About Fats and Dairy Products
| Vegetable Oil | Vegetable Shortening | |
| Butter | Eggs | |
| Milk | Sour Cream | |
| Cream Cheese | Baker's cheese |
IN DOUGH, fats inhibit the formation of gluten by coating some of the flour grains, preventing them from absorbing water, which starts the gluten process. With less gluten, doughs become more flexible, more elastic and less sticky. In the baked goods, fat produces a tenderer crust and softer, more chewy crumb, and lengthens shelf life by slowing the rate of staling. In fact, the term "shortening" comes from the fact that fats actually shorten the gluten chains and shortbreads are, by definition, baked goods that are very high in fat.
Vegetable Oil
Although technically olive oil is a "vegetable" oil, as are palm, coconut, avocado and other fruit and kernel oils, vegetable oil, as used in this book, refers exclusively to the tasteless corn, cottonseed, safflower, sunflower, peanut, canola and blended commodity cooking oils sold in every food store throughout the land.
- As a tenderizer, nothing beats oil for the simple reason that, as a liquid, it's most quickly and completely absorbed by the flour. However, oil isn't very good at trapping air for the same reason that water doesn't trap air very well: it simply lacks the structural strength. For that reason, oil is best used in breads and sweet yeast pastries like babka and coffee cake, where there is enough gluten in the flour to produce the structure that supports the product.
- As a deep-frying medium, we recommend oils with smoke points greater than 400°F/205°C, i.e., refined corn, canola, peanut, and safflower oils. In addition, vegetable shortening, which is highly refined, also works very well as a deep-frying medium - if you don't mind it solidifying between uses. In addition, big box stores and bulk food outlets may also sell frying oil, which is specially formulated to resist breaking down at high temperatures.
- As long as you keep your frying temp at or below 350°F/175°C, you can expect to get 8-10 fries from your oil - even more from the frying formula - before it starts to go downhill. Just strain to remove solid particles and store it in a closed container at room temp.
Vegetable Shortening
Like vegetable oil, vegetable shortening - shortening for short - is colorless and virtually tasteless. However, unlike oil, it's treated with hydrogen so that it will solidify at room temperature.
Because of this inherent structure, shortening holds air beautifully, making it the preferred medium for creamed cakes, which depend on trapped air to leaven them, and for butter cream frostings, which achieve their lightness because of the large amount of air they incorporate.
Shortening's structure also makes it ideal for laminated doughs like puff pastry and Danish because it's so much harder for the flour to absorb than oil or water. Instead of becoming part of the dough, the shortening holds together and spreads out between layers of dough, creating the flakiness we expect. In cookies too, shortening coats the outside of the flour grains, inhibiting the absorption of water - and gluten formation - to a far greater degree than oil, producing cookies that spread least in the oven and dissolve in your mouth.
When buying shortening, it's important to always check the label, since manufacturers can add ingredients that affect the product's behavior. From a baker's point of view, the most important thing to look for is whether your shortening contains mono- and diglycerides, which act as an emulsifier that facilitates the combination of fats and water-based liquids and improve the quality of cake batters, but which can have a negative effect on butter creams and laminated doughs.
Butter
Many home bakers use butter because it tastes good and has a less negative public image than hydrogenated vegetable fats. Professional bakers, who are concerned with cost as much as with taste, are more likely to use a combination of shortening and butter, or 100% shortening plus butter flavoring to achieve the same results.
In fact, butter behaves identically to vegetable shortening, with a couple of notable differences. First, U.S. butter - along with its vegetable clone, margarine - contains about 20% water, as well as milk solids, flavorings, and sometimes salt, which means that a given volume of butter will have measurably less shortening power than an equal amount of Crisco or some other vegetable shortening.
European-style butters, which are increasingly available in the U.S., contain less water, about 14%-15%, making them easier to work with in laminated doughs like puff paste and Danish.
Cultured butter, which is also available in gourmet groceries and is produced by adding various strains of bacteria to milk in order to separate the butterfat, often have a strong, distinctive flavor that won't necessarily improve the taste of your baked goods; better to avoid cultured butters entirely and stick with the standard churned variety.
Eggs
To quote the advertisement, eggs really are incredible. Besides flour, no other ingredient has the greatest overall impact on the quality of baked goods, nor can any other ingredient match the number and diversity of the roles eggs play in breads, cakes, pastries and cookies.
Technically, when we refer to eggs in this book, unless otherwise specified, we're talking about either Grade AA or Grade A Large chicken eggs. One egg weighs about 1.75oz/50g without the shell, and consists of about 1.2oz/33g of albumin, or egg white, and about 0.55oz/17g of yolk. The white contains almost 90% water and about 10% protein, and the yolk is 50% water, 16% protein and about 34% fat. In bakers' formulas, yolks are considered fats and whites count as liquids.
In baking of all kinds, eggs perform a wide range of functions.
- In bread doughs, they moisturize and tenderize the crumb, retard staling and add the characteristic yellow color to challahs and enriched dough products like onion pockets and double-knot rolls.
- In cakes, eggs, whipped either alone or with sugar, incorporate air into the batter - in some cases, like classic sponge cakes and pound cakes, so much air that other leavening isn't needed. In recipes where aeration doesn't take place, eggs strengthen the structure of the crumb, as the proteins in the white and yolk combine with the starch in the flour to form the gelatinized lattice that surrounds the trapped bubbles created by the leavening and steam.
- In cookies, they often serve as the glue that holds the other ingredients together, while their dual fat/water nature allows them to emulsify the other fats and liquids in the formula.
- And in baked goods of all kinds, whole eggs, yolks or whites, applied as a wash to the crust before baking, helps toppings adhere to the dough and produce a rich brown, high-gloss glaze.
Milk
Milk is a highly complex ingredient. Liquid milk consists of varying proportions of water, fat, protein, bacteria, enzymes and a sugar called lactose. Although favored by home bakers, liquid milk, because of its bulk and perishability, was less common in the bakery.
Instead, bakers used dry milk, which is simply fluid milk from which the water - and in the case of nonfat dry milk, the fat - have been removed, either by vacuum-drying or with heat. Professional bakers prefer heat-treated dry milk because, in addition to evaporating the water, the heat kills any bacteria that are present, as well as destroying the enzymes, both of which can attack dough by weakening the gluten.
In baking, dry milk is used primarily as a crumb tenderizer and sweetener in breads, since yeast can't digest lactose - a fact that has the secondary effects of stabilizing fermentation and promoting browning because lactose caramelizes at the low temperature of 275°F/135°C. In cakes, milk protein binds to the protein in the flour, improving the structure of the crumb.
Sour Cream
One thing we could always be sure of finding in grandma's refrigerator was a tub of sour cream, which was a mainstay not only of Tevye's livelihood, but of the Yiddish diet as well. With sliced fruit or berries, slathered on a plate of kreplach (filled dumplings), potatoes - baked, boiled, or grated and fried into latkes - or stirred into a glass of borsht or the sour grass soup called shchav, it was a meal. As a special treat, we would sometimes eat it as shmetanas, a dairy hash of sour cream and pot cheese, garnished with generous pinches of chopped cucumber, radish and scallion.
In Jewish baking, sour cream is what makes a New York cheescake New York cheesecake. In sweet goods like sourcream cakes, short doughs and spritz cookies, its pleasant acidity tenderizes and whitens the crumb. It's important to note that formulas containing sour cream are always leavened with baking soda rather than baking powder, since the acid in the sour cream reacts with the sodium bicarbonate (baking soda) to form CO2; no additional acidifier is necessary. (For more information on leavenings, see the Leavenings chapter.)
Sour cream is made by fermenting heavy cream with lactic acid bacteria, which thickens and slightly sours the cream. In the U.S., full-fat sour cream contains from 18% to 20% butterfat and may also contain artificial thickening agents like gelatin, guar gum, carrageenan and/or rennin. A richer version of sour cream, called smetana, can contain as much as 30% butterfat and plays a similar role in the cooking of Central and Eastern Europe .
Cream Cheese
What's a bagel without cream cheese? Unheard of! Ridiculous! And yet, that combination was virtually unknown in Yiddish Eastern Europe, where bagels most often were eaten unadorned and cream cheese was virtually unknown.
In America, however, this mild-tasting, unripened high-fat cheese took Yiddish cooking by storm. On a bagel, it was breakfast. On rye bread with sliced olives, or white bread with jelly, it was lunch. Cream cheese quickly became the centerpiece of New York's best cheese cakes, rudely displacing the baker's cheese that had held that position in Europe. And nothing was - or is - better than rugelach made with cream cheese short dough. Just remember to soften the cream cheese thoroughly by beating it with the flat paddle before you add softer or liquid ingredients; otherwise, it will form lumps that don't dissolve during baking.
Like sour cream, cream cheese is made by fermenting with lactobacillus whole milk to which heavy cream has been added. The difference, however, is that in the manufacture of cream cheese, the fermenting mixture must be heated at a very specific point in the fermentation process to kill the bacteria and allow the coagulation of the cheese. To prolong its shelf life, commercial cream cheeses often contain stabilizers like guar gum and carob gum. According to the FDA, cream cheese must contain at least 33% butterfat (30% in Canada), with a moisture content of not more than 55%, and have a pH range of 4.4 to 4.9. In other countries, the fat content may be considerably higher.
Baker's cheese
Also called hoop cheese, pot cheese, farmer cheese and dry cottage cheese, baker's cheese is a mildly acidic fresh cheese made from skim milk, like cottage cheese and ricotta. It's used widely in Jewish cheesecakes and as a pastry filling. A key characteristic is its dryness: baker's cheese consists entirely of fresh curd, with no salt and little or no liquid added.
Another important characteristic is that it can be frozen and re-frozen without any loss of quality. Unfortunately, baker's cheese is virtually impossible to find at retail, and while no other cheese offers a perfect substitute, you can use Mexican queso fresco or cottage cheese which has been drained overnight in a cheesecloth-lined colander. Another good substitute is made up of equal parts of cottage cheese and well-drained feta cheese.
