Hydrocolloids for Cooks

Transcription

Hydrocolloids for Cooks
Hydrocolloids
For Cooks
By Eddie Shepherd
A simple introduction to hydrocolloids & other modern
ingredients for chefs & home cooks.
Version:1
In association with
WWW.MODERNIST-CHEF.COM
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Hydrocolloids For Cooks
A simple introduction to hydrocolloids & other modern
ingredients for chefs & home cooks.
In association with
WWW.MODERNIST-CHEF.COM
The online shop for modern ingredients and equipment run by cooks for cooks. All
the ingredients discussed in this handbook are available at www.Modernist-Chef.com
By Eddie Shepherd
The Blog - www.VeggieChef.co.uk
The Book -www.EddieShepherd.com
Introduction
Agar Agar
Sodium Alginate
Gellan Gum
Xanthan Gum
Methyl-cellulose
Kappa Carageenan
Iota Carageenan
Locus Bean Gum
Gum Arabic
Hydrocolloids in Synergy
Soy Lecithin
Isomalt
Kuzu
Calcium Salts (Calcium Chloride, Lactate & Gluconate)
Sequestrants
Spherification
Reverse Spherification - Examples
Direct Spherification - Examples
References
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Introduction
I hope this handbook can serve as a simple introduction to hydrocolloids and some other modern
ingredients. More in depth information is available and referenced on the last page but I aim for this
to be a handy and accessible guild suited to cooks and those starting out with these ingredients.
This is the first version of this handbook so please forgive any typing errors etc and do contact me
with any feedback with regards to this version and what you would like to see in future editions.
Most hydrocolloids are very natural ingredients derived from plants, seaweed and bacteria.
Broadly speaking the hydrocolloids we are concerned with are gelling/thickening agents made up of
complex sugars (polysaccharides) which can form a gel or act as a thickener when hydrated.
Typically culinary hydrocolloids are used in very low concentrations and different hydrocolloids
have different properties, so they aren’t simply interchangeable and they need to be used with a
degree of precision. This handbook should give you some guidance, help you make a decision of
which ingredient suits your need and how to use it.
The recipes given here are basic and designed just to get you started with these ingredients and
techniques. More detail and more elaborate recipes are easy to find and some good places to go for
further information and recipes are referenced at the end of the handbook.
General Tips
All hydrocolloids must be properly hydrated for effective repeatable results. This begins with good
dispersion of the ingredient.
There are serval ways to ensure that your hydrocolloids are dispersed well enough in the liquid that
they will dissolve without forming lumps.
They can be mixed with another ingredient in powder form, such as sugar or a maltodextrin, to
physically separate out the hydrocolloid particles so that it disperses more easily without clumping
(similar to the way we use a butter and flour mixture in a roux to separate the flour particles to stop
them forming lumps).
You can also blend your liquid and keep it moving as you add your hydrocolloid to make sure you
get good dispersion. Running the liquid base in a blender and then gradually sprinkling the
hydrocolloid into to the vortex is a good way to do this
It is also worth mentioning the need for some precision in using these ingredients.
Due to the typically low concentrations of hydrocolloids being used in culinary applications often
scales which measure to 0.01 of a gram are a necessity for accuracy.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
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Agar
Origin - Seaweed
Generally Use - 0.2% to 2%
Key Characteristics - Forms a brittle Gel. Versatile ingredient, uses include - Gels, Fluid Gels,
Foams, Clarification, Cold Oil Spherification.
Agar is derived from seaweed and in modern cooking is primarily used as a gelling agent or
thickener.
For gelling Agar needs to be hydrated in a liquid and heated up to around 90°C in order for it to set
as it cools.
When cooling Agar will set rapidly at around 35°C
Once an Agar gel has been formed it won’t melt again until it reaches 80-90°C.
Gelling Here’s a very basic recipe that can be used as a rough template from which you change the flavours
and desired yield etc. (Note - this is an intentionally simplistic base recipe, for best results adapt
and refine this according your needs)
300g Liquid
2.5g Agar (0.8%)
Whisk the Agar into the liquid and place it on the heat. Bring to a simmer slowly whilst stirring.
Hold at a simmer for 2 minutes.
Pour out the liquid into a plastic container or a prepared mould and leave to cool and set.
The mixture will set rapidly into a gel once it cools to around 35°C.
Agars higher melting point means gels can be served warm or hot.
Fluid Gels To prepare an Agar fluid gel first set a gel from your chosen flavoured liquid (following the
directions for ‘Gelling’).
Then simply blend the set gel until it reaches a smooth consistency. The consistency of the fluid gel
can then be altered as desired by either thinning with more liquid or thickening with xanthan gum.
Foams Agar fluid gels can be used to make foams by pouring the fluid gel into a cream whipper and
charging it with nitrous oxide then dispensing the foam when ready to serve. Or fluid gels can even
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be carbonated, by placing in a cream whipper, charging with Co2 then chilling before dispensing
just as ready to serve.
Cold Oil Spherification A liquid is prepared via the same method as with making a gel but rather than being allowed to cool
and set it is cooled to around 50-60C then, using a pipette, syringe or squeeze bottle, droplets are
dropped into ice cold oil (chilled in the freezer) so small gel spheres form in the oil and are quickly
set due to the low temperature of the oil.
Clarification A weak agar gel is made (around 0.25%) then the gel is gently broken with a whisk. This broken gel
is then hung and gently strained though muslin. It should yield a clarified liquid.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
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Sodium Alginate
Origin - Seaweed
Generally Use - 0.5% - 1%
Key Characteristics - Forms a gel in the presence of calcium ions. Gel is elastic and heat resistant.
Used for the famous techniques of Direct Spherification (to make small liquid centered caviar like
pearls) and Reverse Spherification (to make larger liquid centered orbs of flavourful liquids)
Sodium alginate rapidly forms a gel in the presence of calcium, these gels are heat stable (they
won’t melt) to above 150°C.
Note - Alginate does not work properly with mixtures which are too acidic (below 3.5PH). It is
possible to adjust the ph of your mixture using a sequestrant such as Tri Sodium Citrate, see the end
of this section or the section on Sequestrants for more detail.
Sodium alginate is used in a technique known as spherification in which fruit or vegetable juices etc
are turned into 'caviar', or larger spheres, which burst in the mouth. Typically this requires using a
calcium salt such as calcium chloride (which can be bitter) or calcium gluconate (more pleasant
flavour but requires around twice as much as calcium chloride).
Alginate mixtures should be allowed to settle after blending in order to allow the alginate to fully
hydrate and trapped air to escape from the mixture. Two hours in the fridge is ideal.
Store finished spheres in a flavourful liquid without any added calcium or alginate, or in a neutral
oil.
Direct spherification A flavourful solution containing sodium alginate is dropped into a calcium bath which triggers the
alginate solution to start gelling from the outside slowly inwards. The small spheres are then rinsed
and if served soon after this the spheres will be set on the outside but liquid in the centre. These
spheres will eventually set solid all the way through so need to be made close to serving time.
Alginate is usually added to the flavourful liquid at 0.5% - 1%
Reverse spherification A flavourful calcium rich solution is dropped into a bath of sodium alginate. This liquid may be
naturally calcium rich or have a neutral flavoured calcium salt, such as calcium gluconolactate,
added to it. The calcium causes the sodium alginate to gel into a thin film around the flavourful
liquid, creating a liquid centered sphere. This method can be preferable as the spheres will not
continue to set after the sphere is formed (more practical for making in advance or in batches). This
method is used to produce larger spheres.
Sodium Alginate baths tend to use sodium alginate at 0.5-0.8% of the total liquid.
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Flavourful liquids for reverse spherification which aren’t naturally calcium rich should have
calcium gluconolactate added at 2%
Sodium Alginate Bath for Reverse Spherification 5g Sodium Alginate
1 Liter Water (use either distilled water or low calcium water such as volvic)
Blend the water in a blender then gradually sprinkle in the sodium alginate. Blend until the sodium
alginate is well dissolved.
Let this solution settle in the fridge for two hours (it will appear clearer when settled).
This bath can now be used for reverse spherification (see the section on spherification for more
information and recipe)
Watermelon ‘Caviar’ Direct Spherification
250ml Watermelon Juice
50g Caster sugar
15g Lemon juice
1.5g Sodium Alginate (0.5%)
Combine the liquids in a blender, then while blending add in the caster sugar and sodium alginate.
Strain though a fine sieve to help get rid of air bubbles, then allow to settle in the fridge for two
hours before using.
Drop small amounts of this mixture into a calcium bath using a syringe, pipette or multi dropper
tool.
Allow the caviar to react for thirty seconds then remove with a slotted spoon and rinse in a bath of
fresh water.
Serve as soon as possible after making.
(If using an acidic ingredient for direct spherification refer to the information below)
Adjusting PH with sodium citrate Sodium Alginate does not work properly with liquids which have a ph of 3.5 or bellow. To raise the
ph of liquids to make them useable with sodium alginate for direct spherification add sodium citrate
to the liquid guided by the percentages given bellow.
TO GET A USABLE PH OF 5 ADD SODIUM CITRATE TO THE LIQUID AS FOLLOWS –
LIQUID PH 2 – ADD 0.3% Tri Sodium Citrate
LIQUID PH 2.5 – ADD 0.09% Tri Sodium Citrate
LIQUID PH 3 – ADD 0.03% Tri Sodium Citrate
LIQUID PH 3.5 – ADD 0.01% Tri Sodium Citrate
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Gellan
Origin - Microbial Biofermentation
Generally Use - 0.5% - 1%
Key Characteristics - Gel forming, Sensitive to Calcium.
Low Acyl Gellan - forms firm, brittle gels.
High Acyl Gellan - forms soft, elastic gels.
Gellan comes in two types - High Acyl Gellan or Low Acyl Gellan, the two types can be used
together to achieve the chefs desired texture.
Typically is used to form gels or fluid gels, as a stabilizer, or in very low concentrations to suspend
particles or small objects (such as fruit juice spheres) in a liquid.
A gellan gel has the advantage of having quite a high melting temperature, 80C or even above. For
that reason it is sometimes used for creating hot gels or as an ingredient in ice-cream or sorbets
which can be flamed with alcohol.
Gelling
To gel blend gellan into cold liquid and slowly heat to a low simmer while whisking. Pour out and
allow to set.
Fluid Gels
For a fluid gel either continuously blend the gellan as it cools or allow it to set into a gel then puree
that gel.
Other
Gellan’s sensitivity to calcium means it can also be used for spherification with the right conditions.
Also in very low concentrations gellan can be used to suspend particles (or fruit ‘caviar’ etc) in a
liquid, holding them in place in a way that seems to defy gravity. Also at low concentrations two
equal gellan strength solutions can be contained in the same vestal without them mixing. Heston
Blumenthal uses this effect cleverly in serving a glass of tea which is iced cold if drunk from one
side of the glass but hot tea if consumed from the other side of the glass as the two temperature
liquids containing gellan remain separate without any physical divider.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Xanthan gum
Origin - Microbial Fermentation
Generally Use - 0.2%-1.5%
Key Characteristics - Thickener and Emulsifier
Xanthan blends into liquids hot or cold. It is extremely easy to use, chefs often use it to quickly
thicken sauces or purees, to alter consistency, to stop sauces from weeping or to stabilize emulsions.
Xanthan gum can also help to give food a rich, creamy mouthfeel.
It’s frequently used in modern cooking for its thickening and stabilizing properties.
It is cold thickening so there is no need to heat it, it can just be blended directly into liquids to
thicken them.
Therefore it can be used with liquids you wouldn’t want to heat for a variety of reasons.
Xanthan Gum is frequently used along with other hydrocolloids - for instance in stabilizing foams.
Xanthan gum is often used in frozen desserts such as ice creams and sorbets as it helps to prevent
the formation of larger ice crystals, so maintaining a smoother texture. It can also provide a pleasant
mouth feel and give the impression of a higher fat content it’s a great ingredient to have on hand
and is really useful to be familiar with.
Xanthan gum will not form a gel on its own but in synergy with Locus Bean Gum it can form an
elastic gel. See the ‘Hydrocolloids in synergy’ section.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Methyl-cellulose F50
Origin - Cellulose from plants
Generally Use - 0.75% - 2%
Key Characteristics - Can form a gel while hot which melts as it cools. Acts as a whipping or
foaming agent. Can aid crispness in deep frying applications
Note - For many applications it is useful to use methyl-cellulose in the form of a prepared hydrated
methyl-cellulose slurry (recipe on the next page).
Particular to Methyl-cellulose is that it gels when its heated rather than once it cools.
Methyl-cellulose has a number of uses inducing - forming hot gels (gels at around 65C), as a
whipping agent for making foams or as a egg white replacement, forming an oil impermeable film
in deep frying, or as a replacement for egg wash in breadcrumbed products.
Methyl-cellulose mixtures can be whipped to provide structure for meringue (as with the beetroot
meringue recipe I provide on the next page).
It’s also used in some deep fried foods, as when it comes into contact with the hot oil in a fryer it
forms a film.
Due to this, using methyl-cellulose in batters both reduces the amount of moisture which escapes
from the coated ingredient and also reduces the amount of oil absorbed into the coated item. This
can help to achieve a crispier, lighter product with a great texture.
One way of using methyl-cellulose in recipes is to prepare a slurry by first mixing it into hot water,
then stirring this as it cools. This way the methyl-cellulose won't clump and will be well dispersed
as it cools and begins to hydrate. The recipe for this approach appears on the next page.
Because of this unique quality it’s often used to make mousses and geleés which are firm when they
are hot but melt as they cool.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Methyl-Cellulose Example Recipes
Here i’m including the beetroot meringue recipe from my first book because it has proved so
popular and so many people ask about it.
Methyl-cellulose Slurry 3g Methyl-cellulose
200ml Water
Boil the water in the kettle then measure out 200ml of just boiled water.
Now blend the Methyl-cellulose into the hot water with a stick blender.
Now begin to cool this mixture over an ice bath, while stirring intermittently, until cool.
Allow this mix to sit for at least a couple of hours but for best results sit in fridge overnight.
It will be thick and transparent when ready. At this stage store in the fridge or freezer until needed.
Beetroot Meringue (Example Recipe)
45g Prepared Methyl-cellulose Slurry
260g Beetroot Juice
1.2g Xanthan gum
40g Isomalt
10g Caster sugar
First prepare the Methyl-cellulose Slurry.
Next blend together the beetroot juice, methyl-cellulose slurry and xanthan gum with a stick blender
and season to taste.
Then in bowl start whipping this mixture with an electric whisk and add in the isomalt and caster
sugar bit by bit.
Whip this mix to soft peaks, this will take a little time (more than whipping egg whites) but will go
to stiff peaks eventually if you persist.
Now either pipe neat blobs of the beetroot meringue mixture onto a non stick sheet or spread the
mix as a thin layer.
FInally dehydrate the meringue at 57°C for 10-12 hours until dry and crispy (or place in a low oven
as close to these temperatures and times as possible). Store in air tight containers with silica.
This technique can be adapted for a wide variety of juices.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Carrageenan
Origin - Seaweed
Generally Use - 0.75-1% in water
Generally Use in dairy products - 0.35-0.5%
Key Characteristics - Forms gels. Frequently used with dairy as in presence of calcium only a small
amount of carrageenan is necessary to form a gel.
Carrageenan for culinary use come in two types - Kappa and Iota
Kappa Firm and Brittle gel
Low concentration needed with milk
Iota Elastic gel
Low concentration needed with milk
Like agar gels those made with Iota carrageenan can be blended to a fluid gel - a smooth purée.
For fluid gels use set gels which were made with between 0.2% and 1% Iota carageenan. The
weaker the gel the thiner the fluid gel and the stronger the gel the thicker the fluid gel will be.
These fluid gels can also be foamed using a cream whipper. The thiner the fluid gel the lighter the
foam, and the thicker the fluid gel the denser the foam.
To set gels with carrageenan disperse the powder into a liquid while cold then heat to a simmer
while whisking. Hold briefly at a simmer then pour out into a container to set.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Locust Bean Gum
Origin - Carob seeds
Generally use - 0.5% - 1%
Used to thicken liquids or stabilize mixtures. It is synergistic with carrageenan and xanthan gum.
(See the section on hydrocolloids in synergy)
Blend into liquids to use as a thickener or stabilizer, or combine with other hydrocolloids such as
carrageenan or xanthan gum and heat together then cool to form gels. These gels are sometimes
used to replicate gelatin gels as they can have some similar features.
Locus bean gum can is used sometimes to improve the texture of dairy products such as cream
cheese and ice-cream.
Gum Arabic
Origin - Sap
Generally Use - 1% - 2 % (but can be used to much higher percentage for thickening)
Key characteristics - Emulsifier and limits ice crystal growth in frozen products
Used mostly as an emulsifier (in very high concentrations will also thicken). It can be blended into a
liquid cold or hot.
Characteristic of gum arabic’s emulsifying properties - emulsions can be formed and then diluted
without breaking the emulsion.
The addition of gum arabic to frozen products can help limit the size of ice crystal growth, so it may
be used in frozen preparations such as ice cream to keep their texture smooth and assist in them
being resilient to freeze thaw cycles within the freezer.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Hydrocolloids in synergy
Some hydrocolloids have synergistic properties and when combined create something different form
what is possible when using them alone.
Kappa and Locus Bean Gum
Blend Ratio - 60% Kappa Carageenan 40% Locus Bean Gum
Generally use - 0.5 - 3%
Creates a strong gel with some similar properties to gelatin. In fact often used as a gelatin
replacement.
To use Mix with liquid cold.
Slowly bring to simmer.
Sets as it cools.
Xanthan Gum and Locus Bean Gum
Blend Ratio - 50% Xanthan 50% Locus Bean Gum
Generally use - 0.5 - 2%
Forms an elastic chewy gel with quite a unique texture and a strange but pleasant mouth feel.
Wobbles like gelatin jelly.
To use Mix with liquid cold.
Slowly bring to simmer.
Sets as it cools.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Other Ingredients
Not Hydrocolloids but interesting ingredient which I thought would be useful to include.
Soy Lecithin
Origin - Soy Bean Plants
Use - 0.2% - 1%
Key Characteristics - Soy Lecithin can be used both to create emulsion and to make light stable
foams known as ‘Airs’
Soy Lecithin occurs naturally in soy bean plants and is then extracted.
Lecithin is an emulsifier which is also found in egg yolks (this is why we traditionally use egg yolks
to emulsify dressings etc).
Soy Lecithin is a particularly useful emulsifier as it is dairy and egg free and can be added to
mixtures in precise amounts.
Emulsions are a mixture of liquids which are usually immiscible (won't mix or they separate out).
Emulsifiers such as Soy Lecithin allow us to combine these immiscible liquids and have them
remain mixed and stable (for example an oil and water emulsion like a salad dressing).
Lecithin is also a surfactant and can be used to produce stable, light foams known as ‘Airs’
These have an incredibly light texture and vanish immediately in the mouth but can carry strong
flavours without adding volume to a dish.
For an ‘Air’ typically add 0.3% -1% Soy lecithin to a thin liquid and froth with a stick blender.
Spoon the resulting light foam onto you dish when ready to serve.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Isomalt
Origin - Sugar Alcohol made from beetroot
Use - NA
Key Characteristics - It is slightly less sweet than caster sugar and has fewer calories. It is also less
hydroscopic than sugar and remains clear & transparent once heated and cooled for sugar work.
Isomalt is a sugar substitute treated with enzymes.
It copes better with humidity than conventional sugar and is less prone to crystallization. Because of
this it is popular with pastry chefs for sugar work and decorations.
Isomalt stays clear even when heated up 180°C and so has a different look to sugar work produced
with normal sugar.
It is sometimes used where a sugar structure is necessary but full sugar sweetness isn’t desired or
for a longer shelf life than conventional sugar.
Isomalt stays flexible a little longer than conventional sugars when hot and so is easier to work with
when pulling sugar and creating decorations.
Isomalt can be used to make a number of sugar decorations and fine delicate tuiles.
Cinnamon Tuile Example Recipe 60g Isomalt
Pinch Ground Cinnamon
Gently heat the isomalt in a pan to 160C to melt it evenly – stirring as little as possible.
Pour out the isomalt onto a silicon mat and allow it to set.
Grind the set pieces of isomalt to a powder in a spice grinder.
Sieve the powdered isomalt onto a silicon baking mat.
Lightly sprinkle over a tiny pinch of cinnamon
Place the silicon mat in a 120C oven for 1-2 minutes until the isomalt is melted.
Remove from the oven and allow it to cool for a moment then then gently lift away pieces of the
delicate cinnamon tuile.
Store these in an airtight container with silica crystals.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Kuzu Origin - Starch derived from the roots of a japanese plant
Use - 0.5% - 10%
Key Characteristics - Kuzu is a neutral flavoured starch which acts a thickener. It is gluten free. Can
be used to create fruit or vegetable juice ‘glass’ (thin, transparent, brittle tuiles).
For use as a thickener it must first be dissolved cold. Then when heated kuzu thickens the liquid it is
dissolved in and turns it translucent.
It can also be dissolved in a little cold water then added into an already hot liquid towards the end of
cooking (ie to thicken a sauce).
It is a traditional ingredient in Japan but can also be used for modern applications such as making
'glass' or tuiles with fruit or vegetable juices.
It can create a variety of brittle textured thin sheets when it is used to thicken a liquid which is then
dehydrated.
Kuzu can also be powdered and used as a coating for deep frying to enhance crispness.
Kuzu is gluten free and easy to work with and so is also often used in catering for dietary
restrictions but it is its ability to make puree textures, ‘glass’, tuiles which can be deep fried etc
which makes it of interest in more avant-garde cooking
Kuzu Fruit Glass Base Recipe 20g Kuzu
20g Caster Sugar
20g Isomalt
200g Liquid - ie fruit or vegetable juice
Mix all the ingredients together cold and stir until dissolved.
Gently heat this mixture in a pan while stirring. It will suddenly begin to thicken and turn
translucent.
Once evenly thickened and translucent remove the pan from the heat.
Whilst hot spread the thickened mixture as thin as possible on a non-stick mat (either a silicon
baking mat or dehydrator sheet)
Dehydrate at 68C for 14 hour, or if you don’t have access to a dehydrator place in an oven set as
close to 70C as possible overnight until dry and crisp.
The finished fruit glass can be stored in an airtight container with silica crystals.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Calcium Salts
Origin - Various
Use - 0.5% - 5% depending on which calcium salt and which application
Key Characteristics - The characteristic most relevant to cooks is their positively charged calcium
ions which can cause some hydrocolloids to gel in their presence.
See example uses in the spherification section.
Hydrocolloids such as sodium alginate and gellan can form a gel in contact with the positively
charged ions present in calcium salts. Others such as kappa carageenan are also sensitive to the
presence of calcium which can effect how they work (in the case of carageenan a much smaller
amount of the hydrocolloid is needed to create gel a calcium rich liquid such as milk).
There are several types of calcium salt which are frequently used in cooking for methods such as
spherification.
Calcium Chloride has a unpleasant flavour, but is cheap and has a high calcium content. This
makes it best suited for use in a calcium bath for direct spherification, so long as spheres are rinsed
to remove any unpleasant taste once they are removed from the calcium bath.
Use at 1% for a standard calcium bath.
Calcium Gluconolactate (a mixture of calcium lactate and gluconate) has a neutral flavour, but its
is more expensive and has a lower calcium content that calcium chloride. Use at 2% to add to a
flavourful liquid for direct spherification.
For consistency when working with calcium sensitive hydrocolloids I use bottled water with with a
calcium content of less than 15mg/liter. Volvic is a good bet as it’s calcium level is 11.5mg/liter.
In some cases the amount calcium in a liquid (even tap water) can cause the hydrocolloid to begin
to gel immediately, this can be particularly problematic with sodium alginate in spherification. In
this case sequestrants may be used to prevent this pre-gelling.
For example recipes see the spherification section.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Sequestrants
The sequestrants we are concerned with can perform two functions.
1) They can raise the PH of liquids (make acidic mixtures more alkaline), which is particularly
useful when using PH sensitive ingredients like sodium alginate.
2) They can bind positively charged ions such as calcium ions so they do not effect the workings of
an ingredient which is sensitive to calcium, such as sodium alginate or gellan.They do this by
essentially being better at linking to the calcium ions than the hydrocolloids are. So few calcium
ions are left free to interfere with the action of the hydrocolloid.
Sodium Citrate
Sodium Citrate is a popular sequestrant. It is very useful in raising the PH of mixtures used in direct
spherification.
It is also used to sequester calcium ions at 0.1%-0.2% of the mixture, how ever it only works in this
function to down to a PH of 4.
Adjusting PH with sodium citrate To raise the ph of acidic liquids add Tri Sodium Citrate with refer to the percentages given bellow.
FOR A PH OF 5 ADD TRI SODIUM CITRATE TO THE LIQUID AS FOLLOWS –
LIQUID PH 2 – ADD 0.3% Tri Sodium Citrate
LIQUID PH 2.5 – ADD 0.09% Tri Sodium Citrate
LIQUID PH 3 – ADD 0.03% Tri Sodium Citrate
LIQUID PH 3.5 – ADD 0.01% Tri Sodium Citrate
Sodium Hexametaphosphate (SHMP)
Sodium Hexametaphosphate can also be used to raise the PH mixtures which are too acidic.
It is also used to sequester calcium ions and used at 0.1%-0.2% will work well for this in all
necessary PH.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Spherification
This is the technique famously developed by Ferran and Albert Adria of El Bulli
Sodium alginate is used in this technique to turn fruit or vegetable juices into 'caviar', or larger
spheres, which burst in the mouth. Typically this requires using a calcium salt (see the section on
calcium)
Alginate mixtures should be allowed to settle after blending in order to allow the alginate to fully
hydrate and trapped air to escape from the mixture. Two hours in the fridge is ideal.
Note - When using different ingredients consider how their calcium content or acidity may effect
the recipe. Refer to the sections on sodium alginate & sequestrants for details and how to correct
for this. For instance by adding a sequestrant such as Tri Sodium Citrate.
Its a good idea for consistency to use either distilled water or bottled water with with a calcium
content of less than 15mg/litre. Volvic is a good bet as it’s calcium level is low at 11.5mg/litre.
Store finished spheres in a flavourful liquid without any added calcium or alginate, or in a neutral
oil.
Direct spherification A flavourful solution containing sodium alginate is dropped into a calcium bath which triggers the
alginate solution to start gelling from the outside slowly inwards. The small spheres are then rinsed
and if served soon after this the spheres will be set on the outside but liquid in the centre. These
spheres will eventually set solid all the way through so need to be made close to serving time.
Alginate is usually added to the flavourful liquid at 0.5% - 1%
Reverse spherification A flavourful calcium rich solution is dropped into a bath of sodium alginate. This liquid may be
naturally calcium rich or have a neutral flavoured calcium salt, such as calcium gluconolactate,
added to it. The calcium causes the sodium alginate to gel into a thin film around the flavourful
liquid, creating a liquid centered sphere. This method can be preferable as the spheres will not
continue to set after the sphere is formed (more practical for making in advance or in batches). This
method is used to produce larger spheres.
Sodium Alginate baths tend to use sodium alginate at 0.5-0.8% of the total liquid.
Flavourful liquids for reverse spherification which aren’t naturally calcium rich should have
calcium gluconolactate added at 2%.
Thin liquids are often thickened a little in order to work with more easily and achieve nice shaped
spheres, using xanthan gum between 0.1% - 0.5%.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Reverse Spherification - Example Recipes
Sodium Alginate Bath for Reverse Spherification 5g Sodium Alginate
1 Liter Water (use either distilled water or low calcium water such as volvic)
Blend the water in a blender then gradually sprinkle in the sodium alginate. Blend until the sodium
alginate is well dissolved.
Let this solution settle in the fridge for two hours (it will appear clearer when settled).
This bath can now be used for reverse spherification (see the section on spherification for more
information and recipe)
Simple Yoghurt & Honey Reverse Spherification
(This recipe does not require addition of calcium gluconolactate as the yoghurt is naturally rich
enough is calcium)
200g Natural Greek Yoghurt
40g Honey
Pinch Cracked Black Pepper
Mix together well.
Drop small spoonfuls of this mixture into a bath of sodium alginate, spaced out well. Allow to react
for 30-60 seconds.
Remove from the bath with a slotted spoon and rinse in a bath of fresh water.
Store in neutral oil until ready to serve.
Generalized Base Recipe - Flavourful liquid for reverse spherification (To get this liquid to a viscosity which is easy to use for this technique the liquid can be thickened
with a little xanthan if too thin)
300ml Flavourful liquid
6g Calcium Lactate Gluconate (2%)
Xathan Gum if necessary for consistency (up to around 1%)
Use a dropping spoon (a small rounded hemisphere spoon) to drop small amounts of the liquid into
a sodium alginate bath. Allow to react for 30-60 seconds.
Remove from the bath with a slotted spoon and rinse in a bath of fresh water.
Store in neutral oil until ready to serve
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
Direct Spherification - Example Recipes
Calcium Chloride Bath for Direct Spherification 10g Calcium Chloride
1lt Water
Mix together well until the calcium chloride is fully dissolved.
Watermelon ‘Caviar’ Direct Spherification
250ml Watermelon Juice
50g Caster sugar
15g Lemon juice
1.5g Sodium Alginate (0.5%)
Combine the liquids in a blender, then while blending add in the caster sugar and sodium alginate.
Strain though a fine sieve to help get rid of air bubbles, then allow to settle in the fridge for two
hours before using.
Drop small amounts of this mixture into a calcium bath using a syringe, pipette or multi dropper
tool.
Allow the caviar to react for thirty seconds then remove with a slotted spoon and rinse in a bath of
fresh water.
Serve as soon as possible after making.
(If adapting this recipe for an acidic ingredient refer to the either the sodium alginate or
sequestrants sections for details of how to do this)
Generalized Base Recipes Generalized Base Recipe - Flavourful liquid for direct spherification (If the liquid is more acidic that 3.5 PH use Soium Citrate to first raise the PH above 3.5 before
creating spheres)
300ml Flavourful liquid (PH above 3.5)
1.5g Sodium Alginate (1.5%)
Use a pipette, syringe or multi dropper to drip this liquid into a calcium chloride bath.
Allow the resulting spheres to react for 30 seconds then using a slotted spoon remove and rinse in a
bath of fresh water.
Serve as soon a possible.
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com
References
All the ingredients featured here are available from the
Modernist-Chef online shop.
WWW.MODERNIST-CHEF.COM
See more from Eddie Shepherd The Books www.EddieShepherd.com
Eddies Inspiring Digital Cookbooks
The Blog www.VeggieChef.co.uk
Eddies Blog
Videos Eddies Youtube Channel
Some other recommended references on the
subject Cooking Issues
Chef Steps
Modernist Cuisine
Klymos
‘Hydrocolloids for Cooks’ by Eddie Shepherd
www.Modernist-Chef.com