周老師的美食教室英文版

1. Cream of Tartar (Potassium Hydrogen Tartrate)

Many cake and candy recipes require the addition of cream of tartar. Cream of tartar is a byproduct from wine making. It occurs naturally as a weak tartaric acid crystal form while the grape juice ferments in the barrels. Tartaric acid combines with other chemicals in grape juice to form mild acid salts. One of the salts is potassium hydrogen tartrate or cream of tartar.

Cream of tartar is a harmless and safe additive which primarily is used as an acid in different ways. For example:

1. Making baking powder when combined with baking soda.
2. Stabilizing the alkalinity of whipped egg whites so it won’t deflate easily.
3. Preventing cane sugar from crystalizing when making candy or fondant.
4. Making invert syrup or trimoline. The acidity converts sucrose (table sugar) into glucose and fructose.
5. Whitening the color of steamed buns and baozi.

The most common use of cream of tartar is actually number 2: stabilizing whipped egg whites in cake recipes that use the egg white and yolk separately.

People often ask: is it necessary to add cream of tartar in a cake recipe?

Egg white is alkaline, so whipped egg white usually has a tint of yellow color with a slight soap taste. Cream of tartar can correct both of these problems.

Since a cake has many ingredients other than egg white, alkalinity is not such a big problem once everything has combined. Cream of tartar is not critical here. Based on my experience, cream of tartar should be used when making angel food cake because it contains high ratio of egg white but no egg yolks or other types of fat. Without cream of tartar, the cake just simply tastes off. Other cakes usually don’t have this kind of problem when cream of tartar is left out.

Cream of tartar is safe to consume and the amount needed in a recipe is minimum. For example, less than a teaspoon (3.2 g) is typically added to a cake. If the recipe calls for it, feel free to use it.

If you don’t have cream of tartar in your pantry, you can substitute it with lemon juice or white vinegar, but these substitutes will not work as well as cream of tartar.

Regarding usage number 5, cream of tartar can make the steamed buns and baozi whiter. Again, lemon juice and white vinegar can do the same. In my early days of teaching, I often used vinegar to whiten the steamed buns/baozi when students complained about the yellow color.

I rarely use these three products to whiten the steamed buns/baozi nowadays (although it is no big deal to use them) because 1) a lot of flour on the market is bleached and 2) students’ biggest complain isn’t really about the color of the steamed buns/baozi but how the surface of them isn’t smooth.

Homemade steamed buns/baozi usually have wrinkly surface because the dough isn’t pressed with a pasta press, dough isn’t rounded to shape properly, dough is overly fermented, the steam is too strong during steaming, or the steaming baskets are fitted too tightly.

People usually complain wrinkly steamed bun/baozi look yellowish but once the surface is smooth and shiny, the color is overlooked and becomes very natural.

Note: an acid usually is capable of whitening the food and a base (alkaline) can darken the appearance of food. The acidity and alkalinity in our discussion refer to the natural taste of food. Most food is usually acidic while egg white, thousand-year-old egg, and baking soda are alkaline (noodles and other starchy products with potassium carbonate added are also alkaline).

We will not discuss how food after being metabolized will affect blood’s pH value. For example, an orange contains acid is actually an alkaline food.

1. Baking Soda (Sodium Bicarbonate)

Baking soda is a weak base. It has two major uses in cooking:

1. Breaking down proteins. Baking soda is a meat tenderizer. Many restaurants marinate the meat (e.g. black pepper tenderloin dish) with baking soda in order to cut down cost or avoid buying top quality meat.
2. Neutralizing acids. Baking soda creates carbon dioxide when it neutralizes an acid. It is a leavener in cakes.

There are two main types of cakes: shortened (butter or oil) and unshortened (foam) cakes. Shortened cakes usually start with whipping the butter and sugar; unshortened cakes usually start with whipping the eggs and sugar.

Shortened cakes must contain a good amount of butter while the unshortened cakes contain a good amount of eggs to incorporate enough air to make the cake soft and airy. If the amount of fat and egg is to be reduced, a leavener must be added in order to produce additional gas to lighten the cake. Before the invention of baking powder, baking soda is the only leavener for cakes.

Experienced bakers have discovered that baking soda only has leavening power when it is used with an acidic ingredient like yogurt, lemon/orange juice, brown sugar, or honey. If there isn’t an acidic ingredient in the recipe, you can add a couple of tablespoons of white vinegar. Otherwise, the unreactive baking soda will not lighten the cake but to leave an unpleasant bitter or soapy taste in the mouth.

I have always felt many chocolate cakes taste soapy and thought chocolate must be alkaline to contribute to it. It was not until later did I realize these soapy tasting chocolate cakes had too much baking soda in them without an acid to neutralize it.

Some baking texts say that baking soda is used to balance out the acidity of the chocolate. It is really not the main reason because chocolate is not particularly acidic and humans are more receptive to acidic than basic taste. Lemon cakes don’t need baking soda, so why would chocolate cakes need it?

Many chocolate cakes on the market usually contain baking soda because it makes the chocolate cakes look darker without using too much chocolate to cut cost. Some bakers even add black food coloring in addition to baking soda in chocolate cakes and brownies. Forgive me but I think these blackened cakes are no longer beautiful and have lost all visual appeals.

Baking soda should be stored in a dry cool place or it will lose its potency. Here is how to check: take a little bit of baking soda then add about 8 times white vinegar in a bowl, bubbles should form immediately. Otherwise, the baking soda has lost its potency.

Note: there are many folk remedies involving the use of baking soda. For example, pain reliever, cleaning solutions, washing vegetables/fruits, or even washing the face with it. Although it is non-toxic but it doesn’t mean it works with everything. Baking soda can only neutralize an acidic pesticide. You should ask for a medical doctor’s advice if you plan on ingesting baking soda as a medication.

III.Baking Powder

Baking powder is now the most common leavener for cakes.

Baking powder is made from combining baking soda and cream of tartar. Baking soda and cream of tartar neutralize each other when moisture is added to release carbon dioxide.

In the early days, baking powder and cream of tartar were packaged separately to prevent them from reacting with each other too early if they get wet. With the advanced packaging, air moisture is no longer a concern of making the baking powder reactive but some corn starch is still added as a buffer to absorb moisture.

Baking powder is more neutral than baking soda and it works well when there isn’t enough acid in the recipe. Most of the cake recipes now use baking powder rather than baking soda.

Baking soda and cream of tartar usually reacts very quickly to release carbon dioxide once water is in the mix. So a good leavener like baking powder should not only be able to release gas when it reacts with water but also release additional gas when it is heated. This is a double-acting baking powder. This type of double-acting baking powder is what’s sold on the market.

Double-acting baking powder works because it contains several acid salts. One of the most effective is aluminum salt (like borax). This is the reason why people question about the safety of baking powder but not baking soda.

Aluminum has been linked to the cause of Alzheimer’s disease. Many people have been avoiding using anything that contains aluminum like aluminum pots and pans.

Some companies now have “baking powder without aluminum” to address consumers’ concern but it doesn’t work as well as the regular baking powder according to users who have visited my blog. Since aluminum salt is the most effective way to make the double-acting baking powder, it is like using fast-acting baking powder (baking soda + cream of tartar) without it.

Some bakers are using “homemade” baking powder. It is basically baking soda with cream of tartar or substitute milk with yogurt then add baking soda. None of the above will work as well as the double-acting baking powder. If you prefer to use the fast-acting baking powder, you need to bake the cake immediate once the baking powder has been added to the cake batter; otherwise the carbon dioxide would have escaped out of the batter.

Too much baking powder in the cake will give it a bitter taste. Here is a simple formula to gauge how much baking powder is needed in the recipe: 1 teaspoon (4 g) to a cake batter with 1 cup of flour + 1 cup of fluid + 1 egg. Baking soda should be ½ - ¼ of baking powder used in the recipe (1 teaspoon of baking soda is about 4.7 g).

Baking powder should be kept in a dry cool place or it will lose its potency. Here is how to check: sprinkle 1 teaspoon of baking powder in half a coup of warm water. If it bubbles immediately, it is still good to use.

Chinese pastries usually use ammonia bicarbonate (baker’s ammonia) as a leavener. It works well to produce gas but the byproduct is ammonia. Ammonia reacts with water and leaves a foul smell in recipes that call for large quantity of water. Therefore, ammonia bicarbonate is only used in pastries like the fried dough or walnut pastry that require small amount of water along with some baking powder or baking soda to achieve the leavening effect.