Cooking for Geeks: Real Science, Great Hacks, and Good Food (70 page)
Read Cooking for Geeks: Real Science, Great Hacks, and Good Food Online
Authors: Jeff Potter
Tags: #COOKING / Methods / General
The UK magazine
Intelligent Life
did a piece on Dave Arnold, including the “stupid extra length” he went to to make a perfect gin and tonic. Dave explains:
It was called the $10,000 gin and tonic because there was all this equipment and time, and rotary evaporation, and the PSI measured carefully, and clarifying juices, etc. I was redistilling lime essence to create a clear lime juice so that I could add that to my quinine simple syrup and gin and get the water level exactly where I wanted it and carbonate it. The reason you want it clear is because gin and tonic should be clear, and should have enough bubbles, and the right alcohol content. So I was able to break out every single variable and recombine them exactly the way I wanted.
The idea of the original recipe,
Bottle Strength G ’n T
, was to produce a gin and tonic shot at bottle strength (80 proof). To do it, we distilled lime juice and gin to capture the fresh volatiles from the juice and increase the proof of the gin. We then added acids back to the distillate to recreate the flavor of the lime juice, along with sugar and quinine, the bitter part of tonic water. Why all this? Adding sugar, acid, etc. lowered the proof of the gin. If we wanted to serve bottle-strength gin and tonic shots, we had to raise the initial proof. Plus, distilling the lime volatiles gave us a perfectly clear drink that carbonates well (pulp is a carbonation killer). We no longer serve this version, because it only tastes good at around 0°F / –18° C. Served any warmer than 5°F / –15° C, and it tastes unbalanced; any colder than –9°F / –23° C, and it is painful going down. It was hard to get people to drink quickly enough, when the shots were at the right temperature.
This same technique, when watered down to 15–20% alcohol by volume, produces our perfect G ’n T, and it’s much easier to do. I use what we call
simple agar clarification
on lime juice. I can do it in 20 minutes on a camp stove and I don’t need the high-end equipment to make it. It’s back to a normal cost in terms of equipment, except for a carbonation rig. The good news is that it’s very inexpensive to get a real carbonation rig at home. The whole carbonation rig costs well under $200. A single 20-pound tank of CO
2
costs about $20 to refill, and it makes 200 to 400 gallons of seltzer or liquor. Everyone should have one in their house. Everyone.
Clarified lime juice.
Squeeze the juice from 10 limes into a container, running through a sieve to remove pulp. Weigh the juice; it should be around 500g. Set aside.
In a pan, create an agar gel using water and agar. Measure out a quarter of the amount of lime juice in water, roughly 125g of water, and create a 10% agar gel, around 12g (this will result in a 2.0% concentration once mixed with the lime juice). Once the agar has melted, remove from heat and pour the water-agar mixture into the container with the lime juice and let it rest for half hour or so, until set.
Once the lime gel has set, use a whisk to break the gel into pieces. Take the whisk and make zigzag slashing cuts; don’t actually whisk the gel.
Transfer the broken gel to a cheesecloth (real cheesecloth, not the loose mesh stuff) or towel. Fold the cloth up into a ball.
Hold the balled cloth above a coffee filter and squeeze it with your other hand, massaging it to force out as much liquid as possible. (The coffee filter will catch any small chunks of agar that happen to leak through).
Simple syrup with quinine.
Create a simple syrup (2 parts sugar, 1 part water), then add diluted quinine sulfate. Be careful! Quinine in anything other than minute quantities is poisonous! The legal limit is 83 parts per million of quinine, which is 0.083 grams of quinine sulfate per liter of liquid. You will need considerably less than this. Quinine goes from pleasantly bitter to extraordinarily bitter rather quickly. Make a solution of 1g quinine sulfate in 500 ml of water (or gin) and use no more than 40 ml of this solution per liter of finished product and you will be okay. You will probably like less than half that amount.
To assemble:
- 4 oz gin
- 2 oz clarified lime juice
- Simple syrup with quinine to taste
- Salt to taste
Chill in freezer. Carbonate to 40 PSI.
We’re all familiar with whipped cream in a can. A
cream whipper
is a reusable version of the can, without the cream, that you fill with cream or whatever else you like. They’re a simple yet clever design: pour your contents into the container, screw on the lid, and pressurize using a small, bullet-like cartridge that provides either nitrous oxide or carbon dioxide to the can through a one-way valve.
Cream whippers take their name from their primary purpose: making whipped cream. With a whipper, you can control the quality of the ingredients and the amount of sugar used. Fill it up, store in the fridge, and there’s no functional difference between a whipper and the more familiar whipped cream in a can.
The obvious extension is to create flavored whipped cream. Toss some orange zest and maybe a bit of vanilla sugar into a pint of organic cream, and spray away. Try tea-infused cream: steep some Earl Gray in cream and transfer it to the whipper, or go smoky and use Lapsang Souchong. Just remember to strain the tea leaves out before filling the canister of the whipper! You can also spike the cream — make amaretto cream to go on your coffee with 4 parts heavy cream, 2 parts amaretto liqueur, and 1 part powdered sugar.
But the real fun with cream whippers (besides whipped cream fights) is passing other liquids through them. You can whip any liquid or mixture that has the ability to hold air — that is, anything that can be turned into a foam (sometimes called an
espuma
in menu speak), including foamed “waters” flavored like carrots or desserts like chocolate mousse. You can even put pancake batter in a cream whipper (hence the whole “pancakes in a can” thing). Because the contents are ejected under pressure, small, pressurized bubbles come along for the ride and expand, leading to mechanical injection of air into the liquid. This is why cream turns into whipped cream, although the foam that’s generated isn’t as stable as manually whisked whipped cream.
The most common brand of cream whipper used in the food industry is made by iSi (it’s not uncommon to hear a cream whipper simply called an “iSi”). Regardless of manufacturer, basic models run $40 to $60 dollars; cartridges are about $0.50 each in bulk.
Don’t use chargers made for BB guns. They aren’t food grade.
This might be more than you want to spend upfront for just whipped cream, but if you’re a regular user of the canned stuff, the long-term savings alone will make it worthwhile. If you want to play around with textures and flavors in the kitchen, it’s downright cheap.
Cream whippers also come in a “thermal” style (i.e., built like a Thermos) that’s useful for keeping contents cold if you’re working onsite. The thermal versions can’t be used in water baths, though, making it harder to do hot foams or to partially poach the contents à la sous vide for egg-based custards.
A few things to keep in mind when working with a whipper:
- Make sure the gasket is properly seated and the threads on the lid are clean when screwing on the lid, unless you want chocolate cake batter, cream, or pancake mix sprayed 10 feet in a random direction.
- Always run your liquid through a strainer (~500 micron is fine) to remove any particulates that might clog the nozzle. You can skip straining things like plain cream, of course.
- When working with heavier batters, you can double-pressurize the canister. After pressurizing with one cartridge, remove it and pressurize with a second one. You’ll find that the pressure decreases as you run through the contents, because the airspace in the whipper increases as the contents are ejected.
- If your liquids fail to foam correctly, try adding some gelatin, which provides structure. If you don’t mind taking a shortcut, try using flavored Jell-O.
You can also use a whipper as a source of pressure. One technique uses an adaptor from McMaster-Carr to connect the spray nozzle of the whipper to a length of plastic tubing. Fill the tubing with a hot liquid with agar or other gelling agent, let it set, and use the whipper to force-eject the “noodle.”
Another thing to try is using a CO
2
cartridge to create “whipper fizzy fruit” — fruit that has been carbonated, giving it a fizzy texture. Try popping grapes, strawberries, or sliced fruit such as apples and pears into the canister and pressurizing it. Let rest for an hour, depressurize, and remove fruit. Not exactly haute cuisine, but fun to do as a party trick. Fizzy raspberries make a great basis for a mixed drink.
This creates a very light chocolate mousse, almost the complete opposite of the dense chocolate mousse based on agar from
Chapter 6
(see
Chocolate Panna Cotta
).
Heat to a temperature hot enough to melt chocolate (130°F / 55°C):
- 1 cup (250g) heavy cream
Remove from heat and whisk in to melt:
- 6 tablespoons (60g) bittersweet chocolate
- ¼ teaspoon (0.6g) cinnamon
Transfer to whipper canister and chill. Make sure the liquid is completely cold — fridge temp — before using. Otherwise, the cream won’t whip.
Pressurize and dispense into serving glasses or on a plate, as desired.
Notes
- You can dump the canister in a plastic container filled with half ice, half water to chill it quickly.
- The cream really does need to be completely chilled. If it’s not, instead of getting a light, airy chocolate mousse foam, you’ll get a jet of chocolate-flavored heavy cream.
This egg foam is something like a whipped mayonnaise, but incredibly light. Try it with steak and fries. This recipe is based on a recipe by Alex and Aki of
http://www.ideasonfood.com
fame
.
Measure out into a bowl:
- 4 large (240g) eggs
- 5 tablespoons (75g) heavy cream
- ½ teaspoon (2g) salt
- ½ teaspoon (2g) sriracha sauce
Using an immersion blender, thoroughly purée the ingredients. Strain into a nonthermal whipper and screw lid on, but do not pressurize. Place whipper in a water bath at 158°F / 70°C and cook until the mixture is partially curdled, around 60 to 90 minutes. Remove from bath, check that eggs are just partially set, and pressurize. Dispense into small bowls and garnish, or use as a component in a dish.
Notes
Try using the small strainer from a loose-leaf teapot when filtering liquids — it’s easier to hold above the container while pouring in the mixture.
In a microwave-safe bowl, melt:
- 4 oz (113g) chocolate (bittersweet preferably)
Add and thoroughly whisk together:
- 4 large (240g) eggs
- 6 tablespoons (80g) sugar
- 3 tablespoons (25g) flour
Pass the mixture through a strainer to remove any lumps and to filter out the chalazaes (the little white strands that attach the yolk to the egg white). Transfer to whipper and pressurize.
Spray mixture into a greased glass, ramekin, or whatever microwave-safe container you will cook it in, leaving at least the top third of the container empty. The first time you do this, I recommend using a clear glass so that you can see the cake rise and fall as it cooks.
Microwave for 30 seconds or until the foam has set. Flip onto a plate and dust with powdered sugar.
Powdered sugar is the bacon of the pastry world. It goes well with almost everything and is great for covering up things like tears or holes — in this case, covering up the Nutella filling.
For better-tasting results, try adding Nutella or Fluff: spray a thin layer of cake batter, drop a spoonful of filling into the center, and then spray more cake batter on top of and around the filling.
After cooking, cover in chocolate and do a small loopy white icing thing on the top, and you’ve got something close to commercial cream-filled cupcakes.
Notes
- Try spraying a thin layer of the batter onto a plate and cooking that. Peel it off the plate, coat the top with a layer of jam or whipped cream, and roll it up to create a log-shaped chocolate treat.
- To be fair, you can do a close approximation without using a whipper. Search online for “microwave chocolate cake.” I find that the iSi Whipper version produces a more uniform, spongier cake, though.
Unbaked: nonwhipped (left) and whipped (right).
Baked: nonwhipped (left) and whipped (right).