Ask Nina Rose – What is Spherification?Posted: March 15, 2013
It’s Molecular March here at Fante’s! This week we’ve asked Nina Rose to give a little background on Spherification.
Aside from foams, one of the most popular and well-known textures used in molecular gastronomy and modernist cuisine are spheres.
To be more specific, a sphere comprised of a thin, jellied outer membrane with a liquid center that pops in your mouth when eaten. Sometimes these spheres can be called different names depending on their size and shape, from tiny “caviar” or “pearls” to large “ravioli” or “eggs.”
The method of creating these forms is called spherification (or reverse spherification, but I’ll get to that later).
So what is spherification?
Basic spherification is when you take your liquid ingredient (juice, broth, etc), mix it with sodium alginate (a gelling agent derived from algae) and drop that mixture into a bath of purified water and calcium salts (calcium lactate and calcium chloride are commonly used).
When the sodium alginate mixture comes in contact with the calcium bath, the reaction between the two additives causes a flexible gelled outer coating to form, while leaving the center of the droplet in it’s liquid state. The spheres are then removed from the calcium bath and “rinsed” in a bath of purified water and served immediately.
Spheres made using this basic technique must be eaten right away, because they will continue to gel down to the center, leaving a firm jelly ball without the explosion! This method does result in a very thin membrane (when eaten immediately), which many find pleasing because less pressure is use to create that fun pop in your mouth. There are many recipes for smaller spheres that call for basic spherification because the spheres won’t stick to each other and can be piled up to resemble a lovely heap of caviar!
Reverse spherification is another way of making these fun molecular treats. This time, the liquid ingredient is mixed with the calcium salt and dropped into a bath of purified water and sodium alginate, and again rinsed in purified water.
Although basic and reverse spherification both result in a gelled outer membrane and liquid center, there are a few characteristics that differ between the two.
Where in basic spherification the spheres must be eaten immediately, in reverse spherification the gelling reaction stops as soon as they are lifted from their bath, leaving a stable sphere that won’t turn into jelly throughout the entire form. This allows you to make them in advanced, where prep time may be an issue.
Another benefit to reverse spherification is that it is less sensitive to acidic pH levels, alcohol and calcium in the ingredients used, where you may run into problems achieving perfect results when using the basic method.
Many larger spheres are made using the reverse method in conjunction with other additives like Xanthan Gum, which helps large forms keep their shape without bursting open at the slightest touch. You may even find it easy to freeze your calcium mixture in a silicone dome mold, pop them out and let them thaw in the sodium alginate bath to create that perfect round form which can be challenging with oval-shaped spoons.
It can be very helpful to have a precision scale when working with these ingredients due to their potency in small amounts, but companies like Molecule-R and Biozoon have formulated their products for ease of use in home kitchens. Molecule-R provides small portion packs of the raw ingredients to just tear open and use, while Biozoon created an additive blend with maltodextrin (derived from potato starch) that is measured out with dosing spoons (allowing the user to work by volume instead of weight).
My favorite tool for making those perfect little caviar spheres is the 96-Port Caviar Maker, which allows you to drop 96 spheres in less than 10 seconds, as opposed to using individual pipettes and making them one at a time.
Simply pour your mixture into the tray, pull the liquid up into the syringe and press down the plunger of the syringe, holding the ports on the box over the surface of the bath to dispense. To make large spheres, pour your mixture into a spoon then gently submerge into the bath. Carefully flip the sphere a few times while it’s submerged — this will help keep the shape round and allow the bath to create an even gelling around the entire form.
Although spherification techniques aren’t commonly used in most home kitchens, the tools and additives are becoming much more readily available in specialty stores and online, and even shown on TV. So if you’re feeling adventurous, and have always wanted to try a little science in the kitchen, make some spheres!