Fats are possibly one of the most controversial ingredients available to a cook or baker. Each fat has it’s up side and its down side. For our purposes here, I’m going to break this down into three basic types; animal fats, plant fats, and oils.
Before I get into the specific types, I’m going to give a brief overview of what it means for a fat to be saturated, unsaturated, or polyunsaturated. A saturated fat means that the whole chain of the fat molecule is totally straight. This creates a problem when our bodies are trying to break them down.
Think of the fats as magnets. If all the fats are totally straight magnets, it is going to be very easy for them to line up and stick together. This will make it much more difficult to break them apart since they are stuck together over a very long length. This is sort of the opposite problem of what we saw in sugars. Sugars that are easily to break down are bad, since they get stored as fats. In this case, fats that are easy to break down are good since we can use them as an energy source easier.
An unsaturated fat is a fat molecule that has one point on its chain that does not have a full set of bonds. Let me try and simplify that a bit. Fats have a structure that is made up of Carbon atoms. Each carbon atom is connected to 4 other atoms that are Carbon, Oxygen, or Hydrogen. What happens in an unsaturated fat is that one of the Carbon atoms is only connected to 3 other atoms instead of 4. Now I don’t want to get into the specifics as far as chemistry is concerned, but the fact that there are only 3 connections makes the lower part of the molecule stick out at an angle. Since part of the molecule is now sticking out, it becomes more difficult for the fat molecules to stick together. It’s like trying to get a bunch of bar magnets to stick together when half of it is bent at a 45° angle; you can probably do it, but they won’t stick together as strongly as they would if they were just straight. This means that our bodies are able to separate and break down the fats easier.
Polyunsaturated fats are the best! It means that the fat molecule is unsaturated in more than one place. This is the same concept as above, but now you have a bunch of fats together that are bent into all kinds of weird angles. If you had magnets like that, it would definitely be difficult getting them to stick together. As a result, our bodies have a much easier time breaking these bad boys down and using them as an energy source.
Animal fats are classified this way since they are made from animal products. The two most popular animal fats that you will encounter are lard and butter, both of which are delicious! Now, a lot of talk has gone into which types of fat are healthy and which ones are unhealthy. People have argued back and forth that animal fats are better, or plant fats are better. Personally, I am a fan of animal fats (at least as far as solid saturated fats are concerned) and this is for one reason. Aside from a few exceptions, animal fats are naturally present in their solid form, that is, they were solid to begin with and we did not have to do anything chemically to get them that way.
Butter is probably my preferred fat as a baker. The reason for this is because it has been created from milk. Since it has a basis in milk, it is not a pure fat so to speak, but it does contain all the goodness from the milk within the milk solids. Sure you can clarify your butter to get ghee, and cook with that. It is still delicious and has a wonderful clarity to it. I can see why some cooks prefer to do this, but as a baker I would never do so. Butter is, as I was saying earlier, naturally solid. Because of this fact, there is a mix of both saturated, unsaturated fats. Now, there is a lot more saturated fats than unsaturated fats (since it is a solid fat), but that’s okay, it tastes phenomenal. French bakers have used butter for centuries. It does not have the same ability to make pastries puff up as high-ratio shortening does, but sometimes it’s more about the taste than the presentation. Besides, as I’ve said before, if we’re going to do something, let’s do it right!
The other animal fat that you can use is lard, which is rendered from Hog fat. This is a pure fat and seems to have a nearly infinite shelf life. While not as delicious as butter, it has the ability to be heated to a significantly higher temperature without smoking since it doesn’t have those pesky milk solids that tend to burn. For a long time, lard was actually used in deep fryers at McDonalds for those delicious golden fries. It actually amuses me a little bit when they do their experiments on how long the fries will last. Of course they will last for months without going moldy, they are so deeply embedded with delicious fats that they have an anti-mold shield in place. Anywho, you will also find lard in use at old school bakeries and donut shops. The reason why you cannot duplicate their exquisite taste is most likely a result of the fact that you probably wouldn’t use lard in your products. Is lard worse for you than butter? You bet! It’s made up of completely saturated fats, but at least it is from a natural source. One of the things I will get into later is the difference between long chain and short chain fats.
Okay, so in plant fats, well, solid plant fats, we have shortening and margarine. Shortening and margarine are pretty much cut from the same block, except, like the difference between butter and lard, there is water in margarine. I think that the original argument was that margarine is better for you than butter since it is made from the goodness of plant oils, canola, olive, etc. The problem, however, is that in order to go from oil to a solid fat, it was necessary for the creators to artificially saturate the fats (called hydrogenation). So as we were talking about in the beginning, polyunsaturated fats are essentially oils. Their structure is so bent out of shape that they are unable to stick together, thus they simply float around in oil form. What hydrogenation does is to force Hydrogen atoms onto the Carbon atom that only has 3 bonds to make it bond to a 4th atom. Thus, the chains straighten and create a solid fat. Woohoo! The only problem is that hydrogenation will take a polyunsaturated fat and turn it into a saturated fat. Now we have a fat that is extremely difficult to break apart, and is now bad for your health (just like lard).
The last thing I want to mention about margarine is that it essentially has the same amount of fat as butter. Now you may have seen a lot of reduced fat or zero fat spreads out there. While these are fine for putting on your toast in the morning, you definitely do not want to use them as a baking substitute. The reason why the spreads are lower in fat is because they contain significantly more water. Basically you’re just paying for them to add water to your product. These spreads are able to maintain their shape only because gums have been added to them to maintain their cohesiveness.
The exception here is coconut oil. Coconut oil is actually solid at room temperature (well, depending on your room temperature…). There was a controversy recently regarding the use of coconut oil. A lot of “experts” were saying that it is bad for you due to the large amounts of saturated fats. True, I agree that there is indeed an alarming amount of saturated fats contained within it, however, these fats are actually short chains. Plants and animals will tend to create long chain and short chain fats. Basically, the chain length will be determined by however much glucose the organism chooses to add onto each chain. The difference however is to look at what it would be like to pry apart bar magnets that are two inches long versus bar magnets that are 12 inches long. It is much easier to break apart a small one versus a large one, and the same is true with these fats. A good way of seeing this for me was the fact that during the winter, when the house is about 70-74°F, the jar of coconut oil is solid. During the summer, however, when the house it at about 76-78°F, the jar was completely liquid. It really does not take as much energy to break apart the fats in coconut oil versus the other solid fats.
Oils, as I was saying earlier, are just unsaturated, or polyunsaturated fats. As with everything, unless you specifically purify it, there will be a crossover of color and flavor. Just look at the light green, strongly flavored Olive Oil, and the yellow barely flavored Canola Oil. There is a huge amount of oils available to you, from nuts oils, to vegetable oils. Whichever one you choose will depend on your preferences and needs. Just be aware that if you choose to use a strong oil, like sesame oil or truffle oil, a very little bit will go a long way.
When cooking, oil is your friend. It is easy to coat a pan, or pot and can be heated to very high temperatures. Some of the specialty oils are so expensive that they are generally not used in large amounts. Instead they are often used as finishing oils or inside salad dressings. Other oils tend to smoke at a low temperature and are usually not used for cooking. Peanut oil, canola oil, vegetable oil and corn oil are all very stable oils that are, or were, commonly used in the industry.
When baking, oil is sort of your sketchy friend. Sometimes it comes through for you, and sometimes it does not. For example, Oil can be an easy substitution into a fluffy cake recipe (just look at pancakes), oil is even used in small quantities in making bread. Do not, however, use oil in cookies or any baked product that needs its fat source for leavening, like a puff pastry.
How do Fats Work in Baking?
I think the biggest thing that people normally wonder about is that nice flaky crust on a pie or pastry. While a lot of this is a result of proper methodology, the type of fat we use also has a lot to do with it. You may have seen that a normal pie crust recipe directs you to break up the fat into small pea sized pieces. When you roll out the dough, these small pieces actually flatten out and create little flattened blobs of fat in the dough. When you bake your crust, the fat will create a shield on the top and bottom of a layer. The evaporation of the water in the crust and create steam this will cause the dough to puff up. Since parts of the dough are shielded because of the flatten disks of fat, they will create little air pockets. The areas that are not shielded will absorb the water and then dry out. All of these little air pockets throughout the crust is what we refer to as flakiness.
The second thing that you may be wondering about is the role of fat in cookies. When you are making cookies, the fat will coat the pieces of flour and sugar and make a nice crumb since they are kept in little separate pockets. Now this is the key that I like to tell people. The more you mix your cookie dough, the more they are going to spread out. I have seen people walk away from the mixer and they end up with little cookie crepes. The reason for this is quite simple. As you mix the fat into the cookie dough, it begins to coat the particles. As you continue to mix it, more and more particles will get coated. This is okay, however, once too many particles are coated, they lose their ability to stick together since gluten strands are unable to form. Whenever I make cookies, after I add the dry ingredients, I mix it just until things are pretty much incorporated, then I finish it off by hand.
How does Fat Work in Cooking?
Let me just say that as far as cooking is concerned, fat is a beautiful thing. Without fat, cooking would be rather bland and have a slightly unpleasant texture. Primarily, we use fats, oils in particular, to coat pans or pots so that food won’t stick to them. We also end up using fats to add flavor, such as a nice brown butter to toss pasta or spaezle in.
This next example goes back to baking a little bit, but it is for a savory dish. You will notice that when you are done making chicken stock you have a nice layer of fat on the top. DON’T THROW IT OUT!!! In addition to the fact that this is pure fat, it also tastes quite good. If you are thinking of making a Quiche or some sort of stuffed pastry for dinner, use your left over chicken fat! I did this several times while I was working at a café and people loved it. If you are now cringing at this fact, let me just say that my years working in the restaurant industry has taught me that the reason things taste so good, is because they are totally loaded with fat. YUM!
Another example would be if you have rendered off some fat, say from the leftover chunks of fat from butchering a leg of pork. Just melt it down and add it to a dish for some intensely good flavor. When I was in culinary school we were making a pork stew, I forget what it was called, but it is a French Canadian classic. Anyhow, I just couldn’t get the full bodied flavor I wanted, so I poured in about ½ a cup of rendered pork fat. Talk about amazing! Of course I did this a little bit wrong. Technically I should have used the fat to make a roux, and then use that to thicken the stew. Either way, you can maximize the money you spend on food by utilizing all the parts. It also gives you a great flavor that may actually remind you of the cooking you remember when you were young.