Category Archives: Ingredient Basics

02/15/13

Egg White

On the surface of it, an egg white isn’t a very interesting thing. It’s colorless with very little flavor and is made up of about 90% water. However there’s quite a lot of magic in that last 10%. How so? Because that’s where the proteins are. The white contains about half the total proteins of the egg, most of which are different from those of the yolk, and which do some pretty interesting biological jobs. Some of them bind up vitamins, others digest cell walls, still others bind to digestive enzymes rendering them useless. All combined they serve to make the white of an egg a very unfriendly place for invading microbes. They’re a big part of the reason an egg can be stored for so long.

When they aren’t busy protecting an embryo, egg white proteins are great for bakers. They’re rather unique in that they can be uncoiled with just a whisk and a little elbow grease. At that point they’re fabulous for creating foams. The reason they’re so good at this is because they have regions along their length that love water (are hydrophilic) and other regions that hate water (are hydrophobic). The end result being that they love the surface of bubbles, as all the sections of the protein can get their needs met. They can stick their water-loving parts in water, their water-hating parts in the air, and they’re happy.

The nice thing is that once all those proteins are arrayed at the surface of the bubble, they begin bonding to each other, if rather weakly. The network they create reinforces the wall of the bubble, preventing it from popping, even if other substances are subsequently introduced (fat, sugar, etc.). The end result is a foam, but not just any foam: one that will continue to maintain its volume after other delicious components have been added. So say hello to meringues, buttercreams and all sorts of other lovely things I couldn’t live without. So thank you, boring old egg white. My kitchen would be a much duller place without you.

Filed under:  Egg White, Pastry | 8 Comments
02/14/13

Egg Yolk

That’s a very pretty, upstanding yolk, no? It’s the mark of a fresh egg. If you’re ever in a position where you need to evaluate the relative age of an egg, a yolk is a good place to start. If it’s fairly roundish and bright yellow, and is sitting high atop a slightly milky-looking mound of almost gel-like egg white, your egg is extremely fresh. Make cake, cookies or muffins out of it. Or better still cook it up, because fresh eggs make mighty good eatin’.

Old eggs are very different in their appearance just out of the shell. The white becomes very clear and watery due to a progressive change in the pH of the egg, which begins as soon as the egg is laid. That change in pH causes the proteins in the white to drift away from each other, dispersing the large aggregations that formerly made the egg white jelly-thick and whitish. As that happens the membrane around the yolk starts to weaken. More water from the white enters the yolk, diluting its pigments and giving it a pale appearance. As that happens the yolk membrane stretches out, causing the yolk to lie almost flat. If you’ve ever tried to separate an old egg, you know just how weak that membrane is after many weeks of sitting. If the egg is sitting at room temperature, the pH change happens many times faster.

But let’s talk yolk, shall we? Yolks are the food source for the chicken embryo (the little white bud that sits next to it). As such they contain large amounts of nutrients. Indeed the yolk of an egg contains 75% of the egg’s calories, 50% of the protein and all of the fat. For all that, the vast majority of the yolk is composed of water. A myth about egg yolks is that they’re very fatty. That’s not the case, as eggs are quite lean. A yolk contains just five grams of fat, only a fraction of which is saturated (the so-called “bad fat”).

True, egg yolks have gotten a bad rap in the past as a result of the relatively high amount of low density lipoproteins (LDL’s) they contain, and those structures have cholesterol within them. Lately the reputation of egg yolks has been rehabilitated, however, as more studies are showing that high cholesterol levels are more a factor of the way our bodies work than the food we eat.

But then if it isn’t the fat in egg yolks that makes them such great tenderizers of baked goods, what is it? Ah, glad you asked. The answer is: emulsifiers. Yolks, you see, abound with tiny structures, and structures within structures, and structures within structures with…well you get the idea. These tiny globules, which are all suspended in a watery medium, contain all the things an embryo needs to develop: proteins, fat, cholesterol and vitamins. The walls of these structures — which are designed specifically to keep water and fat separated from one another — are made up in large part of a compound called lecithin.

Take that lecithin out of the egg yolk and put it into say, a cake batter, and it performs a very similar job of keeping fats and water droplets separated from each other and/or combining into large masses. This has the effect of dispersing fat very evenly through the batter. And when fat is very evenly dispersed the result is a tender cake, as fat disrupts the gluten networks that make cake tough or chewy. An irony to this story is that very tender, highly emulsified cakes are also stronger than cakes that aren’t as well emulsified, since the crumb had a very fine, self-reinforcing structure (think of a lattice of beams holding up a domed roof instead of a big, central pillar). They have give, but tend not to fall apart and crumble, if that makes sense.

Yolks of course also impart a lovely color to baked goods because of the pigments they contain. The brightness of these pigments are largely a result of what the chicken eats. Alfalfa feed creates nice bright yolks, as does corn. If neither of those is on-hand many farmers add marigold petals to a chicken’s diet, which accomplishes pretty much the same thing.

Filed under:  Egg Yolk, Pastry | 6 Comments
02/13/13

Egg (Whole)

A post on eggs could go on almost indefinitely. However since I want to focus on the egg as ingredient, I’ll do my best to keep this short and useful. The logical place to start is: how are eggs used in the pastry kitchen? I can think of three main categories of use: as a structural component in cakes, as a thickener in custards and creams and as a foam in batters, meringues, frostings and the like. It’s a pretty crude taxonomy when you consider how much eggs offer the pastry cook in terms of flavor, enrichment and color, but it seems functional to me.

Eggs come in different colors, sizes and grades. For our purposes I’ll focus on the basic white, large (as opposed to “peewee”, “small”, “medium”, “extra large” or “jumbo” as defined by the US Department of Agriculture) chicken egg, since that’s what most pastry recipes printed in the States call for. They’re also the most commonly available egg for home bakers and commercial bakers alike. Those that use shell eggs, anyway. Large eggs weigh about two ounces. The white weighs about an ounce, the yolk about half an ounce and the shell accounts for the rest.

In the States eggs found in stores are graded either AA (top quality) or A. There are grade B eggs which are perfectly usable, but they’re generally not sold in the shell, rather they’re used for packaged carton yolk and white products. Below grade B are so-called “dirty” eggs which aren’t fit for human consumption and go to various sorts of animal feeds. Eggs are graded by “candling” i.e., shining a bright light on the egg an inspecting the shell and contents for defects (this is done by machine these days).

What do egg grades measure? Aside from shell cracks, blood spots and the like, which consign eggs to lower grades, the grade is a measure of the viscosity of the white and air cell size, which are both indicators of age. Older eggs have thinner whites and bigger air cells. Of course most of us reflexively gravitate to the freshest possible ingredients when we cook. Indeed we’re increasingly trained to do so. However in the pastry kitchen excellent arguments can be made for eggs that are, well, old. At least to some degree.

Why? Because old eggs have thinner whites, and that thinness makes them easier to whip. Imagine a whisk trying to cut through a bowl full of water versus one full of corn syrup and you’ll have a sense for what I mean. You can apply a lot more shearing force to the bowl full of water since the thickness of the medium slows your stroke down a whole lot less. All of which means that older eggs whip up faster and also higher. So if your focus is foam for meringues, macarons, soufflés and the like, grade A eggs will be just fine for your purposes. Even old grade A eggs. Also if you like to make hard boiled eggs old eggs are better since they’re easier to peel once they’re cooked (the membranes have pulled away from the inside of the shell).

What are some applications for very fresh eggs? Some bakers will say none. Most of those are Europeans, who tend not to refrigerate their eggs, so theirs are always “old” by American standards. However very fresh eggs are quite useful for some things we Americans like to bake: layer cakes and muffins for instance, where the thicker, more viscous whites create more viscous batters which tend to create more volume. Fresher eggs can also be nicer when you need to separate an egg, since old yolks have very thin membranes which frequently break when you try to separate them.

There is so much more to be said about eggs and how they perform, indeed a whole lot more than one post can contain. What I will say on that point is that we mostly value eggs for their proteins, and further the ability of those proteins to bind other elements together, be those elements sugar and flour (in the case of cakes), fat and water (in the case of custard) or cells of air (in the case of foams). Those proteins are like strings, and they occur in little balls or clumps inside egg yolks and whites in their natural state. We use heat — and in the case of foams, agitation — to coax those egg proteins to uncoil, at which point they’re available for all sorts of creative uses.

I’ll get into more of that when I talk about whites and yolks individually.

Filed under:  Egg, Pastry | 30 Comments
02/08/13

On Egg Wash

Several readers have asked that I go a bit in-depth on egg washes. I’m happy to oblige, though I have to confess up front that I’m not a big believer in the alchemy of egg washes. Unless you’re very much into the minute details of presentation — and I’m clearly not — a simple wash made of well-beaten whole egg will do you for most any job. Multi-ingredient washes made from egg, cream, water with a pinch of salt and a dash of sugar…homey don’t play dat.

Making sure the egg really is well-beaten and not merely scrambled in the bowl is the real key to a good wash, i.e. one that gives you a smooth and even finish. Blobs of egg white on the brush will not only give you an uneven glaze, the pockets of albumen will actually prevent the wash from adhering to the pastry’s surface. I use a fork (sometimes a mini whisk) to mix up an egg wash. I whip briskly until I can’t force myself to do it any longer (about 2-3 minutes, which is a long time when you’re just standing there over a tiny bowl…whipping).

It’s the yolk of the egg that provides both the color and the binding power. The binding properties of yolk have been known to artists for millennia. “Egg tempera” was the medium all serious painters used from ancient Egypt to up until about the Renaissance when oil-based paints displaced it. Egg yolk goes on smooth, dries hard and glossy and sticks remarkably well to a variety of surfaces.

So if yolk is so great for color, shine and crust why not just use it by itself? The answer: because unadulterated yolk dries way too fast. That’s not a good thing since it gets goopy on the brush. Also you don’t want the surface of your pastry to turn taught or brittle before the pastry hits the oven, where it will expand, causing that inflexible surface to tear. The glaze needs some give, which is where the watery white comes in. Combined, egg white and yolk create a perfect all-purpose glaze. It’s golden, it’s shiny, it’s crispy…what’s not too love?

But what if you don’t love it? What if it’s not shiny enough? Too shiny? Not brown enough? Not flexible enough? Well then there are things you can add to bring it more into line with your personal aesthetic.

Water. Water dilutes the yolk still more than the white does by itself. What you have then is a slightly less glossy and/or golden glaze with more flexibility. It’s a nice thing for glazing a pastry or especially a bread that’s really going to increase its surface area in the oven. A brioche, say, or a parker house roll. A teaspoon of water per egg is good for most pastry applications, though bread glazes can take up to two tablespoons of water per egg.

Milk. Milk added to a whole egg glaze accomplishes much the same thing as water, except that the milk proteins, sugars and fats create more of a semi-gloss or even matte surface. As with the water-whole egg glaze, adjust the amount of liquid according to the surface increase you expect. A teaspoon is fine for the top of a piece of puff pastry, which will simply be pushed upward. The surface of a parker house roll will blow up like a balloon. More flex is necessary.

Cream. Cream is generally used in place of the egg white to create a deep, dark, extra shiny and mostly opaque glaze. The fat in the cream keeps the yolk from drying out during application, and the proteins and sugars brown up in the heat, giving a richer appearance. I find a cream glaze too thick for all but the most static, un-expansive applications, like short crusts (pie borders, lattices and such, or tart crusts). One yolk to one teaspoon of cream is fine. You can use up to three.

Salt. It’s said that adding a pinch of salt will amp up the gloss of a whole egg glaze. Me, I’ve never noticed much difference. I strongly suspect this is a kitchen myth. What a pinch of salt will do, however, is dissolve the albumin and globulin proteins in the white, creating a thinner wash.

And that’s pretty much what I know about egg washes. What if you don’t like — or can’t eat — eggs but still want a glazed appearance on your baked good? Milk, cream or half and half are sometimes used as a glaze on breads or quick breads to give them a golden color. Here again more water means more flexibility and expansion without cracks in the finish. Use whole milk for a roll, heavy cream for a southern biscuit. Sugar sprinkled on a pastry (especially large crystal sugar) is very attractive in place of a glaze. Oil will also add sheen to the surface of a bread.

Filed under:  Pastry, Wash | 42 Comments
02/07/13

Egg Wash as Super Glue

Reader Flip writes to say that his kringle had some large cracks down the middle. He also mentions that cracks are a recurring problem with his laminated pastries, especially croissants, and wonders what he might be doing wrong.

Flip, my guess is it’s an egg wash problem. Though you might not think it, egg wash is a very strong glue, at least once it’s heated. If you paint your wash too low on the pastry, trying to increase the amount of glossy real estate, there’s a good chance you’ll get some egg wash on the pan or parchment. That can be disastrous from a presentation perspective.

For the egg wash will glue the edge of the outer layer of your pastry to the pan (or paper). It’s this layer that will have all the shine on it, but it’s also the layer that will get brittle the fastest as the pastry heats up (egg proteins start to harden at a mere 140 degrees Fahrenheit). What happens to this very thin, inflexible and immobile shell as the pastry underneath expands? It cracks open.

However if you’re careful to only apply wash to the top of the pastry, you leave expansion areas along the outer edges that can flex as the pastry starts to bulge upward and outward. The glossy top stays all in one piece. Thanks for an excellent question, Flip!

Filed under:  Pastry, Wash | 5 Comments
01/22/13

Clarified Butter

Clarified butter is what you get when you heat butter to the point that the milk proteins curdle and settle out, the minerals and sugars clump and rise to the top, and much of the water boils away. What you’re left with is nearly pure butterfat.

What’s the advantage of that? Well, once all that’s done butter starts to behave a lot more like oil, and that’s a handy thing when you want the flavor of butter but also want to be able to subject it to high heat. If for instance you want to sauté with it or even fry in it. For the clarifying process has the effect of raising the smoke point of butter from around 325 degrees Fahrenheit to around 425 degrees Fahrenheit, which is pretty darn amazing.

Odds are you’ve clarified butter yourself at one point or another, even if you weren’t intending to do it. Maybe you melted several sticks to make a filo pastry of some sort. As you worked you noticed the foam on the top of the butter and the film on the bottom of the pan. Later when you returned to wash up, you noticed that the butter had remained a semi-liquid once it had cooled. Even when refrigerated it never returned to its former firm state.

What you had there was ghee. If you remember from some of the earlier posts, butter is an emulsion: tiny droplets of water inside a matrix of butterfat crystals, free liquid butterfat and some protein-encased butterfat blobs that managed to survive the butter making process intact. Heat wrecks that emulsion, and more that that it curdles those protein coats, breaking the butterfat globules and freeing the butterfat inside. The result is a mass of nothing but free fat which can never go back to the emulsion from whence it came.

Is clarified butter useful in baking? It certainly can be, especially in cake batters (génoise, madeleines) where you want the moist texture that oil provides without completely sacrificing the flavor you get from butter. I say “completely” because much of the flavor of butter comes from the sugars and minerals you lose in the clarifying process. And if it this moment you happen to be asking yourself: does this mean I shouldn’t clarify expensive butter? The answer is an unequivocal “yes.”

Filed under:  Butter, Clarified, Pastry | 27 Comments
01/21/13

Oil

Oils are liquid fats. They are derived from plant sources (seeds, nuts, that sort of thing) and like animal fats have been in use by human beings for thousands of years. Speaking generally, they’re used more by cooks than bakers — solid fats are where it’s at for pastry types — but come in quite handy from time to time.

In the pastry kitchen oils are most valuable when they bring little-to-no flavor to the party. Though a walnut or a sesame oil might occasionally be used specifically for its flavor, most of the time pastry makers use oil solely to introduce richness and/or a moist texture into a cake or muffin formula. The same goes for frying, where the aroma of, say, peanuts or corn can muddle the profile of a fritter or a doughnut.

So the oils most commonly found in the pastry kitchen are neutral-tasting: vegetable (made from soybeans) and Canola (made from pressed rapeseed or mustard seeds). If they’re neutral in flavor and have a high smoke point, so much the better. As it happens vegetable oil has a smoke point of around 370 degrees Fahrenheit and Canola can take heat up to about 435. Gotta love those Canadians.

Other useful oils include corn oil (if you make a lot of corn bread) or olive oil which, even though it has a very distinctive flavor, is very nice for little Italian cakes. Olive oil is also rich in emulsifiers, and that can be extremely handy when you want to produce a cake with a very fine crumb.

Of course the word of pastry is wide, and the potential applications for oils of all types are legion. But I’m a simple man with simple needs. Give me a nice big jug of Canola oil and, for the most part, I’m good.

Filed under:  Oil, Pastry | 16 Comments
01/18/13

Shortening

Shortening is pure vegetable oil, hydrogenated to give it a firm texture. It’s different from margarine (another hydrogenated fat) in that it was not created to be a substitute for butter, but rather as a substitute for animal fat, specifically lard. How does it stack up? Rather well. Like lard it’s all fat with no water in it. That means it’s great for things like biscuits and pie doughs, which lose some of their crispiness and flake with butter because of the water butter contains.

Unlike lard, however, it’s completely neutral in flavor. It’s also quite a bit less expensive. It also melts at a much higher temperature, around 118 degrees Fahrenheit, which is a good thing for things like cookies and (American) biscuits, since you get a lot less spread. And did I mention it keeps indefinitely at room temperature? No wonder that the emergence of shortening in the very early 1900′s coincided with a steep drop-off in the popularity of lard.

Like margarine, the chief argument against it lately has been that it contains trans fats. In response to that criticism the food industry has developed a version without trans fats. This has been no easy feat, for as you may recall from the post on margarine, the process of hydrogenation only has two gears: full hydrogenation (which yields a fat that’s as rigid as ice) and partial hydrogenation (which creates at least some trans fats). The industry’s solution: to blend fully hydrogenated oil with liquid vegetable oil. It’s not a terribly easy thing to do, and produces a not terribly convincing fat, at least from a baking perspective. My own fiddlings with trans-free shortenings have been only mildly satisfactory. The biscuits don’t rise as high, aren’t as crispy and seem to me to have a different taste. Since I’m not worried about trans fats at all, I’ll skip it and go with the regular stuff, me.

In breads and other baked goods, shortening, like all fats, undermines gluten networks and hence the rise of the breads in question. Breads with a high proportion of fat are therefore shorter than their fat-free counterparts. Hence the word “shortening.”

Filed under:  Pastry, Shortening | 21 Comments
01/18/13

Schmaltz

Schmaltz is fat from a chicken. You don’t see it around much anymore, but once it was a very common thing in Germany and Austria, and among the peoples who emigrated from there, notably the Ashkenazi Jews. Though the word “schmaltz” can technically refer to beef, pork and even goose fat, it’s come to mean “chicken fat” among people who use it in the States. The cost common use for schmaltz was as a spread, which is to say it was used like butter on toast. However it makes a very nice general-purpose cooking fat as well, and is useful in baking as a tenderizer for doughs (I’ve used it in knish dough) and some crusts.

That’s where the utility of schmaltz mostly ends in the pastry kitchen because schmaltz isn’t terribly firm. Which means — yes you guessed right — that it’s lower in saturated fat than either pork or beef fat. And that makes it healthier in some peoples’ eyes. Schmaltz can be easily made at home by gently heating chopped pieces of chicken skin in a pan with a very small amount of water (some people add a few chopped raw onions to the pan to add flavor). After about an hour very, very low heat cooking, the fat melts and can be strained through cheese cloth or even paper towels into a refined fat. Once cooled you can use it for just about anything. In fact there was a soul food restaurant here in Louisville that used schmaltz instead of mayonnaise to make chicken salad. When that place closed I was depressed for a month.

Filed under:  Pastry, Schmaltz | 37 Comments
01/18/13

Margarine

Margarine is a vegetable oil-based fat that was created as a less expensive alternative to butter. Indeed the composition of margarine is very similar to butter, about 80% fat and 15% water, so the two can be used interchangeably. The earliest margarines can be traced back to mid-nineteenth century France. They were composed of beef fat mixed with water and milk solids for a butter-like flavor. When hydrogenation was invented around 1900, food scientists dispensed with the beef fat and moved to the purely vegetable-based formula we know today.

What is hydrogenation and what does it do? Well based on what you now know about fat, you can probably guess. It involves turning a liquid oil into a more broadly useful firm fat by adding hydrogen atoms to its fatty acid chains — which is to say, saturating them. This has the effect of creating more crystal-forming triglyceride molecules, and the fat firms (for all that, margarine still has a lower proportion of saturated fat than butter, lard or suet).

The problem with hydrogenating oil is that if you take the process all the way it creates a fat that’s so hard that it’s almost useless to a home cook. So margarine makers “partially” hydrogenate the oil in order to leave some free liquid fats in the mix. The problem with partial hydrogenation is that it creates a small proportion of trans fats which have become, shall we say, unfashionable in recent years. The funny thing is that all dairy fat contains a small proportion of trans fat and always has. It’s why organic butter can’t be labeled “contains zero trans fats”, because 5% of the fatty acids it contains have the dreaded “trans” bonds in their hydrocarbon chains. But when they’re in margarine or shortening they’re lethal. Go figure.

Oops, am I editorializing? Sorry. The point is that margarine, like butter, has trans fats in it. Margarine in stick form has more, but that’s because it’s firmer. Tub margarine is, by design, made to be spreadable even when it’s cool. However that soft consistency makes it unsuitable for most baking applications, especially laminated doughs. Firm stick margarine, by contrast, is perfect for an application like croissant dough. Indeed this very day there are more margarine-based croissants being made in France than natural butter croissants. And they are darn good!

Margarine melts at almost the same temperature as butter, often just a little higher — around 95 degrees Fahrenheit. That meams cookies made with margarine spread less in the oven as the starches in the flour have more time to relate and firm, and the egg proteins have longer to set.

Filed under:  Margarine, Pastry | 25 Comments