Coconut oil vs vegetable oil
Called an oil and solid at room temperature, which makes it the one “oil” that can do a block fat's job — and the one that will not pour when the recipe expects it to.
The short answer
The name is the problem. Coconut oil is highly saturated and solid at ordinary room temperature, so in the ways that matter to a baker it is a block fat that happens to be sold in a jar — it can be creamed, it can shorten pastry, and it sets firm in an icing or a chocolate coating. Vegetable oil is liquid at every temperature a kitchen reaches and can do none of those things; it coats flour thoroughly and makes a very tender, moist crumb that stays moist in the fridge. Substituting one for the other works only where the recipe wanted a liquid fat, and coconut oil poured in melted is then equivalent. Where creaming or rubbing-in is involved, they are not substitutes at all.
Where they differ
| Dimension | First | Second |
|---|---|---|
| State at room temperature | Solid, or soft-solid in a warm room. | Liquid, always. |
| Can it be creamed | Yes, if it is at the right temperature. | No. |
| Pastry | Works — it can be rubbed in and it makes layers. | Cannot. There is nothing to stay in pieces. |
| Crumb produced | Closer to a butter cake; firms in the fridge. | Very tender and moist, and stays soft when cold. |
| Flavour | Coconut, unless refined — and refined is widely sold. | Neutral. |
| Behaviour when cold | Sets hard, which is why it is used in raw slices and coatings. | Stays soft. |
The temperature trap when substituting
The instruction “use melted coconut oil” hides a problem that catches people repeatedly: melted coconut oil re-solidifies the moment it meets anything cold.
Poured into a batter containing fridge-cold eggs or milk, it seizes into small hard flecks and the batter looks curdled. The bake is usually salvageable and the texture is not quite right, because the fat is no longer evenly dispersed.
The fix is to bring the other wet ingredients to room temperature first — the same rule that applies to any creamed batter, arriving for a different reason. Vegetable oil never has this problem, which is part of why oil cakes are so reliable.
Related
Compares
The one oil that is a block fat in a jar, and where treating it as a liquid stops working.
The one oil that is a block fat in a jar, and where treating it as a liquid stops working.