Brown butter is butter that has been heated until the water content has boiled off and the remaining liquid has turned brown. It is often called for in cooking and baking, for example in recipes for financiers.

Discussions of the process typically explain the brown color as browning of the milk solids in the butter due to the Maillard reaction. However, even when these milk solids are removed, as is done in most recipes by filtering or careful pouring, the brown color remains.

I believe I understand how the flavor components of the brown butter survive filtering - the volatile products of the Maillard reactions remain dissolved in the liquid fat - but is there a similar explanation for the brown color? Or is it down to the coarseness of the filters allowing small suspended particles through with the liquid?

Any details on the particular compounds responsible for the color, or the chemical processes involved in creating them, would be much appreciated.


2 Answers 2


The Maillard reaction is also called the non-enzymatic browning reaction. The reaction occurs when there are reducing sugars and amino acids present. The reaction is controlled by solvent choice, time and temperature considerations.

When browning butter, certainly, the Maillard reaction is occurring. There may also be other reactions happening such as Strecker degradation and caramelization.

As noted, browned butter is made by essentially heating butter until the water boils off at 100C and then the temperature ramps upward. So, what is causing the browning once the browned particulates are strained out? Some are chemicals that are formed from the reaction.

The color comes about due to production of melanoidins. As the Maillard reaction produces a range of chemical compounds, some of the components may have a lot of color on their own, such as furfural and its derivatives.

Professor Chi Tang Ho at Rutgers University has done extension work on Maillard reactions in model systems. Heath & Reineccius in their book Flavor Chemistry and Technology write about the Maillard reaction in more general terms that includes more on color production as part of the process.


Your first link (Brown Butter) states that heating allows for separation of the butterfat from the milk solids, which sink to the bottome of the pan and turn brown.

According to this Wikipedia page about a popular drink in rural Russia called baked milk:

In rural areas baked milk has been produced by leaving a jug of boiled milk in an oven for a day or for a night until it is coated with a brown crust. Prolonged exposure to heat causes reactions between the milk's amino acids and sugars, resulting in the formation of melanoidin compounds that give it a creamy color and caramel flavor.

While the color of baked milk is described as "creamy", the picture below (from the same Wikipedia page) shows that it has a distinct brown color. I suspect the reactions described above that give baked milk it's color also give the milk solids in brown butter it's distinctive brown color.

enter image description here


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