Flour, Gluten and Strudel by Sarelle, in Chicago.

Last Monday (Sep 22) Walder Kitchen Science guru Sarelle Weiner did it again at the new Walder Science Center in Chicago.

Just as she did in Modiin, Israel, Sarelle presented another great session focusing on flour types, protein content, and the properties of gluten.

After familiarizing the 9 participants to flour combinations made from flours of different of varied season wheat, Sarelle emphasized that professionals weigh their ingredients to maintain a consistently excellent product. Measuring cup volumes often results in inconsistent product because the volume is often measured inconsistently. You can't go wrong when you weigh out ingredients.

After that, we learned about gluten's properties. Gluten is made from 2 proteins, glutenin and gliadin. Glutenin provides extensibility, making it possible for the dough to stretch out. Gliadin provides the elasticity making the dough bounce back when its rolled out and keep its shape. The dough's balance of glutenin and gliadin determine the products ultimate flakiness, chewiness, and crunchiness.

In the case of strudel dough, Sarelle taught the group how to coax, cajole or otherwise persuade the dough to such a level of thinness that you can read a newspaper through the dough. The news printed on the paper under the dough wasn't so great, but the strudel was extraordinary! And just in time for the Rosh Hashana table.

The session ended at the end of 2 hours with everybody enjoying the strudel of their labors. Both sweet and savory. Edges cut off from the stretch dough provided the culinary bonus Sarelle promised. They were deep boiled in honey and cinnamon as taiglach - honey knots especially to bring a sweet new year!

STAY TUNED as Walder Science Center is having Sarelle taking her experience to your neighborhood in Chicago and all over Israel.

Shanna Tova.

Another Walder Kitchen Science Slam Dunk on Sunday May 11th

So what can you learn from cooking vegetable soup?

Just ask the kids from the Walder Kitchen Science Vegetable Soup exploration today, Sunday May 11th!

Biology, Chemistry and Physics!

We started off by viewing the streaming videos from the International Space Station and learning about the Earth's atmosphere. When not directly involved with learning about vegetables and cooking our soup, we tracked the ISS using the global tracker over both hemispheres and witnessed both Sunday's sunset and Monday morning's sunrise.

Ah! But what does atmosphere have to do with cooking vegetable soup? Plenty! Atmospheric pressure relates to boiling point which was demonstrated by shaking a soda bottle and slowly opening the cover. The Earth's atmosphere as seen by the ISS boils water at 100C at sea level. But what about on the top of Mount Everest? And what about on the shore of the Dead Sea? The same veggie soup is cooked more quickly at the Dead Sea than at sea level and more quickly at sea level than at the top of Mount Everest.

Enter, the pressure cooker! We compared a pressure cooker to a standard pot, described its features needed to cooked the veggie soup under pressure. So instead of allowing all that wonderful heat laden steam when boiling is achieved, the cooker's lid locks the evaporate in; causing the boiling to rise, causing the water to absorb more heat from the stove and forcing that heat into the food because it cannot escape!

And that is not all! Oh no, that is not all!

We also learned that heat cooking (heat transfer) takes place on the surface of the food. So the more surface the food has, the faster the food cooks. And how, pray tell, does one increase the surface area of veggies for soup? Chop, chop, chop!

We had a great time peeling and chopping our carrots and potatoes and onions and celery and mushrooms to increase their surface area to speed up the cooking process which was further sped up by increasing the atmospheric pressure in the pot!

When Rabbi Weiner announced that it was time to increase the veggies surface area, our 5th and 6th grade participants knew exactly what to do! Cut and chop away!

We also learned that the incense spices in the Beit Hamikdash (Ancient Jewish Temple in Jerusalem) were chopped and crushed to burn well and smell really good! All the while the Kohanim (Priests) chopped, they chanted "We chop it well, very well we chop!" (היטב הדק, הדק היטב). 

But, of course, all this chopping took place after we examined our variety of vegetables and learned about leves, root systems, transpiration, respiration, and nutrient storage and photosynthesis.

And after stirring our biology together with the physics we added a dash of chemistry and talk about the chemicals released by onions when applying a mechanical force with a knife and cutting into its cells.

All is a day's soup.

We finished our session 2 hours later enjoying a healthy bowl of soup watching Monday morning's sunrise over the Sea of Japan from the International Space Station.

Everybody wants to know what's cooking next time in the Walder Kitchen of Science. 

Salt and Cream of Tartar affecting foaming of egg whites during whipping

From: Nathan A Unterman
To: Heshy Weiner Date: Wed, 12 Mar 2014 07:33:39 -0500
Subject: Salt, egg whites, Cream of Tartar

Salt increases the whipping time of the egg whites and decreases the stability of the foam. This is because salt dissolves into positive and negative ions. These ions bond with proteins, which disrupts the foam from forming. To protect the foam, salt is normally added after the whites have been beaten to the foamy stage.

Acids (vinegar, lemon juice, cream of tartar,etc) are also added after the foamy stage has been reached because they delay foam formation. Acids are useful because they stabilize the foam. Acids decrease the pH, which reduces the ability of the proteins to coagulate.

Cream of tartar: Potassium bitartrate, also known as potassium hydrogen tartrate, with formula KC₄H₅O₆, is a byproduct of winemaking.

-- 

Nathan A. Unterman

Recap of last Sunday's Walder Kitchen Science on Leavening March 2, 2014

itchen science for children on Sunday March 2nd was also excellent! 
We focused on Leavenings.
We started off asking the participants if they remembered what we did a week ago. 
Finally it was remembered (with a little of my prodding) that we learned about the makeup of the egg and the uses of yolks and whites.
We established that the structure of meringue cookies was constructed by whipping egg whites into a foam. This happens as we use mechanical force to attach air bubbles to the hydrophobic end of the egg white proteins.
We came to describe the process in which air bubbles are used in the formation of baked structures as "leavening".
Then, we discussed other methods of leavening, or generating air bubbles into a dough.

1. Using a living micro-organism called 'yeast' that eats and digests sugars in the flour and 'burps' out carbon dioxide bubbles. The yeast derives its energy from the food it eats and performs a chemical reaction releasing CO2 during digestion. Because it's a living organism, yeast does its best work at ambient or slightly warm temperatures. Put yeast in a hot oven and you kill it. Dead organisms don't eat or burp.

2. Using in inorganic chemical called sodium bi-carbonate, or baking soda. Soda is a base that will react with acids in the dough when water is introduced. The chemical reaction releases CO2 in the form of bubbles into the dough. Because baking soda is not alive, not only does one need to add heat to provide energy for the reaction, adding additional heat accelerates the reaction, sometimes too much. This leavening agent does its best work in a hot oven.

3. Some doughs do not have a great deal of acid in their mix to react well with baking soda. To remedy that, baking soda, the base, is mixed with weak acids like monocalcium phosphate or sodium aluminum sulfate to kick start the leavening reaction. The mixture is called 'baking powder'.

4. One can also leaven using steam, but we do not currently have the equipment that forces steam bubbles into a baking mix.

Using this information, we had a short discussion about the main difference between chametz and matza. Air bubbles, or leavening! The Torah tells us to avoid, on Pesach, baked goods pumped up with air bubbles, or leavened. On the other hand, we are supposed to eat a baked bread with as little possible air in it - matzah. We spent a few minutes on why that might be so.

The participants then designed an experiment using the following variables: Heat level (frigid, ambient, hot), and leavening used (none, yeast, soda, powder)
We formed 4 doughs. 1 with no leavening. 1 with yeast. 1 with baking soda. 1 with baking powder.
We split each dough into 3 pieces. 1 piece of each dough was placed in the refrigerator. Same for an oven warming at about 100F. Same for an oven at 350F.
Therefore, there were 4 pieces of dough representing each of the 4 leavening choices in either the fridge, the ambient oven and the hot oven.

While the participants observed the doughs through the windows of the toaster ovens, they worked on making 'matzahs' - pounding the dough flat, making holes with a fork and placing into a hot oven.

then we took some time to predict what we will expect to find. During this discussion, the participants volunteered that rising time and baking time were important variables, just like the leavening chosen and the temperature at which to leaven the dough.

After about a half hour we removed placed all the doughs in front of us on a table and compared and contrasted, size and shape. We then cut them open and described what we found. All the while attempting to explain the differences noted among the doughs.

Of course, we said Hamotzi on our matza and had that as a snack while we discussed our results!
We then reviewed and summarized what we learned, sang birkat hamazon together and adjourned.
They had a great time.

Egg Yolks and Egg Whites

In our next Kitchen Science program, we will be focusing on the properties and uses of eggs. Egg yolks are used as an emulsifier binding fats like oil with water in bread and cake baking. Egg whites are used to build structure around air bubbles in meringues. Two interesting links are Food Additives athttp://www.understandingfoodadditives.org/pages/ch2p2-2.htmand Science of Eggs athttp://www.exploratorium.edu/cooking/eggs/eggscience.html

Using a meat thermometer

The last thing that you would want is for a guest of yours to contract Salmonella or E Coli. To make sure that doesn’t happen, you must know that the center of the meat or fish has been adequately cooked. Once you know that the center of fish has achieved 140°F (60°C) and the center of meat 160°F (72°C), then you also know that not only has the center cooked, but that also all the meat surrounding the center is safe (harmful bacteria has been killed).

Using a meat thermometer that probes the interior of meat will let you know when your meat is safe to eat and not under or over cooked. Additionally, by keeping the thermometer inside the meat at a buffet table, you can monitor the meats internal temperature to keep it safe.

In the meanwhile, don’t lose sight of 2 important side points: 1) meat continues to cook internally after being removed from the fire. 2) The rate at which the meat’s surface heats up is faster that the center. Cooking at a lower, but safe temperature for a longer period of time will avoid drying and burning of the meat’s surface.

Using a deep fry / candy thermometer

When deep frying and making candy, the temperature of the liquids reaches a very high level. For example, caramelizing sugar heightens the temperature of the liquefied sugar to a level in excess of 300°F (149°C)! An oven thermometer which is manufactured to measure the heated air inside an oven is not adequate to measure the heat of the center of a liquid.

A special thermometer for candy making and deep frying is inserted into the liquid during the heating process. Usually the thermometer is very long for safety purposes so that you don’t burn yourself. Also, a hook attaching the thermometer to the side of the pot makes sure that it measures the temperature of the liquid and not of the pot.

Using Refrigerator and Freezer Thermometers

How efficiently is your refrigerator or freezer cooling? How efficient are you in ensuring that your vegetables at the back of your fridge are not becoming a wilted mess from freezing or your refrigerator milk spoiling prematurely from a warm environment? Have you set your freezer to the coldest setting? Maybe you’re burning energy needlessly because your stored food as frozen just as well at a lower setting?

Use thermometers in your refrigerator and freezers. The dials on the back of the appliance only raise or lower the temperature. They do not indicate what the internal temperature is. Besides, are you aware that in different seasons you need to adjust the dial to maintain the same internal temperature?

Using thermometers is the only way to make sure that you are using your appliance correctly and maintaining the proper internal temperature.