Cooking for Geeks: Real Science, Great Hacks, and Good Food (42 page)

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Authors: Jeff Potter

Tags: #COOKING / Methods / General

BOOK: Cooking for Geeks: Real Science, Great Hacks, and Good Food
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Caramelized White Chocolate

Inspired by Valrhona’s L’Ecole du Grand Chocolat

The extent to which the white chocolate is “roasted” will determine the color and flavor of the finished cream. Also, depending on the final application, the amount of gelatin needed will vary. Add more gelatin for a freestanding component, less for a cream that will be put into a shell or glass. Like many similar preparations, the blending phase is vital for achieving the ideal texture.

Caramelize 1 cup (170g) of white chocolate by placing the white chocolate in a sauté pan and heating it over medium-low heat, keeping a watchful eye on it. Stir occasionally, taking care to prevent any bits from turning darker than medium brown. Remove from heat. Add 1.5 teaspoons (10g) of glucose (or corn syrup).

In a separate pan, bring ½ cup (125g) whole milk to a boil. Stir in 2 to 3 sheets of bloomed gelatin (i.e., presoaked in cold water; you can use 2 teaspoons of powdered gelatin, although sheet gelatin is of higher quality). Remove from heat and slowly incorporate into the white chocolate mixture.

Add ¾ cup (175g) of heavy cream (36% fat) to the white chocolate mixture. Emulsify for a few minutes with an immersion blender. Transfer to a container and chill, allowing to crystallize, or dispense into desired forms.

Beurre Noisette Ice Cream

Create a batch of browned milk solids by reducing a quart of heavy cream in a saucepan over low heat, stirring occasionally. After a while — possibly as long as an hour — the heavy cream will separate into clarified butter and the milk solids. Save the clarified butter for some other purpose.

In a clean saucepan, measure out, whisk together to rehydrate the dry milk, and bring to a boil:

  • 1 quart (1000g) skim milk
  • 50g browned milk solids
  • ½ cup (60g) nonfat dry milk
  • ¾ cup (150g) granulated sugar
  • 60g glucose powder
  • 40g trimoline (inverted sugar syrup)

In a separate bowl, measure out and whisk together:

  • ¼ cup (50g) granulated sugar
  • 8g ice cream stabilizer
  • 200g egg yolks (yolks of about 3 large eggs)

Temper the hot milk into the yolk mixture by pouring a quarter of the hot liquid into the yolk mixture and whisking to combine. Add another quarter and whisk to combine. Pour the yolk mixture back into the saucepan, mix thoroughly, and return to low heat and cook, stirring, until slightly thickened (184°F / 84°C).

Remove from heat and whisk in:

  • ⅔ cup (150g) heavy cream

Chill the ice cream base in an ice-water bath, and then transfer to your fridge and allow to mature for at least 12 hours. Transfer the base to an ice cream maker and follow the manufacturer’s instructions.

RECIPES USED BY PERMISSION OF MICHAEL LAISKONIS

[
3
]
Well, safer — there’s no such thing as 100% safe.

Chapter 5. Air: Baking’s Key Variable

IF TIME AND TEMPERATURE ARE THE KEY VARIABLES IN COOKING, AIR IS THE KEY VARIABLE IN BAKING
. While few of us would list air as an ingredient, it’s critical to many foods. Most baked goods rely on air for their texture, flavor, and appearance. Baking powder and baking soda generate carbon dioxide, giving rise to cakes and quick breads. Air bubbles trapped in whisked egg whites lift soufflés, lighten meringues, and elevate angel food cakes. And yeast provides texture and adds complex flavors to bread and beer alike.

Unlike cooking, in which the chemical reactions are almost always in balance from the start — a chef rarely needs to tinker with ratios to get a protein to set — baking requires a well-balanced ratio of ingredients from the get-go to trigger the chemical reactions that create and trap air. Achieving this balance is often about precise measurements at the beginning, and unlike most meat and potato dishes, it’s virtually impossible to adjust the composition of baked goods as they cook. And as a further challenge, the error tolerances involved in baking are generally much tighter than those in cooking.

If you’re the meticulous type — methodical, enjoy precision, prefer a tidy environment — or the type of person who likes to express affection through giving food, you’ll probably enjoy baking more than cooking. On the other hand, if you have a wing-it-as-you-go, adapting-on-the-fly style, cooking is more likely to be your thing. But even if baking isn’t your thing, the engineering behind it can be fascinating, and plenty of applications in the “winging it” category can benefit from understanding the techniques discussed here.

In this chapter, we’ll start with a brief discussion of gluten and then cover the three primary methods of generating air in both savory and sweet applications. We’ll also discuss the ingredients associated with each of the three primary methods, giving examples and notes for how to work with them and why they work:

Biological
Yeast
Chemical
Baking powder and baking soda
Mechanical
Egg whites, egg yolks, sugar, whipped cream, and steam
Gluten

Light, fluffy foods need two things: air and something to trap that air. This might seem obvious, but without some way of holding on to air while cooking, baked goods would be flat. This is where gluten comes in.

Gluten is created when two proteins, glutenin and gliadin, come into contact and form what chemists call
crosslinks:
bonds between two molecules that hold them together. In the kitchen, this crosslinking is done by kneading doughs, and instead of talking about crosslinks, bakers speak of developing the gluten: the two proteins bind and then the resulting gluten molecules begin to stick together to form an elastic, stretchy membrane. The same stretchy, elastic property is also responsible for helping trap air bubbles in bread doughs: the gluten forms a 3D mesh that traps air generated by organisms such as yeast and chemicals like baking powder.

Regardless of the rising mechanism, understanding how to control gluten formation will vastly improve your baked goods. Do you want air bubbles to be trapped in the food, or do you want them to escape as the food is cooked? Breads and cakes rely heavily on air for texture, while cookies need less.

The easiest way to control the amount of gluten developed is to use ingredients that have more (or less) of the glutenin and gliadin proteins. Wheat, of course, is the most common source of gluten; rye and barley also have these proteins in small quantities. For practical purposes, though, wheat flour is the primary source of gluten.

Note

While rye has both glutenin and gliadin, it also contains substances that interfere with their ability to form gluten.

Gluten levels of various grains and common flours.

Note

Gluten levels will vary by both manufacturer and region. Since growing climate impacts gluten levels — colder weather yields higher-gluten wheat — flour in, say, France, won’t be identical to that grown in the U.S. Try working with a couple of different brands.

Here are three important things to keep in mind when working with gluten:

Use the appropriate type of flour
Different types of wheat flours have different levels of gluten. Cake flour is low in gluten; bread flour is high in gluten. (All-purpose flour should really be called “general compromise” flour: it just takes the middle ground, which is fine when gluten levels aren’t so important.) If you’re baking something that would suffer from the elastic texture brought about by gluten — that should have a crumbly texture such as a chocolate cake — use cake or pastry flours, and definitely avoid bread flour.
Fat inhibits gluten formation; water aids it
Fats interfere with the formation of gluten. This is why cookies, which have a lot of flour but also a lot of butter, still manage to crumble. And the opposite is true for water, which helps with gluten formation. The more water there is — up to a point, we’re not talking soup here — the more likely it is that glutenin and gliadin will bind.
Mechanical agitation and time develop gluten
Mechanical agitation (a.k.a. kneading) — physically ramming the glutenin and gliadin proteins together — increases the chances for those crosslinks to form and thus increases the amount of gluten in the food. Time, too, develops gluten, by giving the glutenin and gliadin the opportunity to eventually crosslink as the dough subtly moves.
Note

Flaky, crumbly baked goods = low levels of gluten.

Stretchy, elastic baked goods = high levels of gluten.

Flour = Starch + Gluten

Even though gluten is the key variable in wheat flour and baking, it’s worth stepping back and looking at what else is hanging out in flour:

  • Protein: 8–13%
  • Starch: 65–77%
  • Fiber: 3–12%
  • Water: ~12%
  • Fat: ~1%
  • Ash: ~1%

The two main compounds in flour are protein (primarily glutenin and gliadin) and starch. Warmer growing climates lead to lower levels of protein and higher levels of starch. Fiber is similar to starch in that both are carbohydrates — saccharides to biochemists — but our bodies don’t have a mechanism to digest all forms of saccharides; those that we can’t digest get classified as fiber (sometimes called nonstarch polysaccharides). As for ash, this is the broad term given to trace elements and minerals such as calcium, iron, and salt.

Gluten is the most important reason for using flour in baking. Try this simple experiment to separate out and “see” the gluten made by the proteins in flour.

Start with about 1 cup (120g) of bread flour in a bowl and add just enough water so that you can form a ball. Drop the ball of flour into a glass of water for an hour or so, long enough for it to absorb water and allow the gluten to develop.

After the ball has soaked, rinse the starches out by working the ball in your hands, kneading it with your fingers, under slowly running tap water. Keep working the ball until the water runs clear; only about a third of the original mass will be left. At this point, all the starch has washed away. Notice how the part of the flour that remains has a very elastic, stretchy quality to it: this is the gluten. You can drop the ball of gluten into a glass of rubbing alcohol to separate out the glutenin and gliadin proteins — the gliadin will form long, thin, sticky strands, and the glutenin will resemble something like tough rubber.

For comparison, try doing this with cake flour. You’ll find it almost impossible to hold on to the ball under the running tap water — there’s just not enough gluten present in cake flour to provide any structure to work with while washing away the starch molecules.

P.S. One food additive, transglutaminase, can be used to increase the gluten strength in baked goods by physically increasing the crosslinks within wheat gluten. See
Yeast Waffles
in
Chapter 6
for more.

When making breads, gluten impacts the texture not just with its stretchy, elastic quality, but also with its ability to trap and hold on to air. If you’re making a loaf of bread using whole wheat flour or grains low in gluten, adding some bread flour (start with 50% by weight) will result in a lighter loaf. You can also add gluten flour, which is wheat flour that has had bran and starch removed (yielding a 70%+ gluten content). Try making a loaf of whole wheat bread with 10% of the flour (by weight) replaced with gluten flour (sometimes called vital gluten flour).

In addition to managing texture, gluten can also be used directly as an ingredient. Consider the following recipe for seitan, a high-protein vegetarian ingredient often used as a substitute for chicken or beef in vegetarian cooking. Seitan is like tofu, in that it is a formed block or roll of proteins, in this case from wheat flour instead of soya beans.

Seitan

Mix together in a large bowl:

  • ¾ cup (175g) water
  • 2 tablespoons (35g) soy sauce
  • 1 teaspoon (5g) tomato paste
  • ½ teaspoon (5g) garlic paste, or 1 clove mashed and finely diced

Add, and use a spoon to mix to a thick, elastic dough:

  • 1 cup (160g) gluten flour (wheat flour that has had bran and starch removed)

Shape the dough into a log and place into a saucepan. Add:

  • 6 cups (1.5 liters) water
  • ½ cup (144g) soy sauce

Bring to a boil and then simmer for an hour. Allow to cool before using.

Notes

  • The gluten flour — also called
    vital wheat gluten —
    will take a few seconds to absorb the liquid. If you’re quick, you can form the dough into a more shapely log and roll it a few times on a cutting board. When cooking the seitan, if it comes out gluey, it wasn’t simmered long enough. If you’re going to fry the resulting seitan, this is okay, but otherwise you should return it to the simmering liquid and cook longer.
  • Not sure what to do with seitan? Try thinking of it like tofu: slice off pieces and pan-fry in oil; or shred the seitan, fry, and toss with a quick sweet-and-sour sauce and serve with rice.
Error Tolerances in Measuring

Measuring out too much (or not enough) butter when making mashed potatoes won’t lead to disaster. But with baking, the
error tolerance
in measurement — the amount you can be off by and still have acceptably good results — is much smaller.

How can you learn what measurements are important? Besides trying lots of experiments and keeping detailed notes, you can look at differences between recipes. (Look back at
Picking a Recipe
in
Chapter 1
for a discussion of comparing recipes.) By looking at the differences, you can also see what doesn’t matter so much.

Consider the ingredients for the following two pie dough recipes.

Joy of Cooking (8” / 20 cm pie)

Martha Stewart’s Pies & Tarts (10” / 25 cm pie)

100%

240g

flour

100%

300g

flour

60%

145g

shortening (Crisco)



(no shortening)

11.25%

27g

butter

76%

227g

butter

25%

59g

water

19.7%

59g

water

0.8%

2g

salt

2%

6g

salt



(no sugar)

2%

6g

sugar

The numbers in the first column are “baker’s percentages,” which normalize the quantities to the quantity of flour by weight; the second column gives the gram weights for one pie’s worth of dough.

Just comparing these two recipes, you can see that the ratio of flour to fats ranges from 1:0.71 to 1:0.76, and that a higher percentage of water is called for in the
Joy of Cooking
version.

However, butter isn’t the same thing as shortening; butter is about 15–17% water, whereas shortening is only fat. With this in mind, look at the recipes again: the Martha Stewart version has 76g of butter (per 100g of flour), for about 62g of fat; the pie dough with shortening has 60g of fat per 100g of flour. The quantity of water is also roughly equal between the two once the water present in the butter is factored in.

You won’t always find the ratios of ingredients between different recipes to be so close, but comparing recipes is a great way to learn more about cooking and a good way to determine which recipe to use when trying something new.

Note

There are two broad types of pie doughs: flaky and mealy. Working the fat into the flour until it is pea sized and using a bit more water will result in a flakier dough well suited to prebaked pie shells; working it until it has a cornmeal-like texture will result in a more water-resistant, mealy, crumbly dough, which makes it better suited for uses where it is filled with ingredients when baked.

Simple Pie Dough

Measure and combine all the ingredients for either the
Joy of Cooking
or the Martha Stewart recipe into a mixing bowl or the bowl of a food processor, cutting the butter into small cubes (½” / 1 cm). You should preferably use pastry flour, but AP flour is okay. Chill in the freezer for 15 to 30 minutes. Chilling the ingredients prevents the butter from melting, which would allow the water in the butter to interact with the gluten in the flour, resulting in a less flaky, more bread-like dough.

Pulse the ingredients in a food processor in one- to two-second bursts. Continue pulsing the dough until the ingredients are combined into a coarse sand-like or small pebble-like consistency. If you do not have a food processor, use a pastry blender, a couple of knives, or your fingers to crumble the fats into the flour. Make sure if you use your hands not to let the temperature of the dough rise much above room temperature.

Once the dough is at a coarse sand- or pebble-like consistency, dump the dough out onto a floured cutting board and press it into a round disc. Using a rolling pin, roll the dough out into a sheet, then fold it over on itself and roll it out again, repeating until the dough has been compressed and has enough structure that it can be transferred to a pie tin.

Note

Don’t have a rolling pin? A wine bottle will work in a pinch.

Prebaked Pie Shell

Some pies, such as lemon meringue pie (see
Lemon Meringue Pie
in
Chapter 6
), call for the pie shell to be prebaked. To prebake a pie shell (also called
blind baking
), roll out the dough and transfer it to your pie tin or mold. You’ll need to bake the pie with pie weights (no need to be fancy — beans or rice work perfectly); otherwise, the pie dough will slide down the edges and lose its shape. Once it’s baked enough to hold its shape, remove the pie weights so that the pie shell has a chance to crisp up and brown.

Set oven to 425°F / 220°C. Bake pie shell with pie weights for 15 minutes (use parchment paper to separate the pie weights from the dough, so that you can pick up the paper and remove the weights). Remove pie weights and bake for another 10 to 15 minutes, until shell is golden brown.

Note

I
hate
the taste of uncooked flour; it burns the back of the mouth. If you’re not sure whether your pie dough is done, err on the side of leaving it in longer.

When prebaking — also called “blind baking” — a pie shell, make sure to fill the shell with weights. Otherwise, the sides will collapse. Line the pie shell with a piece of parchment paper or foil and fill it with dried beans or rice.

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