Cooking for Geeks: Real Science, Great Hacks, and Good Food (61 page)
Read Cooking for Geeks: Real Science, Great Hacks, and Good Food Online
Authors: Jeff Potter
Tags: #COOKING / Methods / General
At a high level, making gels is about transforming liquids into solids. In addition to creating gels, though, modern food additives can be used to alter other properties of foods, and another area of play in the modernist kitchen is that of melting. How can we make things change state in unexpected ways?
Methylcellulose has the unusual property of getting thicker when heated (
thermo-gelling
in chem-speak). Take jam: when heated, it loses its gel structure (the pectin melts), causing it to flow out of things like jam-filled pastries. Adding methylcellulose prevents this by causing the jam to “gel” into a solid under heat. And since methylcellulose is thermoreversible, upon cooling after baking, the jam returns to its normal consistency.
Hollywood uses methylcellulose to make slime. Add a bit of yellow and green food dye, and you’ve got yourself
Ghostbusters
-style slime. To get good consistency, whisk it vigorously to trap air bubbles into the mixture.
Methylcellulose has been used in some modernist cuisine dishes for its thermo-gelling effects. One famous example is “Hot Ice Cream” in which the “ice” cream is actually hot cream that’s been set with methylcellulose. As it cools to room temperature, it melts.
Instructions for use. |
Uses. |
Note Methylcellulose increases surface tension — well, actually, “interfacial tension” because “surface” refers to a two-dimensional shape — which is why it works as an emulsifier. |
Origin and chemistry. |
When cold (on left), water molecules are able to form water clusters around the methylcellulose molecule. With sufficient heat — around 122°F / 50°C — the water clusters are destroyed and the methylcellulose is able to form crosslinks, resulting in a stable gel at higher temperatures.
These marshmallows remain firm when hot, but melt as they cool. This recipe is adapted from a recipe by Linda Anctil (
http://www.playingwithfireandwater.com
).
In a saucepan, bring to a boil:
- 2⅛ cups (500g) water
- 1 cup (200g) sugar
Let cool, and then whisk in:
- 10g methylcellulose (use a scale to ensure an accurate measurement)
- 1 teaspoon (5g) vanilla extract
Let rest in fridge until thick, around two hours. Once thick, whisk until light and foamy. Transfer to a 9” × 9” / 20 cm × 20 cm baking pan lined with parchment paper. Bake for five to eight minutes at 300°F / 150°C, until set. The marshmallows should feel dry to the touch and not at all sticky. Remove from oven, cut into desired shapes, and coat with powdered sugar.
Two marshmallows on a plate of powdered sugar.
Two marshmallows after being coated with powdered sugar while still hot.
Same marshmallows after cooling for a few minutes.
When working with gels, you can quickly cool the hot liquid by whisking it while running cold water over the outside of the pan. The water will flow along the bottom of the pan.
Maltodextrin — a starch — dissolves in water, but not fat. In manufacturing, it’s spray-dried and agglomerated, which creates a powder that’s very porous on the microscopic level. Because of this structure, maltodextrin is able soak up fatty substances (they won’t cause it to dissolve), making maltodextrin useful for working with fats when designing food. It also absorbs water, so is used as an emulsifier and thickener, as well as a fat substitute: once hydrated, it literally sticks around, mimicking the viscosity and texture of fats.
Since it comes as a white powder, you can also use maltodextrin to turn fatty liquids and solids such as olive oil and peanut butter into powder. Because maltodextrin traps oils but dissolves in water, the resulting powder dissolves in your mouth, effectively “melting” back into the original ingredient and releasing its flavor. Since maltodextrin itself is generally flavorless (only slightly sweet), it does not substantially alter the flavor of the product that is being “powderized.”
In addition to the novelty and surprise of, say, a powder dusting on top of fish melting into olive oil in your mouth, powders can carry flavors over into applications that require the ingredients to be effectively “dry.” Think of chocolate truffles rolled in chopped nuts: in addition to providing flavor and texture contrast, the chopped nuts provide a convenient “wrapper” around the chocolate to allow you to pick up the truffle and eat it, without the chocolate ganache melting on to your fingers. Powdered products can be used to coat the outsides of foods in much the same way that chopped nuts are used to coat the outside of truffles.
Instructions for use. |
Uses. |
Origin and chemistry. When it comes to understanding how maltodextrin soaks up oils, imagine it being like sand at the beach. The sand doesn’t actually bond with the water, but it’s still wicking up the liquid in the space between the granules due to capillary action. When working with either sand or maltodextrin, with the right amount of liquid, the powder clumps up and becomes workable. Because maltodextrin is water soluble, however, water would dissolve the starch granules. And, luckily, maltodextrin can soak up a lot more oil per volume than sand can soak up water, making it useful for conveying flavors in a nonliquid form. |
Whisking any fat such as browned butter (upper left) with maltodextrin (center right) creates a powdered form (bottom) that can be used to create a surprising texture as the powder “melts” back into browned butter when placed in the mouth. Try using this browned butter powder as a garnish on top of or alongside fish, or making a version with peanut butter and sprinkling on desserts.
In a skillet, melt:
- 4 tablespoons (60g) salted butter
Once melted, continue to heat until all the water has boiled off. The butter solids will start to brown. Once the butter has completely browned and achieved a nutty, toasted aroma, remove from heat and allow to cool for a minute or two.
In a small mixing bowl, measure out:
- ½ cup (40g) maltodextrin
While whisking the maltodextrin, slowly dribble in the browned butter until a wet sand–like consistency is reached.
Notes
- Stir slowly at the beginning because maltodextrin is light and will easily aerosolize. The ratio between maltodextrin and the food will vary. If your result is more like toothpaste, add more maltodextrin.
- If the resulting powder is still too clumpy, you might be able to dry it carefully by transferring the powder to a frying pan and applying low heat for a few minutes. This will help dry out any dampness present from room humidity. It will also partially cook the food item, which might not work for powders containing items such as white chocolate.
- For a finer texture, try passing the powder through a sieve or strainer using the back of a spoon.
- Try adding a bit of lemon juice to the brown butter, after it has cooled but before mixing it with the maltodextrin.
- Additional flavors to try: peanut butter, almond butter, coconut oil (virgin/unrefined), caramel, white chocolate, Nutella, olive oil, foie gras, bacon fat (cook some bacon and save the fat drippings — this is called
rendering
). You don’t need to heat the fats first, but it might take a bit of working to get the maltodextrin to combine. For liquid fats (olive oil), you will need to use roughly 2 parts maltodextrin to 1 part fat: 50g olive oil, 100g maltodextrin.
