Daring Bakers

Marcelle and I have joined a great group called the Daring Bakers. Each month they send out a recipe that everyone is to follow and then on a given day everyone posts their results on the same day. August was our first month with the group and we made éclairs. We made a hazelnut cream filling with a chocolate toping. To quote our toddler son they were "DEElishush."

This, however, is a blog about science, so I want to talk about the science behind éclairs. The dough is very simple to make. First water, butter, and milk are brought to a boil, then flour is stirred in all at once. The dough that forms is stirred and cooked for a few minutes on the stove to swell the starch. Then you transfer the dough to a mixer bowl and eggs are beaten in, one at a time. The dough is piped onto cookie sheets and baked in a hot oven.

You notice that there is no chemical leavening agent included in the dough, such as yeast or baking soda, and yet it forms lots of wonderful air pockets during baking. How does this happen? Steam forms as the puffs bake and the strong gluten structure formed by beating the dough stretches to hold the steam. With the steam trapped, the heat then coagulates the gluten and egg proteins forming a rigid wall that will hold its shape. If done properly, the puffs will be golden brown, with a hollow center crisscrossed by a soft network of dough filaments.

Each ingredient plays a part in making a good puff. First the water, milk, and butter need to be boiling so that when the flour is added it will swell (hydrate) the starch granules and gluten (gluten is made up of two proteins gliadin and glutenin). The more butter you add, the more tender the cream puff will be, but if you have too much it will interfere with the gluten stretching and the cream puff will collapse.

The eggs that are beaten into the dough act as the leavening agent. The yolks add fat and act as an emulsifier for a smooth and even texture in the finished product. Egg proteins add to the structure of the cream puff as it cooks.

Baking any dough is a delicate dance between two processes: the expanding of gas and the coagulation of gluten and gelatinization of starch. If the oven temperature is too low, the trapped air will expand and escape before the gluten and starch have set. The puff will collapse and be a tough mass. Also, the puffs depend on steam production to cause the to rise: if the temperature is too low there won't be enough steam to cause the puff to rise, and if the temperature is too high, the proteins and starch will set and brown before the gas has expanded to its full size. This will again lead to unpuffed puffs.

This recipe was an exciting start to our membership in the Daring Bakers Club. I felt like many of the components were unnecessarily complicated--for example, the best glaze for eclairs I've ever tasted (and had great success with) is a simple 5/4 chocolate/cream ganache. It doesn't get any easier than making it in the microwave. The glaze recipe we were instructed to follow to the letter never set up, not even after time spent in the cool of our freezer for a while. It included silly component recipes (which tasted great as ice cream toppings) but did nothing to further our desire to repeat this recipe experience. The choux recipe chosen for us by this month's host was a good one, although many important instructions were omitted from the instructions--like how wide the puffs should have been in addition to how long, and whether they should cool on racks or on sheets or on parchment paper pulled off the sheets and placed on a counter/table. Dave complained that it seemed like this recipe was intended to dirty as many dishes as possible, and because he is our "dishwasher," he should know. We thought the double chocolate hit from the pastry cream and the glaze would be too much (even for confirmed chocolate lovers), so we opted for a hazelnut pastry cream that we created from our vast store of experience making hazelnut gelato and it turned out really nice. We WILL be making that part again. All in all, this was supposed to get us cooking together in the kitchen, which happened three nights in a row this week for us to get all our components together. So, in that way, despite my quibbling, it was an unqualified success! ---Dave's lab assistant


Chinese Chemistry

I really enjoy looking at the Periodic Table. I love the amount of information that is available in such a condensed form. I like the Table so much that I carry one in my wallet. There is one in the kitchen (in English) and one in the bathroom (in Spanish). As I was thinking about the periodic table I began to wonder what it looks like in Chinese. It just so happens that I work with a couple of Chinese guys so I asked them to show me a Chinese periodic table. I noticed right off that all of the Nobel gases had one shape in common throughout the family. Then I noticed that it wasn't just the Nobel gases but all of the gases had the same character. Then I noticed that the metals had another character and last the non-metal solids another character. My labmate explained that in Chinese the majority if the symbols are made up from two parts. The first part (the radical) tells you what the physical state of the element is at STP. The second part is phonetic and tells you how to pronounce the symbol.

I learned (after installing the East Asian languages on my computer) that there are four radicals used on the periodic table and they were the shapes I had noticed at the beginning. They are 金or 钅(literally "gold" for metal), 石 (literally "stone" for non-metal and metaloid solids), 水 or 氵 (literally "water" for liquids), and 气 (literally "air" for gases). The phonetic part is based on the western name of the element. Below you can see some examples of this radical phonetic symbol pairing.

Here "metal" and the phonetic "bi" combine to form bismuth.

"Metal" plus "nei" form "na" for natrium or sodium in English. I like this one because it shows that they aren't just using the English pronunciations of the elements.

"Stone" and "dian" form iodine.

"Air" combines with "fu" to make fluorine.

There is set class of symbols which are for elements that were known since ancient times. Elements which were known to the Chinese alchemists like gold, iron, sulfur, and mercury. I especially enjoy the symbols for iron and sulfur. Iron can be broken up into several parts.

Which could be interpreted "metal from the mountain for making weapons." Sulfur can be broken apart to show that it is a stone that flows.

Lastly there are some characters that are descriptive of the element that they represent. Examples are phosphorus and bromine. Phosphorous breaks down to "the stone that glows" and bromine is the "stinky liquid."

Some of the websites that I found especially useful are Zhongwen, a website about Chinese characters and their etymology, the Wikipedia entry on the chemical elements in East Asian languages, and an IUPAC article on the Chinese terms for chemical elements.