It's time to have a real talk about baking fats. For some of us, butter was coined a "scary" or "bad" thing to consume There was a time where we believed our heart health was dependent on eating low fat/low cholesterol foods and we were ALL told to stay away from animal fats like lard and butter and eggs. What was perplexing at that time is we got creative and decided to make these miracle "fat-free" foods (see Olia chips) that were absolutely loaded with sugar and salt for flavor. Margarine became increasingly popular as a healthy alternative and a more heart healthy selection. It is an inexpensive, flavorful substitute that looks, and tastes very similar to butter. Its a great spread for your sandwiches but not something chemically you can just swap out for the real thing.
Hydrogenated vegetable shortening is a shelf stable, vegan, and inexpensive fat that has been a pantry staple for well over a century but is flavorless, dry, and acts nothing like butter. There are butter flavored shortenings that will add a strange hint of salty creaminess to your recipe but will lack that rich butter flavor note that people taste in quality baking.
These substitutes are great in theory, however, the fat listed in your recipe is there for a reason. The compounds that make it up, are lending themselves to the flavor profile, structure, and mixing of your batter or dough.
Please note: This post is only going to cover the four main fats seen in baking. The oils I am discussing are ones that do not alter the flavor (see: coconut or avocado oils). This post is not meant to be used for recipes doting "Ketogenic" or "Mediterranean" titles which have usually cleverly used healthier fat options flavors to their baked goods advantages.
So, what is it that fats do in baked goods exactly?
For breads and bread-like products it provides a lubrication that helps trap gasses that are emitted from yeast (a living leavening agent) to provide the air pockets that create the structure of the dough. It also adds flavor and acts as a preservative when breads are baked.
When baking quick breads or muffins, the fats are mostly for flavor and tenderness but the creamy texture of a fat will preserve the dough to keep it softer longer. Often these items use a liquid fat because they are mixed "all-in-one." This method of mixing does not use kneading or creaming to blend the dough but simply a folding in of all of the ingredients in one bowl. Because the fat is not creating the baseline for a strong structure, liquid vegetable oild will provide all the necessary tenderness for these products.
For cakes, the fat is one of the most important factors in how your cake bakes, how even your crumb is, and the density that is created. When you first blend your fat in a creaming method with sugar it is creating an emulsion that helps in creating air pockets in your batter. Sold fats like butters have larger crystals and will change the aeration (created when you beat the sugar and fat at a high speed, then add eggs and mix again) in the cake. To sum it up, the fat provides the main structure of your cake (although do not discredit that rich butter flavor in a well executed pound cake that melts in your mouth).
Finally, there are croissants, puff pastries, and Danish where the dough is a laminated fat and flour mixture and the fat provides crisp and flaky layers. Obviously, if you have ever attempted a lamination, you know those softer solid fats like margarine and shortening are far easier to work with than butter, especially on a hot and humid day where butter will simply ooze between the layers and create a weird pastry and a lot of mess. I have found that vegetable shortening and margarine can leave a greasy feeling on your tongue and miss the boat on flavor in these types of doughs.
What is the Difference Between Them?
Lets talk more about what these fats are made of.
Butter (most expensive, better flavor, and sourced from animals)
Butter is the grand marshal of flavor and structure in baking. A high quality butter is around 81.5% fat, 16% Moisture, and 2.6% salt. There are lower quality butters that have more salt or inconsistent fat content which causes them to foam a bit when they are melted. I really don't find that inexpensive butter affects my crumb or structure in my baked goods, so in my recipes, its OK to use the generic butters. If you are baking butterscotch or brown butter, I highly recommend clarifying your butter (this is the process of slowly melting the butter to separate it and removing the foam that builds on top gently). Butter also happens to cost around $3.00 a lb in the United States and with some recipes using 1-2 lbs of butter between baking and decorating, I can see why home bakers desperately seek out inexpensive alternatives.
Margarine (Moderate in price, similar flavor, and sourced chemically)
Margarine is a sneaky companion to butter. It often looks and tastes a lot like the real thing but varies in fat content and moisture. Margarine only has about 70-75% of fat, 20-25% moisture (hello, you super spreadable wonder paste), and 1-2% salt. With it lacking some of the fat needed to add structure, and having a higher moisture content it can be a terrible substitute when baking something like cake or cookies that need solid foundations. It can be used as a preservative in breads and muffins but you are risking extra moisture in your batter and if you are looking for a rich flavor profile it will fall short. It laminates well and if you are practicing puff pastry, Danish, or biscuits, it will fold well, not require copious attention to staying a certain temperature, and it will have a warmer melting point than butter.
Shortening a.k.a: Hydrogenated Vegetable Oil (Cheapest to buy, no flavor or artificial flavor, and doesn't require refrigeration)
Interestingly enough shortening is the term for any fat you can make pastry out of but the shortening you are used to seeing in the stores official namesake is: Hydrogenated Vegetable Oil and it has quite an interesting history behind it. It was originally created as a substitute for lard when making soap. Lard is the rendering from pork fat and is harder and more expensive to refine. Shortly after it was discovered to be a great alternative in soap making, it was in everyone's household under the name Crisco. This fat has no color, no added flavor and is almost 100% fat content. Vegetable shortening does no add moisture to a dough so cutting it into flours will produce a flaky tender crust. The most popular baked goods that use "shortening" are: Biscuits, pie doughs, puff pastry, and some breads. I personally use shortening to make fondant and to smear on my hands before I add color (it creates a washable fat barrier so the color doesn't stain your hands) in addition to the above uses. Again, I do not recommend using the flavored Crisco brand as a substitute for butter in a cookie or a cake because the high fat content will prevent the strong aeration needed to make those recipes work and the lack of moisture will produce a crisp, crumbly, and dry product. In breads, shortening will act as a preservative but add absolutely no flavor.
Vegetable Oils (A fully liquid fat, also inexpensive, the most stable, & no identifiable mouth feel in a baked product)
To be clear, the term vegetable oil is a blanket term for any two or more vegetable varieties blended together. This bottle of yellowish liquid will not only help with the structure when creaming a product, but it actually add moisture and a tenderness to a cake or muffins. It never foams so it can also be used in a bread dough (if you aren't making a yummy Italian bread that I would insist you use olive oil on). Almost always if a recipe calls for vegetable oil, there isn't a better substitute. If you try to find a healthier oil (like say coconut oil, or olive oil), there will be an undesired and very strong flavor to your cake or muffin and if you try to swap it out for one of the above mentioned oils with no moisture, your product will be dry,
So what about my vegan friends?
This gets a little tricky because butter is a tried and true animal fat and margarine (depending on the brand) can have milk incorporated into it. Vegan butter (margarine) is an acceptable substitute as it is formulated to act as much like butter as possible for products like cakes, cookies, and muffins. I strongly suggest you try a recipe that is meant to be vegan instead of swapping your own out as things may not blend exactly as you wish. As long as there is an egg substitute, any recipe using vegetable oil for these products would be fine as well. Pies and pastries are fine with shortening and I have had a lot of success in buttercreams (as long as they are kept cold, with vegan margarine.
And for those of you worried about eating a cake made with trans fats...
I have GOOD news
In most recipes (other than pie dough, danish, and pastry) the fat added isn't really that high per piece. For example: In my chocolate cake recipe, I add 1/3 Cup of vegetable oil to the batter. 1/3 cup of oil is actually a little over 2.6 oz in a batter thats total unbaked weight is 6.8lbs. It is only about 33% of the total cake. The cake makes about 10 servings and you are really only consuming 1/4 of an ounce of vegetable oil. My best guess with frosting is on most common recipes, you will only eat about 2 TBS of butter. Its also important to understand and appreciate everything in moderation.
Hopefully by better understanding these fats, you have a better understanding of WHY they can't just be swapped out. As far as trying to save money on butter, I have another pro tip: Butter is least expensive in the dead of summer and a few weeks before Thanksgiving and will spike in price during the month of December. If you are a holiday baker, keep an eye out shortly after Halloween for the buy 2 for $5 deals and coupons. If you see butter dip below $3.00, buy as much as you need for the season because if you wait, you may find prices will spike to almost $5.00/lb in some areas.
Happy Baking and Stay Tuned for More great Recipes and Facts