Spherification
The art of creating an artificial shell around a flavorful, liquid substance is called Spherification, and it essentially involves encapsulating liquids in a sphere – in Danish called sfære.
A thin membrane is thus formed around the liquid. This membrane serves to keep the liquid inside, and when the shell is broken, the flavorful liquid will flow out. Within this discipline, countless types of liquids can be used, and the technique truly opens up the possibility of creating different and surprising taste experiences. The technique can be used for both large and small spheres, but can also be used to create tiny “caviar eggs” filled with flavor that almost explode in the mouth when bitten into.
There are two different ways to perform spherification, namely direct spherification and reverse spherification.
There are advantages and disadvantages to both methods, so which one is used depends entirely on the desired end product.
Read the instructions for the two methods below:
See e.g. articles/recipes within molecular gastronomy here.
Direct spherification (direct spherification)
This method is the most commonly used spherification method.
Advantages:
• The membrane/shell takes on the flavor of the content.
• The sphere will not merge with the other spheres in the bath.
Disadvantages:
• Technically more difficult to achieve perfect spheres – the method requires practice!
You will need:
- Sodium-alginate
- Calcium-lactate
- Immersion blender
- Demineralized water/water without lime
- Measuring spoon
- 3 bowls
- Optional: molecular skimmer or slotted spoon
- Flavored liquid
The alginate reacts with the calcium and forms a gel when it comes into contact with it. Therefore, it is important not to make spheres from calcium-rich liquids such as milk. This is also why we use demineralized water – or other water without lime – as tap water in Denmark contains too much calcium.
Follow this guide to direct spherification:
1) The flavored liquid
The flavored liquid must not contain too much calcium. Additionally, the pH value must be above 3.6 for the alginate to work properly. Adjust the pH value before adding the alginate to acidic liquids.
Pour the liquid into a bowl and add the alginate.
You need 1 – 2% alginate of the flavored liquid. That means if, for example, you have 100 grams of strawberry-flavored liquid, you need 1-2 grams of alginate.
Use the immersion blender to mix the alginate into the liquid. Then let it sit for at least 30 minutes in the refrigerator. This is done to remove air bubbles.
2) The calcium bath
Pour water into a bowl (here, the lime content in the water doesn’t matter, so just use tap water).
Add the calcium-lactate to the water. You need 1% calcium-lactate of the water, which means about 10 grams per liter of water.
Stir the water until the calcium-lactate is completely dissolved.
3 – Create a sphere
When the liquid has rested for at least 30 minutes in the refrigerator and the air bubbles have disappeared, take it out.
Find a measuring spoon in the size you want the sphere to be.
Take a spoonful of the liquid and hold it over the calcium bath.
When the spoon is just above the surface, pour the liquid into the bath. A membrane will form around the liquid, and it will sink to the bottom. If it doesn’t sink, it can be helped along by pouring a little water from the bath over it.
It takes some practice to find the right distance from the spoon to the bath as well as the correct pouring speed and technique. Remember, practice makes perfect!
Let the sphere sit in the bath for a few minutes before removing it.
Instead of a measuring spoon, you can also use a syringe/pipette to make small caviar eggs with a liquid center. The method you should use is the same.
4 – Washing
Fill a bowl with tap water.
After a few minutes, remove the sphere from the water. Use your molecular skimmer/slotted spoon for this purpose.
Move the sphere to the bowl with water. Stir to wash off the calcium water.
5 – Serving
Serve immediately after washing.
One of the disadvantages of direct spherification can be that the process doesn’t stop after washing. It’s the alginate that becomes a gel, so the gelling process will continue until the sphere turns into a gel. Therefore, there is a risk that the finished result will be very stiff. Serve before this happens.
Reverse spherification (reverse spherification)
This is the easiest method.
Advantages:
• Easy to work with – the best method for beginners.
• Perfect spheres every time.
• The gelling process stops upon washing. The sphere therefore never becomes a completely stiff gel.
Disadvantages:
• The spheres easily merge with the other spheres in the bath if they touch – the method requires practice.
• There is no flavor in the membrane other than alginate.
You will need:
• Sodium-alginate
• Calcium-lactate
• Immersion blender
• Demineralized water/water without lime
• Measuring spoon / Syringe
• 3 bowls
• Optional: molecular skimmer/slotted spoon
• Semi-sphere silicone mold
• Flavored liquid
The alginate forms a gel when it comes into contact with calcium. Therefore, you would normally not be able to use calcium-containing liquids such as milk to form spheres. But because we use reverse spherification here and thereby add calcium-lactate to the liquid, it is possible in this case to use a product containing lime.
Follow this guide to reverse spherification.
1) The flavored liquid
Pour the flavored liquid into a bowl and add 1% calcium-lactate. You need 1 gram of calcium-lactate per 100 grams of liquid.
Stir until the calcium-lactate is completely dissolved.
2) In the freezer
Use a semi-sphere silicone mold in the size you want your finished spheres to be.
Pour the liquid into the mold and place it in the freezer. It should stay until the spheres are completely frozen.
3) The alginate bath
Pour demineralized water/water without lime into a bowl. Here, you need to use lime-free water, so you cannot use tap water.
Add 1% alginate to the water – this means adding 10 grams of Sodium-alginate to 1 liter of water.
Blend the mixture with an immersion blender. This ensures that all the alginate is dissolved in the liquid.
Let the bath sit until the air bubbles disappear.
4) Create the sphere
When the spheres in the mold are frozen and the alginate bath is air-bubble-free, you can continue the process.
Take the alginate bath out of the refrigerator and the semi-sphere mold out of the freezer.
Put each frozen sphere into the alginate bath and let it sit for a few minutes. Be aware that the warmer the alginate bath is, the faster the thawing process will be.
Stir the alginate bath so the spheres do not touch each other. If they do, they will merge, which is important to avoid.
5) Washing
Fill a bowl with demineralized water/water without lime.
After a few minutes, remove the spheres with a slotted spoon / molecular skimmer and transfer them to the bowl with the lime-free water.
Stir to wash off the alginate. The gelling process then stops immediately.
6) Serving or storage
The spheres can be served immediately after the final bath.
Since the gelling process using this method stops at washing, the sphere will never become solid – i.e., firm all the way through and without the liquid center. It can therefore also be stored for later use.
The sphere can be stored in a container with olive oil. If stored in water, the water will dilute the liquid inside the sphere, and it will seep through the membrane, resulting in the sphere being destroyed.
The easiest way to start experimenting with molecular gastronomy at home is to purchase a molecular gastronomy starter kit or molecular gastronomy spherification set. Both can be purchased here.
See e.g. articles/recipes within molecular gastronomy here.