic license. Uploaded on 4/22/17 from wikimedia.org
Arnold, Karen. “Salt in the Hand”. Released into the public domain. Uploaded on 4/22/17 from publicdomainpictures.net
Rondeau, Charles. “Plastic Bottles”. Released into the public domain. Uploaded on 4/22/17 from publicdomainpictures.net
Hodan, George. “Water Drops on a Spoon”. Released into the public domain. Uploaded on 4/22/17 from publicdomainpictures.net