Modernist Cooking Made Easy (11 page)

Thermoreversibility

If a gel can get set and then melt, like Jell-O melting on a warm day, then it is considered thermoreversible. If the gel cannot be unset, like a soufflé, then it is considered thermo-irreversible. Most thermoreversible gels can be set and unset many times without a loss in gelling strength.

Shear Thinning or Thixotropy
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Both of these terms refer to the ability to act like a set gel when at rest and to flow when agitated, as through whisking, stirring, or blending. This can be a very nice effect, especially for sauces you want to coat food with or for purees that need extra body. This is a common property in fluid or sheared gels.

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Even though there are lots of different kinds of gels, most of the time a similar process is used to create them. For instructions for a specific ingredient you can see the chapter for it from the section on Ingredients.

Dispersion

Typically, the first step is to disperse the gelling agent in the liquid you want to gel. Dispersion is simply the act of evenly distributing the ingredient throughout the liquid. This will ensure a gel of even strength.

A good example of dispersion gone wrong is when you try to add flour to a hot liquid. Instead of a smooth gravy you get lumps where the flour gelled together. Proper dispersion of the flour, usually using a water slurry or fat-based roux, eliminates the lumps.

Depending on the ingredient you may have to use a hot, cold, acidic, or other liquid for proper dispersion. For some ingredients a whisk or spoon will work fine, others will need the stronger shearing forces of an immersion or standing blender.

One exception to the rule of dispersing first is gelatin. It is hydrated, or “bloomed” first, before being dispersed.

Hydration

Once the gelling agent has been fully dispersed it needs to hydrate. Hydration is basically the process of absorbing water, or another liquid, and swelling. This absorption of liquid, in conjunction with other processes, causes the thickening of the mixture, creating a molecular mesh that traps water
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Depending on the gelling agent and the liquid being used, hydration will occur at different temperatures and over different time frames. Many ingredients will need to be heated for hydration to occur, like flour and agar.

Gelling or Setting

The final stage is when the liquid actually gels. Many gelling agents will gel at a specific temperature, others may gel at any temperature. This process can take anywhere from a few minutes to many hours.

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ONSIDERATIONS

Gelling Raw Ingredients

Sometimes you do not want to bring the liquid you are gelling to a boil. In order to hydrate a gelling agent that must be heated you have two options.

You can disperse and hydrate the gelling agent in a small amount of the liquid and blend the rest of the liquid into it after hydration. You can also disperse and hydrate the gelling agent in water and blend the liquid into that.

Either way, the temperature will drop quickly and some gelling agents, such as agar, will begin to set faster than usual. Warming up the liquid as much as you can is advised for better dispersion once the gelling agent has hydrated.

Water Impurities

Due to the way many of these ingredients create their molecular webs the chemicals in your water can affect the gelling power of your dishes. If you have water that has a high mineral content, or are consistently having trouble with your gels it might be worth experimenting with filtered, spring, or distilled water. It won’t always fix the problem but it will at least eliminate one variable from the equation.

Hot vs Cold

Different gelling agents create gels that can withstand a wide variety of temperatures. Be sure to pick a gelling ingredient that meets the needs of the dish you are preparing. For instance, gelatin melts just above room temperature so it cannot be used with hot preparations while agar gels can be heated up to around 80ºC / 176ºF before it melts.

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ELLING
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NGREDIENTS

There are many different gelling ingredients. This book focuses on several different modernist ingredients that we found to be easily accessible and simple to use. Below is a short description of the gelling agents we cover in depth. For specific uses of each one, as well as more recipes, please see its chapter in the Ingredients section.

Agar

Agar creates brittle gels and it must be brought to a boil to hydrate. It sets at room temperature and can be heated to 80ºC / 175ºF before melting. You can also add locust bean gum to agar gels to make them more elastic.

Carrageenan: Iota

Iota carrageenan creates elastic gels and is especially effective with dairy products. It is often used in custards or puddings.

It must be heated to hydrate then cooled to set the gel. Once gelled it can be reheated several degrees above the gelling temperature before melting.

Carrageenan: Kappa

Kappa carrageenan can be used to create firm, brittle gels and is especially effective at gelling dairy-based liquids. To gel, the liquid must contain either calcium or potassium that is free to bind with the kappa carrageenan.

It must be heated to hydrate then cooled to set the gel. Once gelled it can be reheated several degrees above the gelling temperature before melting.

Gelatin

Gelatin forms elastic gels that can’t be raised much above room temperature. Gelatin has to be dispersed in hot liquid and sets at room temperature or below.

Methylcellulose

Methylcellulose has the uncommon ability to gel as it heats, and melt as it cools. There are many different types of methylcellulose available for a variety of uses.

Sodium Alginate

Sodium alginate is commonly used in spherification because of its ability to gel in the presence of calcium ions. It can be dispersed and hydrated at almost any temperature and the gels are very heat tolerant.

Other Gelling Agents

There are many other gelling agents we do not cover in depth but can be found in the Other Ingredients chapter such as lambda carrageenan, gellan, and pectin.

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EL

This is a nice and basic recipe for agar gels. It is brittle and has a medium firmness to it. I use pineapple juice here but almost any fruit juice will work great.

For the mold you can just use a tupperware container or get more creative and use one of the mold shapes we cover in the following section of this chapter.

Tools Needed

Agar

Immersion blender

A scale with small gram measurements

Small flat bottom mold or other container

Ingredients

300 grams pineapple juice

3 grams agar, 1.0%

Get your molds out and set up. The gel will set quickly so having them ready is crucial.

Add 150 grams of the pineapple juice to a small pot. Add the agar and blend well with an immersion blender. Bring to a boil and let simmer for 3 to 5 minutes. Add the remaining pineapple juice and blend well with the immersion blender.

Pour the liquid into the mold and let cool at room temperature. You can place the mold in an ice bath or in the refrigerator for quicker setting. Once it cools you can continue on or place it covered in the refrigerator overnight.

Once you are ready to use the gel, turn it out onto a cutting board. Cut the gel into the shapes you desire using a knife or other cutting implement.

Hold covered in the refrigerator or at room temperature until ready to serve. The cubes will remain a gel as long as they stay below 80°C / 176°F. They will last covered in the refrigerator for a few days but will slowly dry out over time.

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ELS

These elastic agar gels are great as a snack or served as a garnish on pork chops. For a garnish I like to cut them into thin ribbons or small cubes.

For the mold you can just use a tupperware container or get more creative and use one of the mold shapes we cover in the next section of this chapter.

Tools Needed

Agar

Locust bean gum

Immersion blender

A scale with small gram measurements

Small flat bottom mold or other container

Ingredients

300 grams apple cider

1.5 grams agar, 0.5%

0.75 grams locust bean gum, 0.25%

Get your molds out and set up. The gel will set quickly so having them ready is crucial.

Add the apple cider to a small pot. Sprinkle in the agar and locust bean gum and blend well with an immersion blender. Bring to a boil and let simmer for 3 to 5 minutes while stirring occasionally.

Pour the liquid into the mold and let cool at room temperature. You can place the mold in an ice bath or in the refrigerator for quicker setting. Once it cools you can continue on or place it covered in the refrigerator overnight.

Once you are ready to use the gel, turn it out onto a cutting board. Cut the gel into the shapes you desire using a knife or other cutting implement.

Hold covered in the refrigerator or at room temperature until ready to serve. The cubes will remain a gel as long as they stay below 80°C / 176°F. They will last covered in the refrigerator for a few days but will slowly dry out over time.

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ERBED
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USTARD

You can infuse milk or cream with many different flavors before gelling them with iota carrageenan. In this recipe I combine rosemary, thyme, and sage to create an herbal custard. It is great as an accompaniment with steak or roasted chicken.

Tools Needed

Iota carrageenan

Immersion blender

Molds or setting containers

Chinois

A scale with small gram measurements

Ingredients

1 teaspoon whole coriander

1 teaspoon whole peppercorns

½ teaspoon whole cumin

½ teaspoon whole cloves

500 grams milk, about 2 cups

3 tablespoons rosemary

2 tablespoons thyme

2 tablespoons sage

Salt and pepper

5 grams iota carrageenan, 1%

Place a small pan over medium heat. Add the coriander, peppercorns, cumin, and cloves and toast until fragrant, just a few minutes.

Pour the milk into a pot and add the herbs and toasted spices. Heat over medium-high heat, stirring occasionally to prevent scorching, and bring to a boil. Once it boils, blend with an immersion blender until slightly pureed. Remove from the heat and let steep for 20 to 30 minutes. Salt and pepper to taste.

Strain the milk, preferably through a chinois for the finest texture. Add the iota carrageenan and blend well with an immersion blender. Bring to a boil and blend for 30 to 60 seconds. Remove from the heat and pour into molds.

Let cool at room temperature, or in an ice bath, then place in the refrigerator to finish setting.

Once fully set the gel can be turned out and cut into any shapes desired. The gel should last for several days covered in the refrigerator.

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