Spherification is food turned seriously cool. Not only does it look fantastic and smart, it’s actually really simple to do. My mango spherification is easy enough for anyone to whip up in their kitchen and impress their dinner guests.
While the processes and ingredients might seem foreign to most kitchens, it’s only as foreign as a microwave or instant coffee were some decades ago. The ingredients aren’t crazy synthesised chemicals – they’re vegetarian and have their roots in nature just like refined sugar and honey does. (NB: I pretty certain they’re vegan, but didn’t want to stick my neck on the line!)
I first got into spherification when I was at catering college, and I was surprised at how cheap the ingredients were. I even started making up and selling spherification kits on eBay, and this mango spherification was on the recipe cards I provided with the kits!
One reason why the uptake on the use of spherification might be slower than expected (considering its affordability and simplicity) may be because the application of it hasn’t been refined very much. It still hasn’t moved passed ‘cool and quirky,’ with few serious dishes that use the process well (away from high end restaurants), making it more of a gimmick than a serious tool. But there are some serious uses of this method, which I’ll be exploring in the coming months (liquid centre jellies and raviolis, and some cool cocktails to name but a few). Even though bubble tea is made using tapioca, there’s no reason spherification wouldn’t work as well (plus being far more versatile).
[A personal note is that calling it things like ‘sodium alginate’ and ‘calcium lactate’ that keeps it exclusive. Changing the names to bath-starter and sphere-starter, or sphere bath powder and sphere liquid powder, or even Mary and Dave, would make people a lot more confident in using it. No one sniffs at using baking powder, do they?]
So what is Spherification??
It all centres around a ingredient called sodium alginate (pun intended). As chemical as that sounds, it’s actually refined from seaweed. The unique property that sodium alginate has is how it forms a gel when it comes into contact with calcium. Bonus for us is that it’s also flavourless, and perfectly healthy. So we exploit this property to form a film of gel around liquid and semi-liquid substances, allowing them to hold their shape in a contained ball.
There are two methods to doing this: spherification, and reverse spherification.
Spherification is where we mix the alginate with our liquid of choice, and place it into calcium-rich water. The alginate within our liquid then turns into a gel almost immediately, and thus a spherification ball is made.
Reverse Spherification turns this process around (hence the name). Our chosen liquid in enriched with calcium, and we place this into a bath full of alginate. Using this method, our liquid doesn’t gel. Instead, the outside of the liquid starts to form a gel film, which continues to thicken as long as it remains in the alginate bath.
To think of it another way – spherification is where the alginate gel film comes from the edges of our liquid inwards, and reverse spherification is where the alginate gel film forms from the edge of our liquid outwards.
So why would the difference matter?
One large flaw with standard spherification is that the liquid continues to gel even when it is removed from the calcium bath. So what starts off as a liquid centre ball will eventually harden into a complete gel ball. This loses most of the fun of spherification, and also hinders its practical purposes.
But it has its benefits as well – if served immediately, it still is liquid inside. It forms much smaller and more perfectly formed balls (often called caviar due to its similarities in appearance). When making the balls, they are free to touch each other and they won’t stick (a difficulty with reverse spherification). Spherification creates spheres that are strong and don’t burst easily. And most importantly – it’s far easier to use standard spherification when we’re sphering very thin liquids like juice and alcohol.
Reverse spherification ceases the moment the spheres are taken out of the alginate bath, so the film that is formed won’t get any thicker. This benefits us as we can then use the spheres for other applications at a later time (I have a recipe for liquid centre jellies coming soon). The spheres can be made hours in advance, and can even be heated in water over a hob.
The negatives are that the spheres are fragile and break frequently, especially if taken out of the alginate bath too quickly. If the spheres are left in the alginate bath for too long, they form a thick skin which can be a little unpleasant to eat. And mainly – it really doesn’t work for thin liquids, and liquids that don’t mix with calcium well. The alginate bath is quite viscous, so the thin liquid either doesn’t go into the bath at all and just sits on the top, or it doesn’t form a neat sphere and looks a mess. Saying that, it’s still quite difficult to get a perfect sphere even using a thicker liquid (so we often freeze the liquid in a mould, so when it enters the bath and defrosts, it holds its shape perfectly).
So it’s as simple as that? There are some other considerations regarding alcohol/acidity and adding calcium to some liquids, but for the large part it really is that simple. As reverse spherification is the easiest method, my mango spherification will use this to demonstrate how it works. Plus mango is delicious and easy to get hold of. I’ll be doing a standard spherification recipe soon!
- 1 litre Bottled water
- 5 g Sodium Alginate
- slices Tin mango
- 1 tbsp Caster sugar
- Squeeze of lemon juice
- 3 g Calcium Lactate
- Pour 800ml of water in to a flat bottomed container
- Blend in 4g Sodium Alginate using a hand/immersion blender – (Alginate Bath) - water will go cloudy
- Place in fridge for at least 1 hour until bubbles have gone
- Weigh approximately 150g of mango from the tin
- Blend with 1 tbsp of caster sugar and squeeze of lemon juice – adjust both to taste
- Stir in 3g Calcium Lactate and add 1-2 tbsp of water to thin the puree slightly
- Spoon puree in to Alginate Bath to form spheres (½ teaspoon gives a good size). Move the spheres around to coat on all sides, but don't let them touch or they'll stick to each other!
- Remove after 1 minute with metal slotted spoon (leave for longer if spheres burst easily, less if too thick skinned)
Why are you using bottled water? Here in the UK, we often treat our tap water with fluoride and other additives, which can interfere with the process and stop it working. When I first tried this with tap water, the alginate bath turned to a gel immediately! I use the 17p bottled water from Asda, as even the cheapest water will do. Just make sure it’s not ‘mineral water’ as these minerals are exactly what we’re trying to avoid!
Why do we need to wait for the bubbles to go from the alginate bath? You don’t have to wait. But them bubbles can (and will) transfer into the spheres, so they lose their clean-edged charm. Some places tell you to leave the bath for 12-24 hours, but I really have no idea why this is. 1 hour has always been perfectly satisfactory for me.
My spheres keep bursting. You either need to leave them in the alginate bath for longer, or add a little more calcium lactate to the mango puree. This will create a thicker skin which should hold better. Or you need to be more gentle with your spheres!
The skin on my spheres is thick and chewy. Take the spheres out of the bath much sooner! Do the spheres in small batches, so the first sphere isn’t sitting in the bath for too long before the last one is finished. Rinsing the spheres in water at the end removes some of the gel membrane, and you can also use kitchen roll to gently remove some as well. But this is a very delicate process, so only do so if absolutely needed.
Why do we need to use an immersion/stick blender to mix in the sodium alginate into the water bath? I’m not entirely sure of the chemistry behind it, but the sodium alginate sticks together as a sort of paste, floating on top of the water. We use an immersion blender to break these bonds violently, and agitate the sodium alginate into making bonds with the water. It needs a blender to do this – a whisk won’t suffice.
Does this work for any liquid or puree? As far as I’m aware, it does. Some liquids won’t mix with the calcium effectively, but will mix with the alginate syrup (like fruit juices and alcohol, for instance), while some liquids are too thin to create a decent sphere within the alginate bath. So in these cases, we’re limited to just the standard spherification model. If the liquid has a high calcium content, standard spherification won’t work as it will gel when mixed with the alginate syrup. Standard spherification doesn’t work for highly acidic liquids either, but this can be altered using alkaline additives.
How much sodium alginate and calcium lactate do I use if I’m changing ingredients? I’ve used the following scaling: 0.5% of water weight to sodium alginate; 2% calcium lactate to weight of liquid/puree. You may need to adjust this calcium lactate addition, depending on the calcium content of your liquid or puree.
Can I reuse my alginate bath? Sure, I certainly do! But I wouldn’t use it after more than a day or so. Like anything – bacteria will start to form and make it unhealthy to continue using. Also consider any contamination you might be bringing in every time you spoon in a new liquid. If in doubt, make a new bath.
Does the sodium alginate or calcium lactate affect the flavour at all? The calcium can impart a very slight flavour change, but it’s not perceptible at these concentrations unless you’re looking for it or putting far too much in. The sodium alginate is totally flavourless, but the skin that reverse spherification forms can be unpleasant to some people.