Baking with olive oil
Anyone reading my blog may notice that I use olive oil in most of my baking. However, some people find the taste of olive oil a little too strong in cakes and biscuits. The intensity of the olive oil flavour varies and it is worthwhile choosing a mellower flavoured oil for baking. A more neutral flavoured oil such as sunflower oil could also be substituted, but the health benefits are not the same as those of olive oil.
I use olive oil for three reasons:
1) To keep my baking dairy-free. Dairy used to exacerbate my sons eczema although I think he may be growing out of that problem.
2) To maximise the quantity of ‘good fats’ in my family’s diet.
3) and finally to keep the finished product moist. According to Shirley O. Corriher in her fantastic book Bakewise, oil greases flour proteins better than butter and prevents the formation of gluten sheets that are desirable in bread but make cakes and pastries tough and dry.
Let me explain the differences between the main types of fats and oils typically used in baking. Butter and vegetable oils (including olive oil) all contain triglycerides. Triglycerides are composed of a glycerol backbone with three fatty acids attached. The fatty acids are what we are most interested in when discussing the health properties of fats and oils. There are three main types based on their chemical structures. They are saturated, mono-unsaturated and polyunsaturated. The fatty acids found within a particular source of dietary fat are usually a mixture of the three chemical types, but one of them will predominate and that is what the health claims for that fat/oil are based on.
Olive oil, which is considered a fruit oil, is made up of mostly oleic acid which is a monounsaturated fatty acid, but also contains some linoleic (polyunsaturated), palmitic and stearic acid (both saturated). Mono-unsaturated fatty acids have been shown to be heart protective. Canola oil is another cooking oil that contains a high proportion of mono-unsaturated fatty acids, however, the production process is different as discussed a little further below.
Butter, coconut oil and palm oil are made up of predominantly saturated fatty acids. To the best of our knowledge at this point in time saturated fatty acids, such as those that predominate in butter have been associated with cholesterol increases and heart disease. However, this is a rapidly evolving and controversial area of research and is much more complicated than simply labeling all saturated fatty acids as detrimental to health. Even within the saturated fatty acids different fatty acids have been shown to have varying effects on health. Particularly on the levels of different types of cholesterol in the blood. See my article on coconut oil for more information about the health effects of coconut oil and different types of cholesterol.
Other cooking oils, usually derived from seeds, contain mostly polyunsaturated fatty acids. Polyunsaturated fats can be classified into omega-3 and omega-6. The omega-3s are more heart protective, but the only vegetable oil typically used in cooking that contains a significant amount is canola oil (other oils high in omega-3s, such as flaxseed and walnut oil, are good on salads or in smoothies) . Other sources of Omegas-3s is oily fish. Most vegetable oils used in cooking are high in Omega-6 fatty acids. Omega-6s are more associated with inflammation. Some evidence shows that diets high in omega-6 and low in omega-3 may increase the risk of cardiovascular disease.
Olive oil is pressed from ripe olives and the juices are collected to constitute the olive oil. You will see the term ‘cold-pressed’ on your olive oil tin or bottle. Extra virgin olive oil is collected from the first pressing of the olives and has the strongest flavour. Virgin olive oil is collected from the second pressing. Oil collected from subsequent pressings are used to make olive oils even lighter in flavour.
Other oils such as canola, sunflower and grapeseed oil are manufactured at high temperatures often involving toxic chemicals, like hexane. The oils may then be bleached, deodorized and further refined at high temperatures.
Coconut oil is also usually cold pressed and butter is made by heating and churning pasteurized cream.
So while the health effects of many oils and fats are somewhat controversial and unclear the benefits of olive oil have never been in question. So that is why I will continue to stick to olive oil for cooking and baking. It should be kept in mind, however that heating olive oil above smoke point temp will result in some oxidation and reduction in quality. Smoke point varies with quality but generally it is okay up to around 200°C.
For recipes which call for any other liquid oil (such as sunflower or canola) olive oil can be substituted in the same volume. If a recipe calls for butter and you want to substitute with olive oil the conversion is usually ¾ of the butter amount. For example if a recipe calls for a cup of butter I would use ¾ of a cup of olive oil. Sometimes this direct conversion works great and other times I find I need to make up the missing ¼ with a liquid (usually a type of milk). You may need to play around with your recipe to optimize it.