Recently I wrote a post comparing and contrasting margarine and butter nutritionally. (If you haven't read it you can check it out here: Health Tips: Margarine vs Butter.) While I thought that was a good start on the topic of which is better to use, it didn't consider a factor near and dear to my heart, and I assume the hearts of my readers--which is better for baking?
As I said in my health tips post, I grew up using margarine. When I left my mother's kitchen and started baking on my own, I continued to use margarine in recipes that called for butter. I noticed over the years that things such as cookie dough were so sticky that they are almost unmanageable. For a long time I was frustrated and thought maybe I just was just doomed to baking failure. But after doing some reading on the subject, I decided to do something radical. I tried butter. I could not believe the dramatic results. I found that dough made with butter is much firmer and easier to handle. Why you ask? (I know you are asking!)
It turns out there are two big differences between margarine and butter that explain their different baking properties. One is the water content of the two products. Butter is about 18% water and 82% fat. Margarine is about 50% water (depending on the brand) and 50% fat. If you consider a recipe that calls for a significant amount of butter and substitute margarine, you are adding much more water to the recipe, and the increased moisture will make it stickier. For example, if a pie crust recipe calls for 1 cup butter, using 1 cup of margarine would include adding 1/2 cup of water. Using butter would include less than 1/3 cup of water. Of course, stickiness can be combated by adding additional flour, but that can result in a final product that is overly tough.
The other factor at play is the type of fat in the two products. Because margarine is made of vegetable oils, it is primarily unsaturated fat. Butter is an animal fat so it is primarily saturated fat. What's the difference? (You have so many good questions today!) Saturated fat is solid at room temperature whereas unsaturated fat is liquid. That is why the oil in your cupboard is liquid, but the fat you drained off last night's browned hamburger is now solid. So, the solidity of the fat in butter results in a more solid dough when it is used instead of margarine.
I know your final question now is, "What does this all mean?" Well, I think that for most baking purposes, butter seems to be the way to go. This would especially be true for items that require a lot of handling, such as sugar cookies. It is also true for pastries, such as pie crust, where the proportion of fat to other ingredients is important for proper results. With that being said, I have had success using margarine in recipes where stickiness doesn't matter, such as cake batter. Margarine could also be used in recipes where the amount needed is fairly small as the moisture difference would not be significant.
There. You learned something today! I hope you now feel a little more confident about conquering the foodie world. Happy baking!