Two weeks ago we dropped an article that covered direct spherification. We covered the ingredients needed for spherification and some of the tools. But there are some limitations to direct spherification. With direct spherification you must be mindful of the acidity of your spheres. If you wanted the spheres to add an acidic pop to a dish, direct spherification will only allow you to have spheres at 4ph or higher. Some foods that hang around 4ph are things like black coffee, buttermilk, and beer. So if you want something more acidic than that, you will need to attempt reverse spherification. The second biggest downfall of direct spherification is that the spheres will solidify over time. Thankfully reverse spherification allows you to make spheres that will not set and can be nice and acidic for your dish. But you’re probably wondering…
“What’s the deal with reverse spherification?”
If you haven’t read our article about direct spherification, we suggest that as a quick primer for the spherification process. Either way, here’s a quick recap of how spherification works. When a sodium alginate solution comes in contact with calcium it creates a gel. Because of this we are able to encapsulate liquids in a thin gel and create spheres.
Reverse spherification works just as it sounds. You will reverse the process. Rather than adding calcium to the setting bath it will now be added to the flavorful liquid. The calcium that is used in direct spherification is calcium chloride. Calcium chloride has a bitter flavor and should not be used in reverse spherification. Calcium lactate and calcium lactate gluconate are two types of calcium that are flavorless and will not alter the flavor of your liquid. They should be added to the flavor full liquid in a ratio of 1% to the total weight of the liquid. The sodium alginate should be added to the water in your setting bath. Using tap water for this is not a good idea as most tap water contains calcium. We strongly suggest using distilled water to prevent any headaches. As the spheres are added to the setting bath the calcium within the flavorful liquid will begin to gel the sodium alginate around it. This means that the sphere will never solidify. That’s about it for the basics of reverse spherification. It’s a much more forgiving and inviting way to make spheres. But there are some tricks of the trade you should know before making your first spheres.
So class… what do we know about sodium alginate? It creates a gel, yes. It doesn’t play well in acidic environments, yes. What else? It thickens, Bingo! Sodium alginate thickens the liquid it hydrates in. When a thin liquid is added to a more viscous liquid it tends to sit on top. This can make it very difficult to make spheres. But alas there is a couple of quick fixes for this issue. Adding xanthan gum in a ratio of 0.1% to the total weight of the flavorful liquid will thicken it enough that it will sink in the setting bath. Making ravioli sized spheres are ideal for this method. Unfortunately making caviar sized pearls is extremely difficult if not impossible to do on a small scale. Reverse spheres tend to bond together if they are too close in a setting bath. Attempting to set dozens if not hundreds of caviar sized pearls at once is extremely difficult. That is if you can even get them to sink into the setting bath.
There is one more method that can help greatly when spherifying thinner liquids in a viscous sodium alginate setting bath. Frozen reverse spherification is probably the easiest form of spherification. As long as you get the setting bath right and don’t forget to add calcium to your flavorful liquid it will work. It works by freezing your flavorful liquid into a mold and plunking them into the setting bath. As they thaw, they will begin to form a gel. This requires no extra thickener as the freezing keeps them in the correct shape.
When removing the spheres from the setting bath I like to thoroughly rinse them one by one. If possible have two batches of rinse water handy. The first will remove any ungelled sodium alginate solution, the second will act as a final rinse before storage. It is possible for spheres to bond together with just one rinsing bath. For final storage place them in either neutral flavored oil or a fresh bath of the clear flavorful liquid. These spheres can be made hours if not days ahead of time and stored until needed. If you are making ravioli sized spheres the best plan of attack is to use reverse spherification.
Give our Pickled Mustard Seed Sphere recipe a try! Best served at room temperature, this dish was inspired by our desire to push the boundaries of Reverse Spherification. We wanted to see if it was possible to create texture within the sphere using mustard seeds. To get the recipes in the full Mustard Sphere dish and more, sign up for our newsletter to be among the first to be notified on exclusive releases from the Kitchen Alchemist’s Notebook.