Gels & Fluid Gels
Agar-Agar
Agar-agar is a sulphated polysaccharide extracted from red algae. It sets at 35–40°C and melts at 85°C — unlike gelatin (which sets at 15°C and melts at 35°C), agar sets and holds at room temperature, making it stable for warm presentations. Standard concentration: 0.5–2% agar by weight of liquid (0.5% for soft gels, 1.5% for firm sliceable gels). Application: dissolve in hot liquid above 90°C, pour into mould, allow to set. The result is a brittle, clean-setting gel that produces precise shapes.
The Fluid Gel
A fluid gel is made by allowing an agar solution to set fully into a solid gel, then breaking it down by blending at high speed. The result is a silky, pourable, smooth purée that behaves differently from both liquid and solid: it flows when force is applied (thixotropic) but holds its shape when at rest on a plate without weeping liquid. Used by Michelin-starred kitchens as an alternative to traditional sauces, fluid gels hold beautiful, clean shapes on a plate that classical reduced sauces cannot maintain.
Spherification
Direct Spherification
Direct spherification creates liquid-filled spheres by dropping a solution of sodium alginate (a seaweed-derived polysaccharide) into a bath of calcium chloride. The calcium ions instantly cross-link the alginate polymer chains at the surface of the droplet, forming a thin gel membrane around the liquid interior. The result is a sphere that bursts in the mouth, releasing the flavoured liquid. Used for mango caviar, olive oil pearls, and liquid cocktail spheres. Time-critical: the membrane continues to thicken the longer the sphere remains in the calcium bath.
Reverse Spherification
Dairy products and alcoholic liquids contain natural calcium that reacts immediately with alginate on contact, causing the exterior to gel before the sphere can form. Reverse spherification solves this: the liquid to be spherified is mixed with calcium lactate (the calcium source) and frozen into spheres. These spheres are then dropped into a sodium alginate bath, where the calcium inside the sphere forms the gel membrane from the inside out. The advantage: reverse spherification spheres have a thin, liquid-filled centre that never gels fully — they can be held for hours without becoming completely solid.
The Deconstructed Caprese
Serve a Caprese salad built entirely from modernist techniques: (1) a clear tomato consommé set into an agar fluid gel, (2) reverse-spherified liquid mozzarella "eggs", (3) a basil emulsion (air or fluid gel).
Success criteria: Fluid gel is pourable but holds shape on the plate without spreading. Mozzarella spheres burst cleanly in the mouth releasing liquid. Basil element is visually distinct. The overall presentation evokes Caprese but surprises the diner through unexpected textures.
Phase 2 Practice Exercises
12 exercises to build skill through direct application.
Agar Concentration Spectrum
Make agar gels at 0.3%, 0.6%, 1%, 1.5%, 2%. Cut cross-sections and assess firmness, clarity, and texture.
- Scientific precision
- Technique mastery
- Creative application
Agar Fluid Gel
Make a fluid gel from tomato water. Test pourability on a cold plate vs a warm plate.
- Scientific precision
- Technique mastery
- Creative application
Direct Spherification Basics
Make mango juice spheres using 0.5% sodium alginate and 0.5% calcium chloride bath.
- Scientific precision
- Technique mastery
- Creative application
Sphere Formation Timing
Drop identical alginate spheres and retrieve at 15s, 30s, 1min, 2min intervals. Compare membrane thickness.
- Scientific precision
- Technique mastery
- Creative application
Reverse Spherification Setup
Make reverse spherification yoghurt spheres using calcium lactate.
- Scientific precision
- Technique mastery
- Creative application
Liquid Mozzarella Spheres
Make a whey and cream solution with calcium lactate. Reverse spherify into mozzarella-like spheres.
- Scientific precision
- Technique mastery
- Creative application
Tomato Consommé Clarification
Clarify tomato water using a gelatin raft method to produce crystal-clear tomato liquid.
- Scientific precision
- Technique mastery
- Creative application
Basil Oil
Blanch and shock basil, then blend with neutral oil. Pass through muslin for a clear green oil.
- Scientific precision
- Technique mastery
- Creative application
Alginate Bath Troubleshooting
Diagnose and fix common spherification failures: tails, uneven membranes, cloudy spheres.
- Scientific precision
- Technique mastery
- Creative application
Xanthan Gum Sauce
Thicken a cold sauce with 0.1% xanthan gum. Assess the texture and behaviour under shear.
- Scientific precision
- Technique mastery
- Creative application
Caviar Service
Practice making 40 consistent alginate caviar pearls using a squeeze bottle or pipette.
- Scientific precision
- Technique mastery
- Creative application
Full Caprese Milestone
Execute the complete Deconstructed Caprese. Photograph and self-evaluate.
- Scientific precision
- Technique mastery
- Creative application