Berke Family Pretzel Making!

Last December after I was unexpectedly able to be home for Christmas my mother sent me back to Hawaii with the Berke family recipe for German pretzels, passed down through generations of adventurous Berkes over the course of two centuries and two continents, all the way back across the sea to the Berke family bakery in Germany (which is still there today), to before an enterprising scion of the family decided to try his luck in the New World (though it should be noted that Berke is not a German name and we don't know where our intrepid forebears migrated from, though I have my theories…).

With that melodramatic opener out of the way, it's not like it's a secret recipe or anything. This weekend I upgraded my computer from Debian 8 to Debian 9, and while it was busy upgrading and I was twiddling my thumbs I decided to try making the Berke pretzels for the first time on my own (I've helped my mom make them in the past), and since I took some pictures along the way I'm going to share the recipe and process here in case anyone else wants to try (or I ever lose the hard copy!). You're going to need a few things to start with…

You can also see the chili I was cooking simultaneously in the crockpot in the background.

First, microwave ½ cup of lard with 2 cups of water for a minute or so until the lard melts. While that's heating up, sift together 3 cups of flour (preferably bread flour), ⅔ cup of powdered milk, ⅓ cup sugar, ½ teaspoon salt, and 1 tablespoon of yeast (as seen above).

Add the water/lard mixture to it and mix. This is best done by hand, as the mixture is incredibly sticky at this point. Add ⅓ cup more water and continue mixing, adding up to 4 cups of flour 1 cup at a time. Keep mixing and kneading with your hands until the dough is just not sticky (this may require a little more flour; it did when I made them).

The right hand knows what the left is doing, and is very grateful it's too busy taking photos to be involved.

This dough is so sticky I can only hope my fingers are still attached; I haven't seen them in about 5 minutes.

At this point, pour a little oil in the bowl and slosh the dough around in it so the top is oiled, then set to rise for about an hour (cover the bowl while the dough is rising).

I ended up letting this dough rise about 2½ hours by accident.

Now, give that dough a good punch.

Punch!

Next, start some lye water. Mix 2 tablespoons of (food-grade) lye (sodium hydroxide, NaOH) in ~2 quarts of water over very low heat in a glass or enamel pot ONLY. Don't let it boil, and use plastic utensils! (The lye water will react with metal such as aluminum to create hydrogen, so don't let it spill and keep away from sources of open flame. You can flush it down the drain when done, though.)

To prevent boiling of the lye water you can use an improvised bain-marie like this one

 Next, roll out the pretzels. An easy way to get a good size is to divide the dough into 36 pieces.

Yes, I know. My pretzel-shaping skills are abysmal.

 (You can let them rise a little after this.) Next, prepare some pans by covering them in heavy-duty aluminum foil and spraying liberally with Pam. Then start dropping pretzels in the warm lye water one by one for ~15 seconds before placing them on the prepared pans.

I'm being very careful here not to let the metal handle touch the water, while taking a photo with the other hand.

That foil is quite necessary if you don't want the lye water messing up your pans.

Sprinkle with kosher sea salt to taste, then bake for 10 minutes at 400 °F. (In my experience, what seems like a lot of salt when you're shaking can be hardly noticeable after baking. See the salt in the pictures below? I could barely taste it, so don't be afraid to be liberal with it.) If they come out looking like the ones below, congratulations, and enjoy!

As you may be able to tell, my ability to make a pretzel shape is pretty much nil, and this pretzel expresses my feelings on the subject pretty accurately:

First Grumpy Cat, now Grumpy Pretzel.

Anyway, that's all there is to it! Well, “all.” It's a significant amount of work and will take at least a few hours, so you may want to make a double batch to get more pretzels out of it (three dozen will go surprisingly quickly!) A hui hou, and happy baking!

Science Clock Series: Part I

For Christmas my parents got me a novelty clock with scientific references for the numbers which I put up in my office. It's a nice clock, although this was the best picture I could get of it:

Now, since there are a lot of different scientific references on this clock I decided to write a mini-series on them, each post focusing on one of the numbers. Although I'm familiar with nearly all of them there are a few that I myself need to look up, so it'll be a learning experience for me as well. I'll be explaining as many of the scientific concepts that come up as I can for those who aren't familiar with them.

Today I'm going to start with number one:

\[\rho\ \text{of}\ \text{H}_2\text{O}\ (\text{g/cm}^3\ \text{at}\ 4^\circ\text{C})\] The Greek lower-case letter \(\rho\) (rho) is traditionally used to represent density in chemistry; H\(_2\)O is water, made up of two hydrogen atoms and one oxygen atom. The g/cm\(^3\) notation means grams per cubic centimeter, so the whole expression means “the density of water in grams per cubic centimeter at four degrees Celsius,” which refers to one.

Why it equals one is rather interesting. Fundamentally it equals one by definition; water is such an important and ubiquitous substance (it makes up 65-70% of the human body, covers 70% of the Earth's surface, etc.) that it was chosen such that the mass of one cubic centimeter of water was equal to one gram (or equivalently one gram of water occupies one cubic centimeter), so that the density of water is exactly one by definition. Thus, you can immediately tell if a substance is more or less dense than water at a glance by seeing whether its density is greater or less than one. If a substance's density is less than water it will float in water; if greater, it will sink. Sodium, for example, has a density of 0.968 g/cm\(^3\), or 96.8% that of water, meaning that sodium will just float on water. (Or at least, it would if it wasn't reacting so incredibly fast with water to produce hydrogen and igniting it in powerful explosions.) Magnesium, with an atomic number merely one higher than sodium, has a density of 1.738 g/cm\(^3\), 70.38% more dense than water, so magnesium would sink in water.

However, there's a wrinkle with this whole scenario that the critically-minded among you may have been wondering about: it turns out that the density of a substance varies with temperature. For most substances, the density decreases as the substance gets hotter, and increases as it gets colder. The reason for this is that greater temperature means greater average energy on the molecular level, which translates into higher average molecular speed, which tends to lead to increased molecular spacing and thus the same amount of mass taking a slightly larger area. Typically the changes in density are fairly small for liquids and solids, larger for gases.

As I mentioned, most substances increase in density as the temperature decreases, and this is mostly true for water; however, it has a slight hiccup as it approaches its freezing point. Rather than decreasing monotonically as the temperature decreases to 0\(^\circ\)C, the density of water reaches a minimum at 4\(^\circ\)C, then begins to increase slightly as it approaches its freezing point.

This behavior is unusual, thought not entirely unique; there are a few other substances that display similar quirks. However, in water's case, this little quirk is quite important for life on Earth. Because of this quirk, ice floats on liquid water, which is highly unusual (most solid substances sink in their liquid forms). Ice is a pretty good insulator, so ice forming on the surface of lakes helps keep the water beneath it from freezing more, leaving liquid regions underneath throughout the winter where fish and other creatures can survive. And when spring comes, the ice floats on the surface of the water where it can be melted by the Sun, rather than sitting out of reach on the bottom of lakes and rivers.

This quirk of density is but one of the many ways water is a very unique substance (one reason it was chosen to define density), but that isn't the focus of this post which is already getting a bit long. Next time we'll take a look at something from nuclear physics! Click here to jump directly to it.

Burning questions of a Saturday morning.

So there I was lying in bed this morning, still half-asleep, when I got to pondering the fact that I, like the atoms that compose me, am made up of 99.99% empty space. I then idly contemplated the fact that most of this mass was in the nuclei of my atoms, at which point I was seized by a burning desire to find out how much all the electrons in all the atoms of my body put together weighed.

I know that last I checked, I had a mass of approximately 60 kg (my weight is left as an exercise for the reader), and a little searching on the 'net produced a table with the percent-by-mass composition of an average person. Starting with the first entry in the list, I have around \(61.35\text{%}\cdot 60\ \text{kg} = 36.81\ \text{kg}\) of oxygen in me. That's 36,810 grams of oxygen. A mole of oxygen being 16.00 grams, that's almost exactly 2,300 moles of oxygen in me.

(A mole, in chemistry, is simply a very large number \(-\ 6.022\times10^{23}\), to be exact. The conversion between grams and moles is pretty easy; if you have an amount of a substance equal in grams to the atomic weight of one atom (or molecule) of that substance, you have one mole of that substance, i.e., \(6.022\times10^{23}\) atoms (or molecules) of the substance. Since the atomic weight of oxygen is 16.00 atomic mass units, one mole of oxygen is 16.00 grams of oxygen. One more of oxygen at \(0^\circ\)C and normal atmospheric pressure would occupy about 22.4 liters, or just under 6 gallons.)

Now, each oxygen atom comes with 8 electrons in tow, \(8\) electrons \(\times\) \(2,300\) moles \(\times\) \(6.022\times10^{23}=1.11\times10^{28}\) electrons.

That...is a very large number. (11.1 billion billion billion).

And that's just the first element on the list! (Although, by virtue of its nature, it is likely to provide the largest number of electrons.) Next up is carbon, which, at 22.83%, comprises 13.70 kg of me. Dividing by 12.00 grams per mole, and multiplying by 6 electrons to each carbon atom, we arrive at \(3.09\times10^{27}\) electrons from carbon, a factor of 10 less than from oxygen (not surprisingly).

Since the procedure is relatively boring, and quite simple, I will spare you further talk and simply list the amounts in the table below:

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oxygen        36.81 kg  \(1.11\times10^{28}\) electrons

carbon        13.70 kg  \(3.09\times10^{27}\) electrons

hydrogen      6.00 kg   \(3.57\times10^{27}\) electrons

nitrogen      1.54 kg   \(4.64\times10^{26}\) electrons

calcium       0.86 kg   \(2.58\times10^{26}\) electrons

phosphorus    670 g     \(1.94\times10^{26}\) electrons

potassium     120 g     \(3.51\times10^{25}\) electrons

sulfur        120 g     \(3.61\times10^{25}\) electrons

sodium        84 g      \(2.42\times10^{25}\) electrons

chlorine      84 g      \(2.43\times10^{25}\) electrons

magnesium     18 g      \(5.35\times10^{24}\) electrons

iron          6.0 g     \(1.68\times10^{24}\) electrons

fluorine      2.4 g     \(6.85\times10^{23}\) electrons

zinc          1.8 g     \(5.00\times10^{23}\) electrons

silicon       0.60 g    \(1.80\times10^{23}\) electrons

rubidium      0.60 g    \(1.56\times10^{23}\) electrons

strontium     0.30 g    \(7.84\times10^{22}\) electrons

bromine       0.24 g    \(6.33\times10^{22}\) electrons

lead          0.12 g    \(2.86\times10^{22}\) electrons

copper        0.06 g    \(1.65\times10^{22}\) electrons

aluminum      60 mg     \(1.74\times10^{22}\) electrons

cadmium       60 mg     \(1.54\times10^{22}\) electrons

cerium        60 mg     \(1.50\times10^{22}\) electrons

barium        18 mg     \(4.42\times10^{21}\) electrons

iodine        18 mg     \(4.53\times10^{21}\) electrons

tin           18 mg     \(4.57\times10^{21}\) electrons

titanium      18 mg     \(4.98\times10^{21}\) electrons

boron         18 mg     \(5.01\times10^{21}\) electrons

nickel        12 mg     \(3.45\times10^{21}\) electrons

selenium      12 mg     \(3.11\times10^{21}\) electrons

chromium      12 mg     \(3.34\times10^{21}\) electrons

manganese     12 mg     \(3.29\times10^{21}\) electrons

arsenic       6.0 mg    \(1.59\times10^{21}\) electrons

lithium       6.0 mg    \(1.56\times10^{21}\) electrons

cesium        5.4 mg    \(1.35\times10^{21}\) electrons

mercury       5.4 mg    \(1.30\times10^{21}\) electrons

germanium     4.2 mg    \(1.11\times10^{21}\) electrons

molybdenum    4.2 mg    \(1.10\times10^{21}\) electrons

cobalt        2.4 mg    \(6.62\times10^{20}\) electrons

antimony      1.8 mg    \(4.54\times10^{20}\) electrons

silver        1.8 mg    \(4.72\times10^{20}\) electrons

niobium       1.2 mg    \(3.19\times10^{20}\) electrons

zirconium     0.60 mg   \(1.58\times10^{20}\) electrons

lanthanum     0.60 mg   \(1.48\times10^{20}\) electrons

gallium       0.60 mg   \(1.61\times10^{20}\) electrons

tellurium     0.60 mg   \(1.47\times10^{20}\) electrons

yttrium       0.54 mg   \(1.42\times10^{20}\) electrons

bismuth       0.42 mg   \(1.00\times10^{20}\) electrons

thallium      0.42 mg   \(1.00\times10^{20}\) electrons

indium        0.36 mg   \(9.25\times10^{19}\) electrons

gold          0.18 mg   \(4.35\times10^{19}\) electrons

scandium      0.18 mg   \(5.06\times10^{19}\) electrons

tantalum      0.18 mg   \(4.37\times10^{19}\) electrons

vanadium      0.12 mg   \(3.26\times10^{19}\) electrons

thorium       0.060 mg  \(1.40\times10^{19}\) electrons

uranium       60 μg     \(1.40\times10^{19}\) electrons

samarium      42 μg     \(1.04\times10^{19}\) electrons

beryllium     30 μg     \(8.02\times10^{18}\) electrons

tungsten      18 μg     \(4.36\times10^{18}\) electrons

---

(if you're wondering about the units, conveniently, 0.06 g = 60 mg and 0.06 mg = 60 μg)

If you add all those electrons up, you come up with a total of \(1.88\times10^{28}\) electrons. That's a lot of electrons -- 18.8 billion billion billion, to be exact. But how much mass do they have? And how much do they weigh?

Finding the mass is easy. The mass of an electron is \(9.11\times10^{-31}\) kg so \(1.88\times10^{28}\) of them together have a mass of 17.1 grams, which has a weight of approximately 1/25 of a pound.

Wow. All the electrons in my body make up a measly 0.0000029% of my mass. Everything else is concentrated in the nuclei of my atoms. Wild, huh?