So, you’ve started a new cake, you’re happily cracking eggs and whisking them up ready to go into your mixture and…. Well, and what? What is the purpose of eggs in baking?
I’m sure you’re thinking ‘for fluffiness’, ‘for colour’, ‘to use up all the eggs in my house that the kids promised they would eat and have now totally gone off of them…’ (maybe that’s an issue for another time!).
There’s so much more to what eggs do in a cake though! Here we’ve got an egg-cellent comprehensive guide to the purpose of eggs in baking, including their fascinating history, as well as useful tips on things like how the number of eggs affects a cake and why having an eggs-act number is essential!
Don’t forget, there are plenty more articles like this one in our magazines, so get your copy today to get your mind whirring (along with your whisk!).
What do eggs do in a cake?
The history of eggs in baking
Humans have been eating eggs almost as long as they’ve been wondering which came first, the chicken or the egg? Whilst early humans wouldn't have realised it, but eggs are full of iron, vitamins, minerals and carotenoids (which makes the yolk orange and has been found to improve the accuracy of eyesight and protect the eyes from damage). The humble egg is thus a powerhouse of disease-fighting nutrient and was hugely significant in the early diet of humankind.
It’s very difficult to pinpoint precisely when eggs began to be used in baking, although it can be narrowed down to around the time that fowl, especially chickens, were becoming domesticated, increasing the availability of eggs across all social groups. This era of domestication is thought to have begun in China in around 6,000BC.
Culinary historians have confirmed the evidence of the use of eggs in breads and cakes by people in Ancient Egypt and Ancient Rome. This practice began as people discovered that, at that time, the purpose of eggs in baking was as a thickening agent. Whilst we’re unsure precisely as to why or how this discovery was made, it's presumed that it was through trial and error or simple accident – many foods and cooking methods, such as leavened bread, roasted meats and yoghurts, were ‘invented’ in this way.
Is the quality of an egg important in baking?
In short, YES! We always recommend using organic eggs. There are so many different labels on the market though – what do they all mean?
- Organic: Eggs labelled organic must be laid by completely free-range hens who are living a completely natural life, free of additional hormones and routine antibiotics. Organic laid-eggs are therefore produced by hens in small flocks, with better access to the outdoors (at least 10 metres squared) and more space inside their houses. Beak trimming, a process in the UK that involves using an infra-red beam to remove part of a hen’s beak to reduce the risk of injuries from feather picking, is banned.
- Free-range: Hens that produce free-range eggs have unlimited daytime access to outdoor runs with vegetation and at least 4 metres squared space per hen. While free-range hen barns are required to have bedding and perches, internal space requirements are no more than 9 hens per square metre. There is no limit on flock size, beak trimming is commonly practiced and antibiotics routinely given.
- Caged: It says it all in the name. While the EU banned traditional ‘battery’ caged hens in 2012, modified versions of these (such as ‘enriched’ and ‘furnished’) cages remain legal and are considered by many animal welfare experts as being not much better. A cage is still a cage after all. These hens have no access to the outdoors and very limited movement, often unable to fully stretch their wings. Beak trimming is routine, as are extra hormones for exaggerated growth and routine antibiotics.
We’re very passionate about animal welfare, especially that of chickens, so please, always buy organic for your bakes!
What is the purpose of eggs in baking?
Perfect for sweet and savoury meals, eggs can be scrambled, boiled, poached, pickled, devilled, baked, even covered in chocolate (well, not quite – we’re thinking of Cadbury’s Crème Eggs, but you get the picture!).
When it comes to baking, it's essential to understand the make-up and structure of an eggs if you want to achieve the perfect bake every time. The purpose of eggs in baking develops from a delectable full-English breakfast staple to vital ingredient for providing any of your bakes:
- Flavour: Use eggs to add a real richness to the flavour of a cake. Perfect if you’re looking to keep your bakes and flavourings as natural as possible!
- Structure: Eggs are a significant structure provider in baking, giving a cake firmness, lightness and stability.
- Aeration: Eggs can be whisked up or beaten into a cake mixture to incorporate air into the mix, helping you achieve that perfect rise.
- Colour: You know you’ve done a good job when your sponge comes out of the oven a beautiful golden colour. This is majorly influenced by the eggs you've used.
- Moisture: As eggs are 75% liquid (read on to find out more about the structure of an egg), they can be a key ingredient to moistening a cake.
- Texture: Not so much the egg white, but egg yolks are a great source of fat, which contributes to creating a really tender texture.
The role of egg yolks
If a recipe asks for just yolks, that’s generally because it wants to capitalise on the fat content and emulsifying abilities of the yolk. The fat in a yolk gives a cake an extra-rich flavour, as well as a smooth and velvety texture. The binding abilities of an egg yolk are not to be overlooked too, as it has a unique ability to bind liquids and fats together, which creates an emulsion that prevents them from separating. This ensures an even distribution of liquid and fats in your cake mixture.
Using only yolks does mean keeping a careful eye on temperature though! The proteins contained in an egg yolk unfold and gel together as it is heated, ideally resulting in a gentle thickening over a low heat. Whack up the temperature and you’ll find yourself with a sad bowl full of grainy and curdled eggs. No thanks!
The role of egg whites
You'll generally find that a recipe asking for only egg whites wants you to whip them. With a good whip, egg whites will expand and become incredibly fluffy as they are filled with millions of tiny air bubbles. The resulting foam-like texture can be folded into a cake, souffle or meringue mix to provide extra rise. This was the original way of getting cakes to rise, long before the days of baking powder!
As with the yolks, working with whites can be a delicate task. You may have heard the term ‘over-whipped’ thrown around a lot on shows such as The Great British Bake Off and Masterchef… but what does it mean? If you overwhip your eggs, they will become clumpy, grainy and won’t fold nicely into your mixture. This can also contribute to the final baked cake being dry.
What's in an egg?
Of course, we all know when you crack open an egg, there is the white and a yolk (sometimes two – not all eggs are created equal!). The white is packed full of proteins and water, whereas the yolk is all about the nutrients, vitamins and fats. If you look closely, there's also a thin white strand inside an egg shell, called the ‘chalazae’. This is key in maintaining the structure of an egg, anchoring the yolk to the white and the inside of the shell, keeping the yolk centrally suspended.
Whilst most recipes will call for ‘whites of 3 eggs’ or ‘2 egg yolks.’ However, some may specify eggs by weight instead, so here’s a handy table as to the proportions of an egg:
While this is just a rough guide, it's applicable to many other types of eggs and should be a handy conversion chart for other egg varieties.
How does the number of eggs affect a cake?
If you add too many eggs to a cake, you'll get a much thinner consistency of cake batter and, while it will be a stunning golden colour, you'll end up with a cake tasting and textured more like a baked custard.
If you add too few (or none at all!) without a suitable substitute (that’s for another post!), you will find your cake tastes very strongly of flour and possibly becomes excessively sweet, as there is no binding agent to counteract the raw flour or sweet elements.
Interestingly, adding too many eggs or not enough eggs will leave you with a very short and dense structured cake either way. With no eggs, you’re looking at a crumbly consistency, whereas with too many eggs, you’ve got yourself a rubbery cake!
So, always follow your recipes! If your cake mixture is looking a little dry after adding your eggs, it’s best to add a splash of milk instead of a whole new egg.
We bet you thought this was going to be an egg-stremely short and sweet article on the purpose of eggs in baking? Not from Food Heaven! When we promise a comprehensive guide, we deliver the goods!
If you found this article on what do eggs do in a cake eggs-tra useful, we’ve got plenty more articles like it! If you’re concerned about baking times, perhaps you have a quirky oven that chooses its temperature depending on the current phase of the moon, we’ve got a fantastic guide on how to tell if the cake is done!