Agar Agar

Agar Agar
An Introduction and four techniques

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Agar is such a fantastic and versatile ingredient with so many applications that I might in future do further separate posts expanding on the ways you can use it and the effects it can help you achieve. For the moment here though I’ll give you a quick overview of the ingredient and focus on demonstrating four of the ways it can be used to great effect.

  • Simple Gelling (Gelee)
  • Agar Clarification (transparent clarifications of juices or stocks without loss of flavour)
  • Cold Oil Spherification (‘Caviar’)
  • Fluid Gels

Agar is available from www.Modernist-Chef.com

Agar Basics

Agar is derived from red algae (so like many ‘Molecular’ ingredients it has a natural source). Primarily in cooking it’s used as a gelling agent (its vegetarian so its sometimes used as a replacement for gelatin in recipes) or as a thickener. As I’ll go into bellow it can also be used to quickly and simply clarify liquids (to produce transparent stocks or juices, without loss of flavour) and to make small set spheres (‘caviar’) out of flavoured liquids. These are just a few, a sampler if you will, of the vast number of applications there are for this fantastic ingredient.

Agar also has the useful property that once gelled it won’t melt until heated up to 80-90C, so it can be used to make hot gelees and hot fluid gels for example (again there are many more applications where this heat resistant gelling is extremely useful)

Basics

  • For gelling Agar needs to be hydrated in a liquid and heated up around 90C in order for it to set as it cools.
  • When cooling Agar will set rapidly at around 35C
  • Once an Agar gel is been formed it won’t melt again until it reaches 80 -90C
  • Agar is typically used in concentrations from 0.2% to 2% (for most applications)

Simple Gelling

So, I’ll start with one of the simplest uses of Agar – Gelling.

Here’s a simple recipe that can be used as a template from which you change the flavours and desired yield etc easily.

Beetroot and Apple Gelee

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300g Beetroot juice
300g Apple juice
Pinch Salt
Note - the juices will be reduced to get 300g total liquid – they are only reduced to intensify their flavour so you could skip this step and just start with 300g total liquids.
2g Agar

First reduce the juices to intensify their flavour. - Mix the juices together with a pinch of salt and place in a pan to bring the liquid to a simmer. Gently reduce the liquid by half, intermittently skimming any froth that forms on the top of the juice. You should end up with 300g of total liquid.

Allow the reduced Beetroot and apple liquid to cool down to room temperature.

Whisk the 2g Agar into the 300g of cooled juice mixture and place it back on the heat. Bring to a simmer whilst stirring.

Pour out the Juice mixture into a wide plastic container and leave to cool and set. You could set the gelee in a mold or set it as a sheet to be cut to the desired shapes.

The mixture will set rapidly once it cools to around 35C


Agar Clarification

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(Clarified Orange Juice on the left, the original Juice on the right)

I think this is one of the most exciting things you can do using agar. Really quick, really effective, yet simple clarification of liquids. All you need to clarify juices or stocks is some Agar powder, a whisk, some cheesecloth and that’s about it (I’ll assume if your reading this you own a sauce-pan). Dave Arnold developed this technique and you can see his detailed blog on the technique
here.

One of the huge advantages of this is not only the clarity achieved and the fact that its vegetarian but also that its really quick, it can be done start to finish in less than an hour which is super quick compared to gelatin filtration which can take a couple of days!

So here I’m going go through the process of how to clarify orange juice as an example. This principle can be applied to other juices and stocks. One of the brilliant things about this technique is there is almost no loss of flavour. Blind Tasting the clarified juice next to the original juice its not easy to pick them apart.

Clarified Orange Juice.

750g Orange Juice
2g Agar (roughly 0.25% of the total weight – This is a tiny bit higher that Dave Arnold suggested using but it worked best for me – this might just be down to using different brands of Agar)

Pour 250g of the Orange Juice into a pan and whisk in the Agar. Bring this to a simmer whilst stirring.

Remove the pan from the heat and slowly pour the other 500g of room temperature Orange Juice into the hot Orange and Agar mix whilst stirring.

Then quickly pour this mixture into a bowl over an ice bath to set to a gel.

Once completely set gently break up the gelled Orange Juice with a whisk into ‘curds’ of gel.

Place the broken gel into a double layer of cheesecloth (or a tea towel). Lift this up over a coffee filter above a bowl where the clarified juice can collect and gently squeeze the cheesecloth. You should get a steady thin stream of clarified juice coming from the cheesecloth bundle.

And there you go, it’s that easy – you’ve now got clarified Orange Juice (or what ever you have decided to clarify).

Pretty Cool!


Cold Oil Spherification with Agar -

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Beetroot and Apple Caviar

Two liters vegetable oil chilled in the freezer
300g Beetroot juice
300g Apple juice
Pinch Salt
Note - the juices will be reduced to get 300g total liquid – they are only reduced to intensify their flavour so you could skip this step and just start with 300g total liquids.
3g Agar (1% of total liquids weight)

The start of this preparation is the same as for making a gel –

First reduce the juices to intensify their flavour. - Mix the juices together with a pinch of salt and place in a pan to bring the liquid to a simmer. Gently reduce the liquid by half, intermittently skimming any froth that forms on the top of the juice. You should end up with 300g of total liquid.

Allow the reduced Beetroot and apple liquid to cool down to room temperature.

Whisk the 3g Agar into the 300g of cooled juice mixture and place it back on the heat. Bring to a simmer whilst stirring.

Now – Pour the hot liquid into a squeeze bottle (or you can use a pipette, syringe or ‘Caviar box’ to form your spheres– if so pour the liquid into a bowl ready to use). Let the Liquid cool a little (but not enough that it begins to gel, - don’t let it get bellow 45C)

Pour the cold oil that’s been chilling in the freezer into a tall container; now drip the agar mix into the cold oil from a small height.

The droplets will gel as they are cooled by the oil and form into small ‘caviar’ spheres which sink to the bottom of the container.

Sieve out the set spheres and rinse under hot water. The ‘Caviar’ is now ready to serve.

Note – These spheres are set all the way through, for spheres, orbs and caviar with a liquid centre look and my post on Sodium Alginate and Reverse Spherification


Fluid gel

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To prepare an Agar fluid Gel first make and set a gel from your chosen flavoured liquid (following the directions for making an Agar gel above), 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 for a thickening by blending in a little xanthan gum.

In the accompanying photo I’ve made a Beetroot and Apple fluid gel by pureeing the simple Beetroot and Apple Gelee from the recipe above and thinning it with about two tablespoons of apple juice whilst blending.

Agar fluid gels can be served hot.


I hope all of this is interesting or useful.

I’m sure I’ll add more applications soon

Eddie x

Agar along with a range of modern ingredients and equipment is available from - www.Modernist-Chef.com