Butter is more expensive than oil, harder to work with at scale, and less shelf-stable. We use it in every cookie anyway, because there isn't a substitute for what it does to flavor.
What butter does that oil can't
Butter isn't just fat — it also contains milk proteins and milk sugars, and that combination is what drives the Maillard reaction, the chemical process responsible for browning and, more importantly, for flavor development in baking. Vegetable oil is essentially neutral: it has no proteins or sugars to drive that reaction, so it can help distribute heat evenly, but it isn't contributing flavor the way butter is. Brown butter — the deep, nutty flavor you get from browning butter's milk solids — is a direct example of the Maillard reaction at work, and it's simply not something oil can produce.
That's the real, unglamorous reason our cookies taste like something a person baked rather than something a factory extruded: the fat itself is doing flavor work, not just moisture work.
The harder tradeoff
Butter is less forgiving than oil. It behaves differently depending on temperature, it's pricier, and it doesn't have the shelf stability of a seed oil — all of which are real reasons so much of the packaged food industry defaults to oil instead. We didn't choose butter because it was the easier path. We chose it because a cookie made with real butter simply tastes like a better cookie, and taste was the non-negotiable brief from day one.
Quick Answers
Why does butter matter so much in baking, chemically speaking?
Butter contains milk proteins and sugars that drive the Maillard reaction — the process responsible for browning and flavor development. Oil doesn't have those components, so it can't do the same flavor work.
Is butter harder to bake with than oil?
Yes — it's less shelf-stable, pricier, and more sensitive to temperature, which is part of why so much of the packaged snack industry defaults to seed or vegetable oil instead.
Does Fields Good use any oil at all?
No seed or vegetable oils in any cookie. Fat comes from real butter, cocoa butter, and, in the Protein Cookie, real peanut butter.
