Chocolate Chip Cookies!

I am almost jumping out of my skin, I'm so excited. After several miserable failures of attempts to make beloved comfort food recipes (pumpkin bread, cinnamon buns and brownies), I finally have one of them back. Confession, I had to resort to the deal with the devil that is Splenda, but it was worth it. I'll earn my culinary soul back later, I have cookies! They look like cookies and taste like cookies and even have the right texture (allowing for the fact that I forgot to half the baking powder when I halved the rest of the recipe. Oops).

When you double the baking powder, this happens. I smashed down the next batch, but it hid the chocolate.

I don't feel I can really take credit for the recipe, since all I did was replace the sugar in THE recipe (you know what I'm talking about) with an equal amount of Splenda + 1 1/2 tablespoons of molasses per cup of 'sugar', doubled the eggs and entirely substituted almond flour for normal flour. I used bittersweet chips instead of semisweet, which brings in each cookie at around 4 net carbs, which works alright for me right now. If ever needed, I know of a decent sugar-free chocolate bar that can replace the chips and bring it down to a little over 1 net carb per chipwich sized cookie.

Is it sad that I miss cookies so much? Maybe. But I don't care, because I have chocolate. In cookie form. 

~PhysicsGal

Interferometers

Finally,  a physics post! is what exactly none of you are thinking.

When studying with a friend, it was brought to my attention that I cannot for the life of me remember the different types of interferometers and what you do with them. I can name them, I just can't remember what differentiates them. This is kind of a critical topic for my qualifying exam, so I thought I would write a post on it to try and help me to remember it. 

Interferometers are 'old tech' in the world of optics. The main types of optical interferometer were invented back in the 19th century, or very early 20th century. At this point in time, the number of subtypes of interferometers is vast. But except for a few exotic types, the principles of their operation fall into two camps: wave front splitting or amplitude splitting. The wave splitting interferometer splits a beam arbitrarily, either by use of two pinholes/slits, very thin prisms, or cleverly aligned mirrors, which essentially takes chunks of same beam. Amplitude splitting interferometers make use of a beam splitter, which divides the light into reflected and transmitted light, which divides the amplitude evenly.  Each has its uses, because they operate on different optical principles.

Wave-Splitting Interferometers

The wave splitting interferometer is possibly the simplest to explain, and if you've ever heard of or seen a Young's Double Slit Experiment, you know of the oldest, and easiest to replicate, of the wave splitting interferometers. Its success or failure depends on the spatial coherence of light. In other words, how similar is this part of the beam to any other part of  the beam? The way physicists usually quantify this property is in the coherence area. If a source is oddly shaped, and relatively close, it will be spatially incoherent, particularly if it is giving off 'broad band' or white light. You have a large group of random oscillators each creating its own wave, and the waves have nothing to do with each other. You will have a miniscule coherence area. However, oddly enough, if you can get far enough away from the source, the coherence area will increase! Why? Let's go to the ducks!

If you look at the water, and not the adorable ducks, you'll notice that near the ducks, the water waves are chaotic. Each duck is acting as an independent oscillator, going his own rate in his own location. But as the waves get farther and farther from the ducks, they look more and more like perfect spherical waves you would get from tossing in a pebble (a point oscillator). The incoherent bits cancel each other out at a great distance, and only the coherent bits survive, creating a spatially coherent wave. The same thing happens with light. The other way to think about it is the farther you get from something, the more it looks like a point sources. Starlight is highly coherent (that's why they seem to twinkle), but they are just as incoherent as our sun at the source. The only difference is distance. They are so far away, all that reaches us is the coherent waves. You can observe the same effect with a car headlight, if you live somewhere with low light pollution and enough space to walk a couple hundred yards or so away from the car. 

So lets say you've got yourself a spatially coherent source. These days, say a laser pointer will do if you can get your hands on sufficient small double slits. Otherwise, you can do as Young did, which was cut a small hole in the shutter he used to make his room totally dark, cover it with thick paper he had poked a pin hole in, and use the tiny amount of sunlight that filtered in as his source. 

By passing the light through two pinholes or slit, you are creating two identical beams of light, each producing uniform waves of light. If you then place a screen far enough away, you can view the interference pattern of the light, the spacing of which will depend on the separation of your slits and the wavelength of the light. How visible the pattern is is determined by the spatial coherence of the light. 

Dr. Young's original drawing of his experiment

The main use of this type of interferometer is to determine the coherence of a source. You could use it to determine the wavelength of a coherent source, but there are much easier ways to do that that don't require coherence. 

Amplitude Splitting Interferometers

The most basic kind of amplitude splitting interferometer is the Michelson Interferometer. Its many offspring are now more widely used than the original because they are more stable, easier to set up and generally less finicky, but the original is easier to explain I think.

This interferometer depends on a different type of coherence, namely temporal coherence, or how well the beam maintains similarity over time. This makes this type of interferometer very very sensitive to the coherence length of the beam (if a beam is not temporally coherent, a point in the beam that was produced a couple nanoseconds ago, and now a meter away, might not look at all like the beam that is just now being produced.)

The basic set up for this can be seen above.  Your light source is aimed at a beam splitter or a half-silvered mirror which divides your beam into transmitted and reflected portions equally. The split beams travel some distance, then reflect off perfectly aligned mirrors, travel back through the beam splitter and interfere on a screen or a detector. If the difference in the distance the beams traveled is smaller than the coherence length, an interference pattern will form. If the coherence length is short, or not of interest, a compensating plate can be used to eliminate the difference in travel time.

So, what can you do with this thing? You can use it to experimentally find the coherence length of a source by moving one mirror relative to the other until the interference pattern disappears.  You can use it to do metrology (measurements) and test the quality of your optical instruments.  You can use a variation of this in wind tunnels to study air flow patterns, or studying fluid mechanics. A really big version of this can be used in astronomy. Its probably easier to list the scientific fields that don't use some sort of amplitude splitting interferometer than the ones that do. A fiber optics based version of this, the Sagnac interferometer, is used in gyroscopes, but really deserves its own post. 

Interferometers were historically important for a whole host of reasons, including disproving aether, proving the wave nature of light and wave-particle duality of electrons. Today they have a million different uses in research and industry and continue to yield new insights into the universe. Its a shame they don't teach them in every basic science class.

~PhysicsGal

Fruit Pie, Take 1 and 2

There is nothing quite like apple pie once apple season starts. Apples are available all year round of course, but there is something about the start of school and the arrival of fall decorations that demands apple pie.

Pie requires a crust. In the old days, I would use good old all-purpose flour. These days, that's not an option, which means experimentation with oat and/or almond flour. I had previously (and very very recently) perfected the whole wheat crust, and having learned from my recent semi-failure with oat/almond crusts, I thought I had learned from my mistakes in the non-wheat pie crust department. Use less butter, more water, let it rest a good long while, work it a little more than you would normal pastry dough. Roll it out on wax paper.

This incarnation was definitely more pie-crust like than the last one. It rolled out alright, though it was still far more fragile than I wanted it to be. During baking it browned nicely, and got fairly flakey in places. Too flakey actually. Sadly, it still had the structural integrity of a crumb crust. The top crust collapsed as the apples underneath it cooked down, and extracting a slice is impossible. It resembles more an apple crisp than a pie when you dish it out.

The flavor for the crust was also somewhat lacking (the filling was perfect however-a little tart and a little sweet). I don't usually think of crusts having a flavor, but my husband complained it tasted a bit like cardboard and it was definitely lacking something. Butteriness for sure, what with the significantly lower butter content, something else was missing that I can't quite put my finger on. I suspect the 'cardboard' flavor comes from the oats, so I think the next incarnation will need some extra flavorings to mute that aspect. A little vanilla and cinnamon maybe.

The structure is a little tricker, but my theory was that I would have better luck making it less like a basic pie crust and more like a laminated pastry. The proteins in oats are not nearly as long and stretch or easily formed as the gluten in wheat. They need more coaxing to come out, as well as more time in liquid. An overnight rest for a very wet, low butter dough, then rolling out, buttering, and booking the dough like you would for puff pastry. I thought that the longer absorbing time, combined with the repeated rolling and folding will give me the protein structure I needed, while folding in the butter will give me the flakiness and buttery taste.

 So for my second try, I made up a very wet, low fat oat and almond meal dough, and pulsed it in the food processor a lot longer than I would normal pastry. It looked kind of like chocolate chip cookie dough made with really warm butter. Then I stuck it in the fridge until it firmed up.

Then I had to wait for it to soften before I could  do anything with it. Isn't that always the way? Eventually, I was able to roll it out into a rectangle, spread softened butter over the middle square, and book it, just like I've seen my mom do a hundred times with puff pastry dough for angel wings.

I did this three times, using two tablespoons of softened butter for each booking, which brought me up to a total of 1/2 cup of butter for about 3 cups of oat/almond flour. With each booking, the texture got smoother, and less crumbly.

First booking.

After 2 bookings.

At the end of it, when I cut it in half for top crust/bottom crust, you could kind of see the layers in the cross section.

My greatest hope for flakey pastry dough.

And then, back into the fridge to let the butter harden up.

The next day, I rolled out the dough. It was a little stiff, but it behaved almost like a normal dough. You could pick it up and move it without it falling apart, which was a huge step forward. I made it a little thick, but that's my preference.

You can see in the next picture, it actually holds up pretty well. You can see the edges are holding up their own weight against gravity and not crumbling.

My one error with this pie happened here. I used completely frozen fruit, and I didn't use enough of it. Live and learn. I was impatient.

The top crust also went on without incident, and stayed intact. I added an egg wash to aid browning, though that turned out to be unnecessary.

In cooking, the crust did sink down over the fruit.

But, this crust didn't crumble. It eats like a normal crust. Its a little flakey, and tender. It still has an oatiness my husband dislikes, but I think that's the nature of the beast, and is will be less noticeable if there is enough filling and the filling's spices are included in the crust. Overall, I think I have hit upon a good, if somewhat labor intensive technique for getting a good oat pie crust.

~PhysicsGal

Oat/Almond Pie Crust (makes 2 thick crusts)
2 1/2 cups oat flour
1/2 cup almond flour
Water
1/2 cup butter
honey/sweetner to taste
Spices to taste.

In a food processor, pulse together the flours and 2 tablespoons of butter, along with any honey and spices. With the  processor running, drizzle in enough water to make a wet, sticky dough like a cookie dough. Wrap, and refrigerate over night or longer.

Take dough out and allow to soften (how long will depend on the ambient temperature in your kitchen). Roll out into a rectangle on wax or parchment paper. Spread 2 tablespoons of softened butter over the central square. Fold in each side, and then fold the whole thing in half. Wrap, and let rest at room temp for 30 minutes. Repeat two  more times, then divide, and refrigerate for at least several hours. Roll out and use as you would normal pastry dough. If good browning is desired, use an egg wash. 

Midweek Thoughts

I have two food related posts and one physics post (yes, an actual physics post for my physics blog, shockingly) waiting in the wings, but I am too tired and preoccupied to do them justice until the weekend when I have more time to think them out properly.

Still, it felt odd not to write. When I was a kid, I wrote almost every day. Not diary type stuff, stories. But still, it felt right to write. Now that I am kind of back in the habit, when I don't write something I miss it. If it weren't for the wealth of science bloggers out there, I would feel very alone. With one exception, no one I know in my department finds writing to be easy, let alone enjoyable. Almost every core class made us write some sort of paper because "science majors don't usually have much experience with writing", and the spoken assumption is we don't read for fun and we certainly don't write.

Apparently there is a lot of thing science majors don't do, particularly female ones, though each department has so few the sample size is too small to really get statistics out of it. I have a life, for one, and am happily married. I am a person of faith. I cook and am decently versed in most needle crafts, to the point I make most of my clothes. And then there are the things I don't do. As an optics person, I must love cameras. I don't. I find them useful tools, and wish I could upgrade my rather dismal one, but I just cannot get excited about F/#s. As a hard science chick, I must love computer games. Again, not so much. And above all, I should not know anything about grammar, literature, or philosophy. Any paper I write should only be semi-intelligible and be almost entirely underlined in green when viewed as a Word doc.

Oh well. Let them have their games and their ramen. I'll enjoy a nice stew and write something. Writing on this blog seems to have rekindled whatever creative spark I had that college tried to kill, because stories have started floating back through my mind. Not fully formed, the way they used to, more half stories. The idea of an idea that might one day present itself as a story to be told. Until then, I'll keep writing about theology and cooking and the occasional physics post. If nothing else, it serves as a way to wind down when I feel like I am being pulled in multiple directions at once between my teaching, research, studying for my qualifier and the dozen daily chores of life.

Pumpkin Bread Failure

My mom's pumpkin bread has achieved as near to legendary status as is possible for non immortal baked goods. It was a staple growing up for breakfasts, snacks, lunch boxes, everything. It arrived on a regular basis in my college care packages, sustaining me through many papers, problem sets and exams.

Sadly, my mom's pumpkin bread is something I can no longer eat. So I wanted to reverse engineer one I could. It shouldn't be too hard right? I got muffins down on basically my first try, surely I could make pumpkin bread.

It started off well enough. Using my mom's recipe as a guide, I tried to make substitutions and adjustments based off of what I knew from making muffins. More liquid and leavening. Long rest to allow the flour to soak up the liquid. Extra eggs for stability.  It smelled right. It was the right color, and after resting in the fridge for a couple of hours it was the right consistency. It even looked ok while it was baking. I pulled it out when a skewer came out clean.

But it was a failure. It fell apart when I took it out of the pan. As it cooled, it wasn't cakey. It was mushy. Almost slimey. it was as though I had created some horrible hybrid of cake and pudding and unlike plum pudding or bread pudding, it was disgusting (it didn't help that I scaled back the sweetening a little too aggressively).

The sweetness thing is easy enough to correct. But I'm not sure what to do with this slime. The cake was done. It was as set as could be, but it was slimey. I think I may have to start from scratch, and keep only my mom's spice ratios.

Sometimes, experimental baking is very disappointing.

Return of the Liturgical Year

The title of this post is slightly misleading. Technically, the church's liturgical calendar never went on hiatus. But the summer months are filled with those interminable sundays labeled "N-th Sunday After Pentecost". These Sundays admittedly drag into the fall a bit, but its less noticable because regular church operations resume. Sunday School starts back up, Bible studies resume, the pastorate plunges into a new sermon series, choirs start practicing. We put away the lackadaisical-ness of summer, with those light airy anthems, and, if the church lack air conditioning, begin contemplating wearing cassocks and cottas again.

Some nice anglican priest who posts pictures to WikiCommons

Don't get me wrong. I love a good summer anthem, and the summer sermon series can be well done. But have you ever heard a truly riveting 18th Sunday after Pentecost anthem? Is there such a thing? Has anyone gotten really excited to go to church because it's the N-th Sunday after Pentecost?

I love getting back into the fall because I have so much to look forward to. Two of my favorite anthems (excluding Christmas and Easter) always came into the rotation in October and early November. "At the Round Earth's Imagined Corners", by the late great Lee Hoiby with a text from John Donne's sonnets was my favorite even before I really understood what it was talking about. The music is just so wonderfully perfect, ranging from bombastic and triumphant to somber and grim to quiet and contemplative, perfectly fitting the text to music, and its hard to beat Donne for religious poetry outside of the psalms. The other answer is based on Psalm 107 by : "They that Go Down to the Sea in Ships" by Hurbert Sumions*. The first reason is purely silly. Midway through the anthem, there is the line "They reel to and fro/And stagger like a drunken man", to music that brilliantly illustrates this idea, and growing up I swear our choir swayed slightly while singing it.  The second is it is simply a beautifully written anthem that captures the motion of ocean waves, the terror of sailors caught in a storm, and the relief at being brought home safely. Growing up, I waited all year long for these anthems. When I was big enough to turn pages but not old enough to sing I liked to turn pages for "At the Round Earth's Imagined Corners". It was fun sitting on the organ bench for the loud bits with all the pedal work. Almost as fun as Widor's "Toccata" at Easter. 

We also start getting Sundays where the church wears colors other than her "workaday green", as Dorothy L. Sayers so nicely put it. Christ the King, with white drapings and triumphant hymns. Advent with its purple and candles and hymns of hope and expectation. The wonders of Christmas white, plus candles and greenery. Even without special clothes, we get the special Sundays of World Communion and Reformation Sunday. And it continues like this all winter long, and into spring, until we hit Pentecost and the interminable Sundays that come after it. 

Although a lot of people, my husband included, don't see the point of the liturgical calendar, I enjoy it. I like that it gives a rhythm to my year. I also like the fact that it walks us through every aspect of the story of Salvation. The liturgical year begins with Advent, our hopeful anticipation of the arrival of Emmanuel, God with us. Christmas marks his arrival in the world. Christ's baptism by John. Lent, when we are supposed to contemplate all the ways we have failed God, renew our devotion to him, and think on how lost we would be without Christ's redemptive act. Holy week, going from the emotional high of Palm Sunday to the despair on Good Friday, to the joy of Easter morning  when we proclaim "He is risen! Alleluia!" The happiness of post Easter, Ascension and Pentecost, when red banners fly to symbolize the tongues of fire. And then, work a day green. After all the excitement of Christ's years on earth, we are left with work to do. Get down to evangelizing, caring for the poor, doing the work we are called to do until Christ comes again. The church year ends on Christ the King Sunday, when we celebrate Christ's triumphant return in Glory, a reminder of what we are working for. And then the cycle starts over again, spiritual renewal through the winter so we can go about our work again the next year.

This spring and summer have been emotionally, spiritually and physically draining for me. I'm glad to get back into the renewal part of the church year, because I feel the need of it.

I think this post is a little less coherent than I meant it to be, but hopefully you can forgive me that.

* Corrected from Henry Purcell. Who also wrote a version, but not the one I'm talking about. 

Pancakes!

Pancakes used to be a Saturday morning tradition on our household. Freshly made from scratch, I had perfected my art. If I was feeling really fancy, I'd serve it with the maple syrup warmed  up in a little pitcher like my mom used to do (when we were really little, she gave it to us in this little itty pitcher that held maybe a tablespoon; it let us feel decadent and grown up, without wasting anything. Brilliant woman).

Recent events kind of put the kibosh on this tradition. I'd make them just for my husband sometimes, but it wasn't the same. I wanted to salvage it, with a pancake I could eat and one my husband would eat.

I should say a little something about my husband I feel. He is very much a meat-and-potatoes man. A red-blooded American man circa 1940. He likes meat. He likes white bread and pasta. He does not like vegetables. He does not like whole grains. He could probably live on pizza, hamburgers, pretzels and the occasional pie. That being said, he has been a real trooper through this whole experience. He has gamely tried to help me eat some of my more horrific experiments (the unsweetened carrot spice cake, the rye lemon cookies), has cheered me when something comes out tasting 'normal' and has meekly submitted to an increase in beans and vegetables on his dinner table. He doesn't complain hardly at all about the 'hippie' food, but when he actually says "That was good", I know I've hit on something.

These pancakes are one of those 'somethings'. They have the right texture, and the oatiness is way in the background. They are slightly more delicate to flip than normal pancakes, but otherwise act like pancakes should, and taste darn close.

Start with about 3/4 cup of fine oat flour, 1/4 cup almond flour, and 1 tablespoon baking powder. Mix well or sift together.

 Beat together 2 eggs, 2 teaspoons of vanilla (or half that amount of  your flavoring of choice), a tablespoon of honey or maple syrup and enough milk to bring it to a full cup (just how much will depend on the size of your eggs).

Pour this into your dry ingredients, and beat. Unlike wheat flour, which contains gluten, oats contain no gluten (unless contaminated at the mill), and the proteins it does contain take a lot more coaxing to hold things together. Once it is smooth (at least a minute or two of beating), it should have the consistency of a crepe or swedish pancake batter.

 Now, let this sit. In 10 minutes its a good consistency for my kind of pancake, wait more like 20 minutes for cake-ier pancakes. Go make your coffee. Drink your first cup of coffee. If you are using a cast iron pan, put it on the burner to get hot. Then the batter should be perfect.

Melt some butter or oil in your pan of choice (mine is a small non-stick). And yes, that is butter. Yes, it really is that yellow, thanks to beta-carotene in the milk of grass-fed cows. Now I know what color Mrs. Blandings wanted her dining room.

Pour in your desired amount of batter. A quarter cup gave me  a four inch diameter pancake, which was about perfect.

Cook until it starts to bubble in the middle. This batter cooks a lot faster than normal pancakes, which makes up for early wait time, but it means you can't walk away while its cooking.

Flip, carefully since its slightly more fragile, and cook until the second side is brown, about 30 seconds.

Interestingly, these pancakes tended to get a deeper brown, without burning. This was the point that I eventually settled on as my favorite.

The flavor is not very different from normal pancakes. A very, very faint oatiness if you know its there, and an aftertaste of vanilla (I like my pancakes vanilla-y, but that's a personal preference). My husband declared them 'good', which is roughly equivalent to a 4 star review for him, and as I said before, he does not like 'healthy' tasting food. 

The quantities listed above yielded 7-8 pancakes, which was enough for 2 breakfasters plus one left over for a mid morning snack. You can always double the quantities as needed. Serve however you like your pancakes. Enjoy!

~PhysicsGal

Oatmeal Pancakes

(Serves 2-3)

3/4 cup fine oat flour

1/4 cup fine almond flour

1 Tbsp baking powder

2 eggs

2 tsp vanilla

1 Tbsp honey or maple syrup

Milk to bring total wet ingredients to 1 cup

Mix dry ingredients to thoroughly combine. Beat together wet ingredients, then pour into dry. Beat until smooth and slightly thickened, 1-2 minutes. Let sit 10-20 minutes, depending on desired consistency. Cook with a little butter or oil in a cast iron or non-stick frying pan on medium high heat, turning when bubbles form in the  middle. Serve with butter, maple syrup, sliced fruit, or just plain plain.