Orange Peels and Liquid CO2

This post is not about food. Well, it not about eating food. Although eating did happen. This post is about Science. With a capital S.

This post is about a molecule called limonene. As you may be able to guess from the name, limonene is what makes citrus fruit smell cirtusy. It looks like this:

limonene

For my carbon compounds lab, we extracted limonene from orange peels. If you know anything about organic chemistry, you can see that limonene is made only of carbons and hydrogens. So, it is rather non-polar*. The traditional way to extract limonene is to mix watered orange peel mush with diethyl ether. The diethyl ether is less polar than water, so the limonene goes hangout with its bat-shaped buddy. Then you let the layers separate, like oil and water, and keep just the diethyl ether layer. Yay! But now your limonene is floating around in anesthetic diethyl ether, so you pour your solution into this cool spinning vacuum pump that vaporizes the solvent to purify your limonene.

diethyl ether (see, it looks like a bat!)

* A "polar" molecule is one with an uneven distribution of electrons such that one side of the molecule is more negative than the other. This happens because the elements to right side of the periodic table (O, Cl, etc) tend to be more attractive to electrons than elements to the left, like C and H.

Getting limonene is all very great, but you used a fair amount of solvent that must now be disposed of as hazardous waste. This is expensive and not very green. What to do?

Enter carbon dioxide:

carbon dioxide

As you can see, carbon dioxide is a linear molecule, so even though the oxygens pull on the electrons, they cancel each other out and neither side of the molecule has a higher electron density than the other. Therefore, CO2 is non-polar. CO2 is also a gas, which makes it not very convenient for dissolving things. However, if you look at the phase diagram below, you can see that we can get liquid CO2 by raising the pressure. 

CO2 phase diagram (from wikipedia)

To recap: carbon dioxide + pressure = liquid carbon dioxide. liquid carbon dioxide + orange peel = extracted limonene.

Here is the set up for the extraction:

I zested an orange.

With a copper wire and some filter paper, I set up a little stage for the orange peel to be elevated above the bottom of the centrifuge tube.

I packed dry ice (solid CO2) above the orange peel, capped the tube and dropped it into hot water. 

Here pressure builds up in the tube and the carbon dioxide melts, dribbles through the orange peel, taking limonene with it. Since the cap's seal is not completely gas-tight, the carbon dioxide finds ways out and vaporizes, leaving limonene at the bottom of the tube. 

I repeated steps 3 and 4 four times to build up limonene at the bottom.

Now I have limonene without generating any hazardous waste! Yes, carbon dioxide is a greenhouse gas, but the dry ice was made from CO2 that was already in the atmosphere, so there is no net harm. 

Here is a video of the dry ice melting:

Of course, at the end of the lab period, we all ate our oranges!

Bagels

Hi! I made bagels. They were round, and had a hole in the middle. See?

Just like a bagel should be. And it wasn't even too difficult! I followed the recipe in Peter Reinhart's The Bread Baker's Apprentice. Sure, there were a couple specialty ingredients, such as malt powder

I got this stuff from my local beer brewing store.

and high gluten bread flour, such as King Arthur brand, but all in all, the recipe is pretty straightforward. 

These bagels have a pretty crusty crust, and a dense and chewy crumb. I recommend eating them.

The recipe takes 2 days. The first day is pretty involved, but you only need an hour or so on the second day. According to Reinhart, allowing the dough to ferment slowly overnight allows it to develop deeper flavors. to get maximum flavor, this recipe uses both a sponge and overnight fermentation. 

The quantities listed will make 12 standard sized bagels

Ingredients:

Sponge

• 1 tsp instant yeast (none of that old fashioned active dry stuff)
• 510g / 18oz / 4 cups high gluten bread flour (It is generally better to measure flour by weight or mass rather than volume, because flour density is very variable.)
• 2.5cups water

Dough

• 1/2 tsp instant yeast
• 482g / 17oz / 3.75 cups high gluten bread flour
• 2 3/4 tsp salt
• 2 tsp malt powder

To Finish

• 1 tbsp baking soda (although this quantity doesn't mean anything because Reinhart does not specify the amount of water to dilute it in...)
• toppings: sesame seeds, poppy seeds, rehydrated dried garlic/onion, cheese, salt, etc... 

  

  to rehydrate, just add water!

Method (slightly simplified from the original):

1. Mix together the "sponge" ingredients, the dough should look like pancake batter.
2. Let the sponge sit, covered, at room temperature for 2 hours (until it is foamy and bubbly and has doubled in size.)                                          



bubbles!

3. To the sponge add the "dough" ingredients. Stir well with a spoon or your hands to form a coarse, shaggy dough. 
4. If you are kneading by hand, turn out the dough onto a floured surface and knead for 10 minutes. If you have a stand mixer, have the machine knead the dough with the dough hook for 6 minutes.   Either way, the dough should be "satiny and pliable, but not sticky" (Reinhart).
5. Divide the dough into 12 pieces (each about 128g / 4.5oz). Cover with a damp towel and allow to rest 20 minutes.
6. To make the bagel shape, poke a hole into the center of a piece and shape the dough into an even bagel shape. The hole should be about 1 in in diameter. 
7. Line 2 sheet pans with parchment paper, and place the raw bagels on it. Let the dough sit for 20 minutes, then put it in the fridge overnight or for up to 3 days. 

   

   transporting bagel dough

8. The next day, preheat the oven to 500F and bring a wide pot of water to boil. Add the baking soda to the water.
9. Take the bagels out of the fridge and drop a couple of them into the water (only as many as can fit comfortably on the surface of the water)
10. Boil the bagels for one minute on each side. 

    

    boiled bagels

11. Sprinkle the baking sheets with semolina or cornmeal and place the boiled bagels on it. Top the bagels with desired toppings (I like sesame+poppy+garlic.) Note: to prevent the garlic from burning, you need to soak it in a bit of hot water to rehydrate it before using.

    

    toppings!

12. Bake the bagels for 5 minutes at 500F, rotate the pans and bake until golden, about another 5 minutes.
13. Let the bagels cool for 15 minutes on a cooling rack. 

    

    Om nom nom

14. Slice the bagel open, and spread with cream cheese! 

    

    No bagel is complete without cream cheese.

     



Cheese on top is also good.

Chocolate Cream Dacquoise

Hey ya'll, it's me again, and I have a Chocolate Cream Dacquoise to present to you: [hazelnut meringue, chocolate cream, whipped cream]x3 + [hazelnut meringue, whipped cream, caramelized hazelnuts].
 This dessert is a bit more complicated than my usual adventures, but it was christmas, which in my family means "time to eat lots of food", so I figured it would be a good time to try something fancy. Of course, as I was making it, I was convinced the meringues had burnt and that the pudding had curdled (it had, twice), but it turns out it is very difficult to make hazelnuts, cream, and chocolate taste bad.

Because this dessert is a pretty big undertaking, I'm too lazy to type up the recipe, so instead I'll entertain you with my research about dessert naming.

Dacquoise: a female inhabitant of the city of Dax, or a dessert made of layers of hazelnut or almond meringue filled with buttercream.

The red flag is Dax.

According to en.wikipedia.org, a marjolaine is a dacquoise with chocolate buttercream. However, fr.wikipedia.org makes no mention of marjolaine. In fact, searching for marjolaine in Google.fr only brings up marjoram, pictures of women named Marjolaine, and websites in English gushing about the supposedly French dessert of marjolaine. However, when I searched for "marjolaine dacquoise" in google.fr and insist on only pages in French, I do get a couple hits for French blogs making marjolaine.

Conclusions: Marjolaine is much more widely used to refer to a chocolate Dacquoise in English than in French. The small amount of usage in French is possibly due to feedback from English (French is currently borrowing a lot of words from English).


General gist of recipe (from Trish Deseine's I want Chocolate):

2 cups of hazelnuts

stirred into 12 beaten egg whites and 3/2 cups of sugar to make the meringue. This mixture is formed into 4 disks and baked for an hour at 275F.

For the chocolate cream, I beat 6 egg yolks, 1/4 cup sugar, and 2 tbsp flour until pale and frothy. I heated up 3/2 cup cream and 3/2 cup milk until almost boiling, and poured it into the egg yolks.

The yolk-cream was put back in the pan and brought to a boil (this is where the curdling happened, whoops!). Once the cream thickened, I added 4oz dark chocolate and stirred well. I cooled the cream in the refrigerator.

Now the layering! Meringue, chocolate cream,

whipped cream, grated dark chocolate. 

I made some caramel, mixed in some roasted hazelnuts, and crumbled it all on top.

The chocolate cream is kind of oozing everywhere. 

We're supposed to eat turkey or something

We celebrated this year's Thanksgiving with our wonderful friends the M family. Yesterday's dinner menu included:

• Roast Turkey (Traditions must be observed)
• Catherine M's Chestnut Stuffing 
• Green beens with lemon
• My dad's Pommes Anna
• My brother's Ginger Cranberry Sauce
• Cornbread
• Hazelnut and Fuyu Persimmon Salad
• Pumpkin Pie
• Sara M's Maple Pots de Crème

I read Bon Appetit Magazine, and in their Thanksgiving issue this year they found issue with using stuffing as stuffing because it prevents the bird from cooking or some other nonsense. They even decided to call their stuffing recipes "dressing" to discourage putting them inside turkeys. This name change doesn't even make any sense because, at least in my experience, dressing is a flavorful sauce. I do not believe that bread mixed with various vegetables/meats fall in that category.
In any case, if your stuffing is hot when you put it in the turkey, it isn't going to prevent the turkey from cooking, and the turkey juices will make the stuffing that much better.

Enough ranting. For the potatoes, my dad found a recipe in that same Bon Appetit magazine for "Mini Herbed Pommes Anna" , which are basically cakes of potato slices layered with butter and herbs. This recipe turned out delicious, and it can be easily made into advance, so I recommend it to anyone who needs a showstopper side.

My brother is the family cranberry expert, and he found a recipe for ginger-lemon cranberry sauce. The sauce came out strong and savory, not as sweet as more classic recipes. The ginger complemented the the rich gravy quite well. 

I made the Hazelnut/Persimmon salad and the pumpkin pie. For the salad, I first toasted some hazelnuts in the oven at 400F for 10-15 minutes (stirring them often). According to Catherine M's instructions, we peeled the hazelnuts by rubbing them in a dish towel.

We then sliced up some fuyu persimmons (the ones with rounded bottoms: they're not astringent) into a cider vinegar-olive oil-mustard-black pepper vinaigrette and added some mixed greens and arugula. The sweetness of the persimmon was nicely complemented by the tartness of the vinegar and the bitterness of the arugula.

For the pumpkin pie, I used Cook's Illustrated recipe, which can be found here http://www.seriouseats.com/recipes/2008/11/cooks-illustrated-pumpkin-pie-recipe.html . I really like this recipe because it combines canned pumpkin with fresh sweet potato to give a complex flavor. Compared to the pumpkin pie from the dining hall I had eaten last week, this pie tasted full and complete.