The perfect cookies, the best sandwich loaves, the tastiest muffins— all of these require butter, oil, or shortening, and sometimes different recipes will tell you to use one instead of the other.
So what are the advantages of each? When is it better to use butter or shortening as a substitute for oil or vice versa? This article will tell you when and how to best to use each one and when and why they might not work for specific recipes.

Our Preference
We admit to a prejudice for butter. We love the flavor of butter and we avoid the hydrogenation in shortening. By melting butter, we can substitute butter for oil in most bread product recipes—though we admit to making plenty of muffins with oil instead of butter.
There are some products—many pastries for example—where only butter will do. We love to use olive oil in some of our breads. (Olive oil is a healthier oil that we like to use where the flavor is appropriate.) But in many baked goods, you can choose which fat product you want in your breads, cookies, or muffins.
Yeast Breads
Substituting Butter For Oil Outside of the Bread Machine

If you are making breads outside of a bread machine, you have a lot of latitude. Melted butter can be substituted for oil. You will get the flavor of butter with most of the tenderizing effect of oil.
Unless you use unsalted butter, the butter will add a touch more salt, but it’s unlikely that you will be able to tell. Breads made with oil tend to keep a little longer than breads made with butter instead.
If you use melted butter, let it cool until it is warm to the touch. Hot butter above 140 degrees will kill yeast upon contact. If you are adding enough warm butter to affect the dough temperature, the heat will accelerate the yeast growth.
Substituting with Olive Oil in Bread
We use olive oil in nearly all of our savory breads—it adds a rich flavor that is incomparable. We keep our olive oil refrigerated to stay as fresh as possible. But cold olive oil creates the opposite problem of hot butter—it will lower the dough temperature and retard the growth of yeast. If we’re not pushing the clock, we don’t mind. A slower growth of yeast creates a different nuance of flavors that we like. We usually stick the bottle of oil in a bowl of warm water until it’s viscous enough to pour.
Butter vs. Oil in a Bread Machine
Switching fat ingredients in the bread machine is a different story. There just isn’t much margin for error in a bread machine. When the timer goes off, the bread is going to bake—ready or not.
Either temperature or hydration (the amount of liquid) will affect the rise time. Yeast growth is very sensitive to temperature. Hot melted butter or cold oil will give very different results. Whether using melted butter or oil, the temperature should be between 80 and 100 degrees for most recipes.
All else being equal, a soft bread dough—one made softer with more moisture—will rise more quickly than a stiffer dough. A little bit more or less water will make quite a difference, enough of a difference to spell success or failure in your bread machine.
A Baker’s Note: Always measure water carefully and make sure that your measuring cup is accurate. We continue to be amazed at the number of measuring cups on the market that are substantially inaccurate. Test yours at different levels to make sure that it is accurate.
Margarine has a water content of about 15%–but differs significantly with different brands–and may affect the hydration of the dough.
We have heard reports from Iraq and Afghanistan of soldiers using squeeze bottles of liquid margarine with our bread machine mixes. They may be tinkering with the water amount just a bit but we haven’t heard of them doing so.
Muffins and Quick Breads
Butter or Shortening
You can make lighter muffins by creaming the butter or shortening with the sugar since you are entraining air into the mixture that will help the muffins rise during baking. Muffins made by this creaming method—with either butter or shortening–tend to be lighter.
Shortening tends to make a light, tender crumb. You can substitute part of the shortening with butter to retain some of the butter flavor.

Oil Instead of Butter

Muffins made with oil will keep longer. If you are using the muffin method of mixing, oil is convenient.
Which makes for the better muffin? That depends on the recipe—some recipes tend to work better with one than the other.
Don’t assume that the recipe developer made the best choice. The developer may have started with butter, made an acceptable product, and never tested further. If you are not perfectly happy with your recipe, try substituting. You can always substitute oil for butter and vice versa.
Cookies

You can’t easily substitute butter for oil or shortening in most cookie recipes. Most cookie recipes require creaming the sugar and butter or shortening together so using oil is not an option. We’ve substituted butter for shortening in recipes. Sometimes it works and sometimes it doesn’t. Sometimes it works in a 50–50 split.
In general, though, cookies made with shortening tend to be crisper, cookies made with butter tend to be softer and spread more, and cookies made with butter tend to brown easier.
Much of baking is trial and error. We hope this gives you the freedom to do a little experimenting and the guidelines for doing so. You might just make that favorite treat even better.
Related reading:
“Storing Fats and Oils” is a food storage bulletin that will tell you how to store your oils so that they will be fresh and healthy when you use them.
“A Cookie Troubleshooting Guide” will help you experiment with your cookies. If you would like the entire cookie guide, it is available for download—free—by clicking the above link.