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!

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.

Sriracha Ice Cream

For the past year or so, I have had the idea of savory or savory-inspired ice cream churning in the back of my mind. Pun Intended. Although I don't think I'll go as far as "clam raisin," mentioned in David Lebovitz's The Perfect Scoop, I do have a list of flavors building up:

• Curry, perhaps mixed with rice like a rice pudding ice cream
• Guacamole
• Avocado-Bacon
• Corn/Corn-Bacon
• Pepper
• Goat Cheese (perhaps with honey)
• Pho sorbet
• Lemongrass
• Tomato-Basil soup
• Butternut squash
• Sriracha

As you can probably tell from the title of this post, I started with the bottom of the list. This sriracha ice cream is more "savory-inspired" than actually savory; it contains sugar and vanilla.

The ice cream is sweet, hot, and salty. The first bite is very weird, but I found that I liked it more as I continued to eat it. The spiciness doesn't build up until the third or fourth spoonful, and it never gets unbearable because of the sugar and cream. This flavor is definitely worth trying if your are a Sriracha fan.

When I brought this to the dorm lounge, I got mixed reactions. My roommates actually liked it, but one of my friends literally spat out the ice cream, drank some soda, spat that out too, and then had a cookie to make sure all traces of the ice cream were gone. It was quite a show. I recommend offering this ice cream to people under the name "Mango Ice cream" and taking pictures of their faces as they dig in enthusiastically.

You may be wondering, how does one make this strange ice cream? Since I don't have a kitchen this year, I opted for a "philadelphia-style" cream. That means that instead of making a custard by cooking egg yolks in milk, I just added some flavor to cream and froze it. I went off of the recipe I found here.

Sriracha Ice Cream

• 2 cups heavy cream
• 1 cup milk (fat percentage is not very important)
• 3/4 cup sugar
• 2tbsp to 1/4 cup sriracha (rooster sauce), to taste
• 1 tsp vanilla

1. Make sure the frozen part of your ice cream maker is frozen.
2. In a medium bowl, combine the sugar, sriracha, and vanilla. 



It looks like blood-spattered snow...

3. Stir well.






4. Add the cream and milk, stir until the sugar is dissolved






5. Add more hot sauce or sugar to taste.
6. Put in the ice cream machine and churn for 20 minutes.
7. Transfer soft serve ice cream to a container and freeze for at least 3 hours.

The freshly churned cream is much lighter in color than the frozen ice cream (top)

The churned ice cream will have a strange sticky texture, but it will feel fine when eaten. Enjoy! (Or psych out your friends.)

A study on Ginger and Saffron

My family recently went to the "molecular" restaurant Beaumé, and one dish there that particularly interested me was the turbot with turmeric cream, chanterelles, and pickled kohlrabi. Beaumé cooked the turbot "sous-vide" and placed it in the bright yellow sauce. The pickled kohlrabi added a nice bright touch to the soft dish.

Beaumé's turbot

Inspired by this dish and by the saffron my family received as a gift, I decided to make a variation on this recipe. I was curious about the combination of ginger and saffron, so I put together a menu using both spices.

The Menu:

• Cod poached in ginger, kefir lime leaves, and lemongrass
• Colorful vegetables in dashi and ginger broth
• Saffron rice pilaf
• Saffron and Ginger bechamel

The cod and vegetables turned out well. For the vegetables, I found a bundle of heirloom carrots (purple, red, and yellow) to which I added leeks and celery. I boiled some water with dashi granules, ginger, lemon grass, and kefir limes leaves to make a flavored broth for both the vegetables and fish, and I added more ginger to the vegetables as they cooked. 

The carrots

The vegetables

The rice did not go as smoothly. I bloomed the saffron in boiling water to try to get the flavor and color out of it, but the rice did not end up becoming yellow. My mother says that I should have have ground up the saffron with a mortar before blooming it. Well, now I know! And even though the rice was not yellow, it still tasted of saffron.
To make the pilaf, I sautéed some leeks in a tbsp of butter, then added the riced and sautéed it for a couple minutes as well. I made a broth of saffron juice (saffron + boiling water + kefir lime leaf + time) and a cube of vegetable bouillon. Per traditional pilaf method, I added enough broth to cover the rice, brought it to a simmer, and then stirred/added more broth as needed until the rice cooked through.

The Bechamel was tricky. I heated some milk with saffron and ginger to get flavor. In a saucepan I cooked 1 tbsp flour in 1 tbsp melted butter for a couple minutes and then added the milk a little bit at a time, stirring well after each addition, until the sauce was the desired thickness. Because I don't have much experience, my sauce ended up a bit curdled, so I strained it to remove the bits. Like for the rice, the sauce was not yellow because I had not ground the saffron before infusing the milk.

To replace the kohlrabi, I made some pickled ginger (this recipe, it was a bit too salty)

And here is the final plate.

Bento #1: Hoisin salmon, spinach, carrot kinpira, and sushi rice

Sooo I started my job this week, but my job does not have a physical location, so I work whereever I want to. Today I decided to work at the library, so I made myself a bento lunch. I had been wanting to try making bento for a while (I was especially inspired by justbento.com; I even bought her cookbook!)
In today's bento I put some leftover hoisin glazed salmon and vietnamese spinach that I had frozen last week. I also had about 3/4 cup of "sushi rice" (read more to learn why I put quotations there) and some carrot kinpira, blanched bean sprouts, and "pickled" cucumber from the Just Bento cookbook. I had prepared the carrots and bean sprouts last friday, and they were fine today, although not as delicious as they were fresh on Friday. Especially the carrots, those were really darn good. The salmon was a tad dry, but the spinach was good.

The rice, however, kinda failed. It was mushy and the flavor ratio was off. I think one issue is that I put too much water in the rice cooker because I was trying to cook only half a cup of rice but the rice cooker does not have half cup markings. I also was not sure how much vinegar mixture to put into the rice. Well, with practice I'll get the hang of it.

As a sidenote: this recipe looks delicious.

Spring Break 2: Bread-y stuff

So on Thursday I pulled out my beloved The Bread Baker's Apprentice by Peter Reinhart and made some bread. I made a caprese-inspired loaf by putting fresh mozzarella, sundried tomatoes, and basil in Challah dough (I'm sure this is terribly sacrilegious) and pizza.

For the Caprese Bread I made the challah dough per the instructions of Peter Reinhart. To incorporate the filling into the dough, I stretched out the dough like pizza, placed the filling on top, and rolled it up like a log. 

And then I split it into 3 and braided it!

I also made pizza dough (also from Reinhart's book) that I rested in the refrigerator overnight. As toppings for the pizza, I roasted some brussels sprouts and broccolini in a 400 degree oven for 20 minutes, then I turned the oven down to 330 for another 10-20 minutes. For sauce, I blended some canned diced tomatoes and cooked them with onions, garlic, and oregano.

I made 3 pizzas, one with brussels sprouts, broccolini and caramelized onions (not pictured), one with broccolini, copa, and caramelized onions (first), and, at my dad's suggestion, one with chorizo, brussels sprouts, roasted garlic, and an egg in the center (second). The chorizo one was the family favorite!

 

 And on Pi day (3/14) I visited my friend and we made pie!!! (We did not have enough crust dough to make a complete top crust, so we put a circle on top instead! It is off center on purpose.)

Chocolate cake: A scientific method

I am in France right now! But before I blog about that, I will tell you about my attempts to make a near perfect chocolate cake.

A few weeks ago, a friend asked me to bake a cake for another friend's surprise birthday/goodbye party. A commission of sorts! How honoring and surprising! I was told that the recipient like chocolate cake, and the theme of the party was Pink Lemonade (pink and yellow), so I was a bit stumped on how to combine them. I personally am not a fan of lemon and chocolate (I am actually not a fan of any lemon desserts), so I figured I could just add pink and yellow food coloring in a couple places. Unfortunately, chocolate cake is not very easy to color... I considered red velvet, but the one time I tried to make red velvet cupcakes, they did not turn out well at all. And by at all, I mean at all. As I only had 1.5 weeks to prepare, I wanted to stay on the safe side.

But how to add color to a chocolate cake? White chocolate frosting.

I began with the base of the cake. I wanted the base to be good, not just sweet and fluffy, so I gathered a couple recipes. I decided to try two of them: a relatively simple recipe from Scharffen-Berger (that I had made before here) and a more complicated recipe from Cook's Illustrated (which was surprisingly available on their website while I was making the cake, but is now only available to subscribers here). I made half of each recipe to get one layer of each.

For the frosting I turned to one of my favorite cookbooks: I Want Chocolate! by Trish Deseine. I made half of her recipe for Easy Chocolate Ganache, substituting white chocolate for dark. If I remember correctly, it used about 3/4 cup for 8oz of chocolate. This turned out to be a bit to liquid for my purposes, so I had to almost freeze my ganache for it to be thick enough. I often find frosting to be too rich, so I wanted to test two different ganaches, a heavier one (just cream and chocolate) and a lighter one (cream, chocolate and whipped cream). So I made both and colored the heavier one yellow and the lighter one pink.

Then I assembled my test cake. On the bottom I put my layer of simple cake,

 then I spread some heavier frosting,

 put the complicated cake,

and spread the lighter frosting. I did not have enough lighter frosting to cover the entire cake, so it ended up looking pretty ugly. That's why I had a test cake!

Then I had my parents test the cake. I did not tell them which layer corresponded to which cake (because that would have biased the data. I should have made two half cakes, one with the layers in the opposite order, for less bias, but I was worried that would not be stable).

Results: First, the top layer is lighter colored. However, it was also found to be more strongly chocolatey, as well as more tender and lighter than the bottom layer. The bottom layer was not found to have any redeeming qualities in comparison with the top layer. Fortunately for me, the choice was easy. Unfortunately, the chosen cake was the more complicated recipe.

As for the frosting, I decided that I liked having the two types, but that I should switch their positions.

Making the final cake:

I had originally planed to have a second practice cake, but I was out of time, so I went directly to the final cake. I made the full Cook's Illustrated recipe for the base and made ganache with 12oz of white chocolate and 3/4 cup of cream. I put the lighter frosting in between the cake layers and tried to spread the thicker frosting on top. However, the thicker ganache was now too thick to spread easily, and cake crumbs got mixed into the frosting, ruining the smooth finish:

To solve this, I made another batch of ganache using 8oz of white chocolate and spread it on top of the previous layer of frosting. For decoration, I had made letters and shapes with colored melted white chocolate:

The cake was a success, my friends really liked it!

A note: for all of this, I used white chocolate bars. I strongly recommend NOT using so called "White Chips" as these contain absolutely no cocoa butter and have a very different texture when melted.