I am making a gravy for mashed potatoes. Looking at recipes online, I have found that a few of them don't require any butter, while others use them to varying ratios (to broth/water)

What is the role of this ingredient in an excellent gravy for mashed potatoes?

I thought of two:

  1. Fat. Butter is rich in fat, and the increased fat in gravy helps it to coat and stick to the starchy molecules of the potatoes better, so they come together better in each bite.

  2. Thickening. The oil in butter and the broth used in most gravy come together as an emulsion of sorts, like the way mayonnaise is made. This helps to thicken the gravy.

  • 4
    Your question is unclear. Do you mean making a roux gravy, or adding butter at the end to a starch gravy, or something else? If these terms confuse you, you can just post an example of the recipes you mean. – rumtscho Oct 21 '17 at 10:59
  • Butter in general is for texture, moisture, and taste. With any dish there will be variations. – paparazzo Oct 21 '17 at 14:05
  • @rumtscho I meant a gravy for mashed potatoes, which usually involves butter, flour, beef or vegetable broth and ingredients for flavour, like onions and mushrooms. – user60513 Oct 21 '17 at 16:49
  • @user60513 this is an ingredient list, not a recipe. We cannot tell you anything about the role of the butter without knowing how it is used. You'd have to post a full recipe, including the steps. – rumtscho Oct 21 '17 at 17:48

The most common purpose of butter in gravy is for a roux, which is a thickener made from cooking flour in fat. Stock/drippings alone would be too runny, so it is thickened to make it more convenient to eat with the mashed potatoes. If the recipe doesn't call for a roux, it probably uses cornstarch as the thickener. Using cornstarch would be a slightly healthier option (no additional fat) and doesn't impart a flavor, while a roux can add a slightly nutty taste depending on how long its cooked.

  • Thank you. However, couldn't the flour be added immediately to the vegetable broth/water to thicken it into a gravy? Why is it necessary to create a roux first? – user60513 Oct 24 '17 at 9:48
  • 1
    Cooking the roux removes the raw flour taste, which you definitely don't want in your gravy. Plain flour will probably clump too. – Evan Nowak Oct 24 '17 at 12:06

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