Marvelous Mixtures Part 4, Plain Old Popcorn

So this entry is a tribute to one of my very good friends (shout out Kara) who had a very interesting experience trying to make popcorn without an air popper or a microwave. It is also one in a series of posts about how to eat foods without artificial preservatives (see jam and hamburger helper). My goal for this summer is to cut my artificial preservatives down to an absolute minimum. And that makes snack food a little tricky. But, popcorn from something other than a bag is actually pretty good and low calorie, so it has become a staple in my snack food diet, and a mystery. How does popcorn work?

Popcorn is a seed. There are three main things in a popcorn kernel, the shell, the starches inside (to feed an eventual popcorn plant), and some water. Before you heat it everything is contained inside the hard shell. But, as you heat the kernels the water turns to steam (a gas) and the volume remains constant while the temperature increases, increasing the pressure (remember P*V=n*R*T?). Eventually the pressure is just too much for the little shell and BOOM, it pops open like a balloon with too much air in it. The starches stretch out and form a solid network through covalent bonds, trapping air as it goes (see cornstarch crystal). When air is dissolved in a solid it is a colloid known as solid foam, like styrofoam.

Because of how it works popcorn will not pop if 1) the popcorn doesn't get hot enough (which is why you cook it in hot oil), 2) the popcorn dries out, or 3) if the popcorn shell has a crack or hole in it that releases the steam, lowering the pressure.

A microwave works by sending out a frequency in the electromagnetic spectrum (like the light we see, the UV rays that hurt our skin, or the radio waves that make beautiful music). The frequency it uses is a very special one that makes the bonds in water jiggle and dance (resonance). Temperature is a measure of how fast the molecules are moving, so as they dance more, the temperature goes up and eventually the dance so far away from each other the create steam, increased pressure, and eventually a popcorn explosion.

If you don't have a microwave you have to use a lower tech version to make the water dance, heat transfer. As molecules from something warmer, like hot oil, hit slower moving molecules from something colder, like the water in the popcorn, a little bit of the speed is transfered. Making the hot thing colder and the cold thing hotter until they are the same temperature. It's like when you play pool. When one pool ball hits another the first one slows down and the second one starts moving or speeds up. Molecules act the same way.

This is not really a recipe, but directions for how to make popcorn yourself without any special gadgets. Enjoy!

Popcorn

Ingredients

2 Tablespoons oil

1/4 cup unpopped popcorn kernels

Toppings of your choice

Place oil in a sauce pan with a single kernel of popcorn. Heat on medium until the kernel pops. Add remaining popcorn kernels and cover with a lid. Heat, shaking frequently, until the popping slows to 2-3 seconds between each pop. Remove from heat, cover in toppings and enjoy.

Marvelous Mixtures Part 3, Wonderful Whipped Cream (and the stuff that goes under it)

So, I know it has been a long time since you've heard from me, and even longer since you eaten with me. Sorry about that. Graduation is hard work. Traveling across 10 states to get home is even harder. Word to the wise. Visit Nashville, it's HEAVEN. Oh, and drink the sweet tea.

So far when it comes to mixtures we've talked about sol and gel. To recap: three phases (solid, liquid, and gas), they can mix together. Sometimes the mix really really well and make a colloid. One of these colloids is created when a gas is dissolved in a liquid, it is called a foam. Not to be confused with styrofoam of course. Whipped cream is an excellent example. As you whip heavy cream two things happen. 1) air bubbles get trapped inside and 2) the proteins and fat in the cream create a network of bonds that keeps them there. Simple enough.

I have suddenly found myself transported back a few weeks produce-wise. Here in Minnesota the farmer's markets are just starting to open up. Which of course means berry season. Unfortuanately it is still a little early for blackberries in this part of the country, so thank GOD for California. This blackberry cobbler recipe is from Pioneer Woman (thepioneerwoman.com/cooking) and it is amazing. The homemade sweeten whipped cream is a must (though the store bought stuff will work too if you are in a crunch). If you can't find fresh berries where you are from, frozen works too. Try other flavors (raspberry, cherry), let your imagination run wild.

Blackberry Cobbler w/ Homemade Whipped Cream

Cobbler

Ingredients

1/4 pound (1 stick) butter, melted

1 1/4 cups plus 2 Tablespoons sugar (divided)

1 cup flour

1 1/2 teaspoon baking powder

1/4 teaspoon salt

1 cup milk

2 cups blackberries (preferably fresh, but frozen will work)

Preheat the over to 350 degrees. Grease a 3-quart baking dish with butter. Whisk together the flour, baking powder, and salt. In a medium bowl, whisk 1 cup of sugar with the dry ingredients and milk. Whisk in the melted butter. Rinse the blackberries and pat them dry. Pour the batter into the baking dish. Sprinkle the blackberries evenly over the top of the batter. Sprinkle 1/4 cup sugar over the blackberries. Bake for 50 minutes. Sprinkle the last 2 tablespoons of sugar over the cobbler and bake for 10 more minutes or until golden brown and bubbly. Serve with homemade whipped cream.

Whipped Cream

Ingredients

1 cup heavy whipping cream

1/4 cup sugar

1 teaspoon vanilla

Whip the cream until almost stiff. Add sugar and vanilla, and whip until cream holds stiff peaks.

Marvelous Mixtures Part 2, Perfect Panna Cotta

So, this weekend my kitchen was a little crazy. I had a bunch of friends over for homemade pizza, cannoli, and panna cotta. And it got me to thinking about one of the biggest mysteries in cooking, gelatin. I mean really. What phase of matter is Jell-O? And what makes it work?

To answer the first question, substances come in three phases of matter, solid, liquid, and gas. Solids are substances that are a set shape and volume because the molecules move so slowly that they kind of bond with each other. Liquids are moving slow enough that they hold each other together at a set volume, but can move around each other pretty freely, so they take the shape of what ever container they are in. Gases are moving so fast that they don't hang out together at all, they take both the size and they shape of their container. Sometimes these phase of matter mix together (see Part 1). Jell-O is a liquid dissolved in a solid, aka a gel. Simple enough right?

So, what makes Jell-O work differently than your shave gel? Gelatin is made of collagen, a protein in animals that connects bones and muscle fibers in the body (it is what makes meat tough). We buy this collagen in powder form. When the the gelatin powder is heated with a solution, like sugar water, it mixes in with the liquid to make a sol. When it cools it creates a crystal structure (see Cornstarch Crystal Conundrum) that has holes big enough to to be filled with really yummy liquid, and it becomes a gel. When it heats back up, the crystal structure falls apart again and the liquid seeps out. And that in a nut shell is Jell-O.

My take on Jell-O today is a little less American and a little more Italian. Panna Cotta is a tradition Italian dessert that uses milk and gelatin to created a creamy, dreamy, jiggly, plate of deliciousness. It is really easy to make and perfect if you are having a dinner party, because you can make it days ahead and just pull it out when dessert rolls around. I know it was a hit with my friends this weekend, and a lot less labor intensive than my little cannoli experiment. I got this recipe from the blog Sticky, Gooey, Creamy, Chewy (http://stickygooeycreamychewy.com/2010/03/16/dominator-honey-vanilla-bean-panna-cotta-and-why-i-love-facebook/) and made a few changes to the topping recipe. This is my version.

Perfect Panna Cotta (this made 10 small servings, easy)

Ingredients, Panna Cotta

1 cup whole milk

1 Tablespoon gelatin

3 cups heavy cream

1/4 cup honey

1/4 cup sugar

1 vanilla bean

pinch of salt

Place the milk in a small saucepan and sprinkle gelatin over it. Let stand 5 minutes. Split the vanilla bean and scrape out the seeds with the point of a sharp knife. Put the saucepan over medium heat and stir until the gelatin is just dissolved (do not boil). Add cream, honey, sugar, vanilla bean and seeds, and salt. Stir until the sugar and honey dissolve (5-7 minutes). Turn off the heat and let steep 15-20 minutes. Remove the vanilla bean pod. Pour the mixture into lightly greased molds, small jars, or glasses. Chill for at least two hours before topping.

Ingredients, Topping

8 oz strawberries

2 Tablespoons sugar

1 Tablespoon lemon juice

2 Tablespoons cold water

1/2 package gelatin

Blend the strawberries and sugar together until smooth. Heat mixture in a saucepan until it begins to bubble. Stir in the lemon juice and remove from the heat.* Place water in a small bowl and sprinkle the gelatin on top. Let sit for 5 minutes. Add fruit mixture and stir to dissolve. Let cool slightly. Pour over panna cotta and chill until set.

*The other alternative is just to stop here and pour the liquid sauce over the panna cotta just before serving, like I did in the picture.

Marvelous Mixtures Part 1, Sweet Southern Sol

In chemistry matter comes in two very broad categories, pure substances and mixtures. Pure substances are things like pure water, there is only one type of substance (atom or compound) present in any sample. Mixtures are everything else and are often described by whether or not the individual parts can be seen. If a mixture looks the same throughout it is called homogenous (like salt water). If it doesn't it is called heterogeneous (like a salad). I will talk about various kinds of mixtures that cover the whole spectrum at various points. Today we'll deal with a very specific type of homogenous mixture called a sol.

Homogenous mixtures are categorized by how large the pieces of the minor substance is. If the minor compound is an atom or molecule it is called a solution. If it is a little bigger, but small enough that the minor compound cannot be seen by the naked eye it is called a colloid. If it can be seen, it is known as a suspension. The different components can be solid, liquid, or gas and they don't have to be the same as each other. This is how we end up with all of the weird products that seem to be in between phases (like Jell-O). A sol is a very specific type of colloid where a solid is "dissolved" or "suspended" in a liquid. This is all in theory of course. In reality whenever a liquid has particles in it that don't separate out upon standing chemists will call it a solution. If the particles do separate out, it is referred to as a suspension.

Today the weather decided that we should have summer, real DC summer, a little early. We hit 90 degrees Fahrenheit (32 degrees Celsius or 305 Kelvin for those who spend all their time in a lab). So I decided to cool off with some of my sweet tea. A delicious and satisfyingly sweet sol. While the sugar does create a solution, the tea particles are too large for the mixture as a whole to be considered a solution, so a sol it is. And it is a sol that satisfies the soul.

Sweet Tea

Ingredients

4 cups water (plus enough to bring the final product up to a gallon)

3 family sized ice tea bags (or 12 normal sized tea bags)

a pinch of baking soda

1-1/3 cups sugar

Bring 4 cups of water to a boil. Remove from heat. Add a pinch of baking soda and 3 family sized tea bags. Cover and let sit for 15 min. Remove tea bags (you can throw them out at this point). Add sugar and stir until completely dissolved. Pour concentrate into a gallon sized pitcher and fill the rest of the way with water. Chill, pour, and enjoy!