KitchenSavvy

Beating Egg Whites - How Cream of Tartar Helps

While you mentioned that cream of tartar, in a properly sealed container, can be kept indefinitely, I used mine last evening and the beaten egg whites did not turn out to be stiff as described in the recipe.  I suspect the culprit is my cream of tartar being too old, even though it was kept in a tightly sealed container.

-- Lucy

Cream of tartar does not affect the stiffness to which egg whites can be beat nearly as much as it helps stop beaten egg whites from collapsing. 

When you beat egg whites, proteins in the whites unfold from their natural shape and become tangled with each other.  At the same time, you are beating air into the whites, forming small bubbles.  The protein molecules become attached to each other through chemical and electrical bonds that reinforce the skin of the air bubbles.  Over time, these bonds can pull the proteins closer together, forcing out the water trapped in the surface of the bubbles.  Eventually, the proteins pull themselves together so strongly that compact, grainy protein lumps form and the liquid pools in the bottom of the bowl.

This is where the cream of tartar comes in.  It helps prevent the formation of chemical bonds between protein molecules.

To understand this, first a little chemistry.  Protein molecules have, along their length, sulfur atoms that in turn may have a hydrogen atom attached.  If the sulfur atoms release their attached hydrogen into the surrounding liquid, then they can attach to something else.  Sometimes, that something else is a sulfur atom on another protein molecule.   If too many sulfur - sulfur bonds occur, the proteins pull together too strongly and the foam collapses, as above.

Because it is acidic, the cream of tartar increases the number of free hydrogen atoms in the liquid.  These extra hydrogen atoms either stop the sulfur atoms from releasing their attached hydrogen, or else provide another hydrogen atom to quickly take its place.  Because of this, the rate at which sulfur - sulfur bonds can be created is slowed down enough to help keep the egg whites stiff long enough to be used.

Any acid can be used for this purpose, although cream of tartar and lemon juice are the most common.  The amounts needed are 1/8 teaspoon per egg white for cream of tartar and 1/4 teaspoon per egg white for lemon juice.

If you are having trouble beating egg whites to stiff peaks, there may be one of three causes.  If you got any of the yolk from the eggs into the whites while separating them, this can lessen the ability of the eggs to form stiff peaks, as can contamination from oil, fat or detergent on the utensils.  You should never use a plastic bowl to beat egg whites, since fat molecules are attracted to some plastics and may leave a film on the inside of the bowl.

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If you have food or cooking questions, send them to Questions@KitchenSavvy.com

If you have food or cooking questions, send them to Questions@KitchenSavvy.com

Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Substitute for Gruyère Cheese

What can I substitute for Gruyère cheese?

-- D

To some extent, that depends on what you are using it for.  In fondue, Ememental would be the standard substitution.  If you can't find Emmental, look for generic Swiss Cheese.   The Food Substitutions Bible suggests you can also use Comté or Beaufort as a general substitute for Gruyère.

For melting on top of one of my all time favorite potato dishes, Potato Flan with Caramelized Onions, I really like Jarlsberg, since its slightly stronger, nutty flavor stands up well to the complexity of the dish.  The original recipe called for Gruyère.  For grilling or melting onto potatoes or vegetables, you could also use Raclette from France or Switzerland.

And for eating out of hand, try any of the above as well as Maasdam or Edam.

If you live somewhere that has a good, knowledgeable cheese store, like the Bulk Cheese Warehouse in Saskatoon, go in and tell them what you are making.  They may have many more interesting suggestions.  If you are looking for a cheese to go with a particular food, say maybe to serve alongside a Peach Cobbler, tell them.  They may be able to suggest an interesting pairing.  If you aren't sure of a recommendation, most cheesemongers will be happy to give you a taste of any cheese they suggest.

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Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

How Can You Prevent a Cheesecake from Cracking?

How can you prevent a cheesecake from cracking?

--Sr. Celine

Cheesecakes crack because the filling expands during cooking and then contracts while it cools.  If the filling is not able to relieve the stress caused by this contraction in some way, it cracks.  There are a few ways to help prevent cracking, according to Harold McGee.  They come down to ways to either reduce expansion or allow the filling to contract more uniformly.

To reduce expansion start by not over mixing ingredients.  The longer the ingredients are blended, the more air is incorporated, which expands during cooking, causing the filling to expand.  If you are using an electric mixer, use the lowest speed possible to do the job.  The downside, though, is that the resulting cheesecake may be more dense.

Also, cook the cheesecake at as low a temperature as possible.  A longer cooking time means more time for bubbles to escape.  If you can, use a water bath to moderate the cooking temperature.  If you are using a springform pan in a water bath, place the pan onto two or three layers of aluminum foil and then bring the foil up around the outside of the pan to keep water out.  The water bath may extend the cooking time, but it is the best way to cook egg custards, like cheesecake.

To get the filling to contract uniformly after cooking, do not overcook the cheesecake.  Shirley Corrihersuggests that there should be an area about three inches (7.5 cm) in diameter in the middle that is "still wobbly and shaky and ... looks undercooked."  For a more accurate estimate, use an instant read thermometer.  Insert the thermometer, starting at the corner edge so as not to poke a hole in the top of the cheesecake, angling down and in so that the tip is close to the center of the filling.  For food safety, eggs should be cooked to 160°F (71°C), however too much above that and the filling may start to separate and become grainy (see the KitchenSavvy posting Custards and Sauces).

If you are using a water bath, you can cook the filling to about 145-150°F (63-66°C), remove the cheesecake from the oven and allow the cheesecake to remain in the water bath, out of the oven, for another hour.  During that time residual heat will finish cooking the filling until it has reached the desired temperature.  If the temperature reaches 155°F (68°C) before you take the cheesecake out of the oven and you are using a water bath, remove the cheesecake from the bath and allow it to cool on the counter.  If you didn't use a water bath at all, cook the cheesecake to 155°F (68°C).  In either case, heat transferred from the edges to the center will finish the cooking to a safe temperature.

Cooking to a higher temperature, or until the center is no longer wobbly makes the filling less elastic, and more likely to crack.

Once the cheesecake is cooled to lukewarm, cover and refrigerate.

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Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Creaming Butter II

My wife says I have to cream butter and sugar with electric beaters in one direction only. She says this will help incorporate the air into the mix and make it creamy.  I seem to be getting results moving the beater through the mix ad hoc. Is there any science to beating in one direction for the purposes of creaming butter?

--Ling

Because of its complexity and the fact that cooking has evolved over thousands of years, it tends to be filled with both sound, provable science and popular folklore.  For example, one similar "rule" is that you need to stir in one only direction when making a custard and that changing direction or  whisking in a random pattern will cause the custard to curdle.  I can say with certainty that the custard thing is false, because I never bother to stir in just one direction and my custards don't curdle.

I know of no science that would either support or disprove your wife's theory but looking over my various references, I can't find any that say creaming needs to be done by beating the ingredients in only one direction.

On the face of it, I also can't think of any good reason why it would be so.  As I explained in the posting "Creaming Butter" the purpose of creaming is to incorporate air into the butter to help leaven the final product.  According to Corriher, creaming is perhaps the most important step in making good cakes.  Air bubbles are incorporated both from the air trapped between grains of sugar when mixing starts, and then by air blended in by the mechanical action.  Neither of these would appear to depend on what direction the beaters move during blending.  In fact, at the level of the beaters, regardless of how you move your hand, one blade is going clockwise while the other goes counterclockwise!

To test whether the direction of beating makes a difference, you would need to compare cakes made by creaming the butter by beating in only one direction versus cakes made when the beating is in random directions.  You would need to be careful to control every other aspect of the cakes -- the ingredients would need to be accurately measured, the butter would need to be at the same temperature starting and ending, and the beating time would need to be the same duration.  The cakes would then need to be cooled to the same temperature and under the same conditions.

After all of that, what I'm guessing you would learn is more likely that there are so many steps, involving so many factors, that ascribing differences in the result to the direction in which the butter is creamed is too simplistic.

The bottom line is that if your "ad hoc" beating technique produces good cakes, then you have shown that direction doesn't matter.  Now, go and enjoy your cake.

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If you have food or cooking questions, send them to Questions@KitchenSavvy.com



Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

How to Tell if Eggs are Fresh

I have a carton of eggs without a best-before date on it.  I think I have had the eggs for about two or three weeks.  Is there any way to tell if they are fresh?

--Lin

There are two ways to tell how fresh your eggs are, but you need to remember that these are rough guidelines and that they don't necessarily tell you if the eggs are safe to eat.

The first method is to fill a container with cold water.  If your egg is fairly fresh, it will sink to the bottom of the bowl and lay on its side, maybe tilted a little toward the rounder end up.  As the egg gets older, it loses moisture and the air sac inside the rounder end enlarges.  A somewhat older egg may still sink to the bottom of the bowl, but will rest on the pointy end.  If the egg floats with the round end slightly above water, then it is old and should be discarded.

The container needs to be deep enough that you can clearly see if the egg is submerged, touching the bottom, or floating.  A four cup (one liter) glass measuring cup is ideal for this test.

If you were planning to crack the egg anyway, you can also tell the freshness by emptying the egg onto a flat dish, such as a side plate.  If the egg is completely fresh, the white will stay together and mound up noticeably around the yolk so that it clearly can be seen to have two levels.  The yolk will be rounded and well domed.  As the egg get older, the white becomes more runny, spreads more on the plate and doesn't rise around the yolk.  The yolk also becomes flatter.  If the white is watery and shows little or no rise in level around the yolk, then the egg is quite old.

As I said above though, these are tests only of the age of an egg and don't tell you about the safety.  improperly stored eggs can be contaminated and still pass these tests.  For safety, always try to be sure and buy eggs in a carton with a clear date, keep them in the carton, and don't move eggs from one partly used carton into another.  Always use eggs before the best-before date.

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Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Crunchy bits in Parmesan Cheese

I notice in Parmesan cheese sometimes that there are crunchy little grains.  What are they and what causes them?  Do they mean that the cheese is no longer good?

--Anja

The grains you are noticing are crystals of either calcium lactate or the amino acid tyrosine.

Tyrosine is formed by the breakdown of proteins in the milk.  It precipitates out as crystals as the cheese loses moisture, rather in the same way that crystals form in a sugar water solution as it cools down.

Calcium lactate crystals are formed by the bacterial conversion of lactic acid into a mirror image form during ripening.  In either form, lactic acid will chemically bond with the calcium in the milk to form calcium lactate.  Because the mirror image form of lactic acid is less soluble, it precipitates out and forms crystals.

I recently encountered the same crystals in a delicious cheese called Beemster that I got at the Bulk Cheese Warehouse in Saskatoon.  Beemster is a Dutch Gouda-style cheese that has been aged for 18 to 26 months or longer.  It is sometimes referred to as Extra Aged Gouda.  The taste is somewhat like Parmesan, but with a caramel, nutty flavor slightly reminiscent of Gjetost.  The texture, however, is more buttery probably due to a fat content that may be nearly twice as much as that of Parmesan.

Other softer cheeses may also form crystals due to changes in the acidity of the cheese.

These crystals are a normal phenomenon, and do not mean that the cheese has gone bad.

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Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Difference Between "Free Run" and "Free Range" Eggs

At the grocery store recently, I bought a cartoon of what I thought were free range eggs.  When I got home, I noticed that the package said "free run."  What is the difference?

--Glenda

Eggs can come from hens that are 'free range", "free run" or "battery".  The image people are most familiar with is that of "battery hens", crowded into cages with very little room to move.  Feed is placed in a trough at the front of the cage and eggs that are laid roll across the sloped floor so that they can be easily gathered.

On the other end of the spectrum is the idyllic thought of hens free to roam about the great outdoors, pecking their food from the ground and nesting where they wish.  This is the "free range" chicken.

Between these two is the "free run" hen, which is given the freedom to move about an enclosed barn and provided with nesting boxes in which to lay eggs.

In practice, many free range chickens, while they may have access to the outdoors, still rely on the shelter and safety of the barn and so are more like free run chickens than the mental image suggests.  In colder climates, such as Canada, hens are only able to be free range for part of the year.

While free range and free run eggs come from chickens that are handled in a more humane fashion, they are more difficult to gather and may have been laid in less sanitary conditions, making the labor costs and spoilage factors higher than for battery chickens.  This accounts for some portion of the increased price for these eggs.

There is little or no oversight of the industry to make sure that packing claims reflect actual conditions.  Nutritionally, the eggs from all three sources are quite similar.

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If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Keeping Easter Eggs

How long can you keep boiled easter eggs without refrigeration?  How long can you keep boiled eggs in the fridge?  Please, we need this answer A.S.A.P.

--Ed

I assume when you ask how long can you keep boiled Easter eggs without refrigeration, you mean ones that you intend to eat afterwards.  If so, then the general food safety rule holds.  Cooked food should be kept no more than two hours at room temperature.   You may think that the shell will provide some extra safety, and therefore more time, but when it comes to food safety and the health of family and friends, it is always better to err on the conservative side, so stick with just two hours.

According to the American Egg Board, hard cooked eggs still in their shells will keep in the fridge for up to one week.  If they are peeled, they should be kept in the fridge for no more than three days.

If you store hard boiled eggs in the fridge, you may notice an odor from the outgassing of hydrogen sulfide formed during the cooking.  The odor will dissipate in a few hours and does not necessarily mean that the eggs were bad, assuming they were not past their "best before" date.

In any case, if you are dyeing the eggs first and then plan to eat them, be sure to use only food safe dyes.  Regular food coloring works well for dyeing eggs.

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Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Discoloration of Egg Yolks

How do I keep an egg from turning dark inside when it is hard boiled?

--Raymond

The gray-green ring that forms around the yolk of a hard-boiled egg is the result of iron in the yolk combining with sulfur compounds to produce ferrous sulfide.  There appears to be some question as to whether the sulfur comes from the white or whether the yolk itself has sufficient sulfur to cause the discoloration to happen.  In any case, the reaction is encouraged by heat.  The colored ring is harmless.

To avoid having this happen, use the freshest possible eggs (see the post Peeling Hard-Boiled Eggs if you plan to peel them), do not over-cook the eggs, and if they are not being served right away cool them down in ice water to prevent continued cooking once they are taken off heat. 

As always, I recommend the Norpro Egg Rite Egg Timer to get eggs cooked to perfection.

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If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Crème fraîche

What is crème fraîche?  I have several recipes that call for it but I can't find it anywhere.

--Eva

Crème fraîche [pronounced 'krem FRESH'] is a common ingredient in French cooking.  It is a fermented cream product with 30% or more butter fat, by weight, and is used to garnish soups or desserts.  It is also used as an ingredient in sauces, and may be incorporated into cheese cakes.  Crème fraîche is somewhat thicker than American sour cream and has a distinctly nutty and tangy flavor.

Because cream products in the United States and Canada are pasteurized, it is not easy to get an authentic crème fraîche, which is made from raw milk.

In some recipes, particulalry sauces, you can substitute commercial yogurt or sour cream thickened with a small amount of corn starch, but for a more accurate taste and texture, especially when it is used as a garnish for fruits or other desserts, try combining two tablespoons of buttermilk with one cup of whipping cream.  Store in a sealed, sterilized jar for 8 to 24 hours at room temperature.  The longer you leave it, the thicker it will be and the more the flavor will develop.

After that time, your crème fraîche can be stored in the refrigerator for up to a week.

Crème fraîche is not suitable for whipping.

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If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward