Before we get into whether butter is better before or after toasting let’s quickly go over toasting methods.
Firstly, we don’t recommend putting butter in a standard toaster like the one pictured above. You are asking for a mess if you do this.
The butter will melt and slide down the vertically positioned toast. You will have the nightmare scenario of melted butter inside your toaster, which may ruin your toaster or potentially cause a fire.
Given the enclosed construction of a standard toaster, you should only use it for solid food items designed to go in a toaster such as plain toast, English muffins, waffles, and bagels without the addition of butter, cream cheese, etc.
You can butter your bread prior to toasting it if you have something like a toaster oven or griddle which allows the bread to lay flat. The butter will gradual melt on the bread as it toasts so be mindful about how much you use.
The use of too much butter can lead to it flowing off the bread only to burn on the heating element and other hot components in a toaster oven. If you like to butter your toast heavy, you may wish to add an oven tray under the grates that hold the toast to catch any butter that drips.
Butter Bread Before Or After Toasting?
We suggest buttering your bread before toasting when it is practical.
The taste of melted butter on toast is superior to cold or room temperature butter being spread on after toasting. The heated butter works it way into the bread’s interior while being toasted which produces a more balanced buttery flavor with each bite.
Additionally, the taste of the butter improves with the heating process. As America’s Test Kitchen explains, heating butter evaporates some of the water and the “sugars and amino acids in the butter react to create new flavor compounds”. These compounds create highly desirable nutty and savory flavors with a bit of sweetness.
One of the best times to butter bread before toasting is when you use stick butter straight from the refrigerator. Cold stick butter spreads terribly making it challenging not to rip apart the bread when buttering it.
Add a tablespoon or so of stick butter to the center of a piece of toast and place it in the toaster over. The butter will melt over the toast by the time the toast is toasted assuming you aren’t toasting lightly. The melted butter may need to be spread over the areas of bread that are unbuttered.