Oil vs. butter in baking: what does science say about fats?

Have you ever wondered what the difference is when using butter instead of oil in baking? Wonder no more!

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We all know that oil and fats play an important role in baking, however not many of us will have really thought about why cake fats are so essential to a cake mix. Using butter instead of oil can actually make a vast difference in the structure, texture and taste of your cake. So, we decided to pit the two against each other: butter vs oil in cake baking. Who will win? There’s only one way to find out…

What are the purposes of cake fats?

Cake mix uncooked

There are several key reasons as to why fats in cake are so important:

Flavour

Fat plays an essential role in adding flavour, moistness and richness to any baked food. Generally, the more and better quality fats in a bake, the better the taste. If you’re looking for luxury, high-quality fats are what you’ll want.

Texture

We’re delving into baking science again here. Fats react with gluten by shortening the gluten strands. This means that foods like cinnamon rolls are more tender than baguettes, as the fat content is far higher, therefore the texture is far more tender. When fat meets flour, it coats it and becomes a kind of barrier between the proteins and water, which slows down the gluten development.

Rise

As we’ve discussed before in our articles on sifting flour, and what do eggs do in a cake and how does baking powder work, each ingredient that makes up a basic cake batter has a hugely important role to play in leavening the bake while cooking. Cake fats are no different and this is why it's essential to always cream solid fats with your sugar, as it supports the ‘web’ of air that has been beaten in, lifting and leavening the whole bake.

What does oil do in baking?

olive oil image

This may seem like a very generic question, as there are literally hundreds of different oils you can buy out there, from regular olive oil to avocado, coconut and even Scottish seaweed oil! However, it's important to note that all oils actually function in the same way in baking, as they are all 100% fat. It’s better to avoid olive oil when baking though and instead go for something with a more neutral flavour, such as vegetable oil. Olive oil has its own quite strong flavour and can completely throw out the taste profile of your bake.

The main role of oil in baking is to add a richness and tenderness, with tenderness being greater than in bakes that use butter. This is due to how liquid cake fats, such as oil, don't solidify when they cool. This is however to the detriment of the rise in the bake, as with it not solidifying when cooled, liquid fats cannot support the ‘web’ of air we discussed earlier.

What does butter do in baking?

Butter image

A solid fat, butter adds a wonderful flavour to baked goods that isn’t as intense as something like olive oil. The presence of water in butter is also great for helping your bakes rise, as it evaporates in the hot oven but, as it is trapped within the dough, the steam helps it to rise.

Any solid fat, such as butter, comes under the baking name of ‘shortening’ (now you know why vegetable shortening is called just that!). This is to do with how the fats shorten gluten strands, slowing down the process of gluten formation to create a more tender end product.

Top tip! It’s important to note here that margarine is not an ideal substitute for butter, if you’re looking for the same result, as it contains significantly less fat. Whilst most butters contain around 80%-85% fat, some margarines can contain as little as 35% fat. Unless directly instructed, it's always better to use butter rather than margarine as your solid fat in baking.

Oil vs butter in baking

Muffin batter

As often happens in these articles, it’s really hard to choose a winner! It’s not about winning and losing in cake decorating and baking anyway, it’s about finding what is best for you and your personal baking style and methods.

While for many of us, butter will always be the go-to cake fat, oil certainly has its charms and can often be a top-quality substitute. If you’re looking for a really moist cake, it’s definitely worth giving oil a shot. Indeed, we’ve found that replacing butter with oil in coarser cakes such as carrot cake had a really positive effect on the taste of the final product.

If you’re looking for a fine texture however, butter really is the way to go. The smaller crumb created from the solid fats means a much finer texture than is created with oil, which will generally produce a coarser and more open crumb in your final product.


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