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  • Writer's pictureJulia

The Science of Baking - The Sweet Stuff! (free recipe inside 😊 🍬)

Updated: Jul 14, 2020

Following on from this post on the various types of flour used in baking, today we are looking at the sweet stuff - sugar!

I know this is another long read so if you just want to get to the recipe at the end then scroll down to the bottom for my really easy white chocolate fudge recipe.

Sweeteners are one of the most important ingredients used in bakery foods. While there are many different sweeteners available, sugar is perhaps the most versatile. Sugar is a natural substance occurring in two plants: sugar cane and sugar beet. A large variety of sugars can be produced by extracting and purifying sugar from these plants, which may differ in colour, flavour, sweetness, and crystal size. For example, the molasses in brown sugar gives it a different flavour and appearance compared to granulated white sugar. Sugar can also be used in both crystalline and liquid forms. All of these characteristics contribute to the variety of functions performed by sugar in foods. Sugar not only makes foods taste sweet but it also has many other functions. It is a vital component in the chemical process that converts the recipe from batter to baked goods. Without it, not only would they not be sweet but they wouldn't bake at all like we know them.


Many recipes call for creaming the butter and sugar together. By beating the butter until it is fluffy you are incorporating air into it and when you add the sugar the little granules are cutting tiny holes of air into the mixture, even whilst the butter is making them dissolve into the batter. Later on, the air will come together with your raising agent and expand, making your baked goods rise.


When you boil sugar and water it turns a lovely rich brown colour and thickens. This is called caramelization. In the baking process something similar happens to your baked goods because of the addition of sugar. When something is baked, a frequent marker of doneness is looking for a golden-brown colour. This colour is thanks to the sugar, and something called the Maillard reaction. When heated, the sugar reacts with proteins from other ingredients and this is what causes the browning. If your cakes brown too quickly, it could be that you have added too much sugar.

Sugar attracts water Sugar is hygroscopic. This means that it’s able to attract and hold on to water molecules, “suspending” them evenly throughout a batter during the baking process. Sugar acts as an important tenderizing agent in foods such as baked products. During the mixing process, sugar competes with other ingredients for water. The result is a moister cake. Different varieties and amounts of sugar will have different results. The ability to attract moisture also has a stabilizing effect on baked goods, so that they may maintain texture and flavour, usually for least a few days. These hygroscopic properties are not limited to granulated sugar. They are present in other sugars, such as brown sugar, molasses and honey, too (although the resulting baked goods will tend to be chewier and more dense with these).

Food Preservation and Fermentation

Sugar plays an important role in extending the shelf life of bakery products. Sugar binds to water molecules, slowing moisture loss and preventing staleness in baked goods. In addition, the glucose/ fructose mixture in invert sugar present in jams helps to inhibit microbial growth and spoilage. Fermentation, an extremely important process in the baking industry, is fuelled by sugars. Sugars are used to activate yeast for fermentation. The type and amount of sugar added can increase the dough yield and softness of bread by altering the rate of fermentation. When a hard crust bread is desired, sugars are either omitted or used in lower quantities. In this case, the yeast is activated by sugars formed when starch is broken down by enzymes present in the flour. Sugars remaining after fermentation contribute to the overall flavour, colour and texture of the final product.

Sugar is an Antioxidant Sugar can act as an antioxidant in some foods. It is able to slow down oxidation reactions, which cause food to deteriorate. Sugar plays a number of different roles in baking that go beyond the perception of sweetness and can be used in nearly all baking applications, including yeast-based products, chemically leavened products, icings and fillings.

How Much Sugar? If you are tempted to tinker with the amount of sugar in your recipe because you think more will make the result sweeter, or you want to reduce the amount of sugar for health reasons, this can have ruinous effects on your baked goods. Sugar has a chemical reaction in the baking process and it can cause some problems.

Too Little Sugar Baked goods won’t brown properly (if a cake doesn’t turn golden, for instance, it’s hard to tell when it’s done), and of course, inferior flavour and texture.

Too Much Sugar Cakes brown too rapidly on the top but are not completely baked on the inside. The flavour might be acceptable, although rather sweet, but you will again have inferior texture.

Does it Matter What Kind of Sugar You Use?

It depends on the recipe. Generally, you should assume that a particular type of sugar was chosen for a specific reason. Texture isn’t the only issue. By swapping sweeteners in a recipe, you may alter the chemistry of your baked goods, and you may seriously alter the outcome. For instance, if you swap molasses for sugar in a cookie recipe, you won’t be able to engage in the creaming process, which aerates the batter. The resulting cookie will be a lot heavier than you may have intended.

When it comes to substituting, the general rule is that you can swap, but don’t go out of the ballpark. Pair like with like. For instance, swapping dark brown sugar if the recipe intended light brown sugar won’t mess up the baking, but it may alter the final flavour. Using honey instead of maple syrup will work, with the only major change being the flavour alteration. But you can’t stray too far: swapping molasses for granulated sugar in a recipe, for instance, will seriously alter the finished product.

Different Types of Sugar

White caster and granulated sugars are highly refined and high quality sugars which are free flowing. Granulated sugar has larger sugar crystals than caster sugar and is perhaps the most versatile. It is used in the manufacture of fondant, boiled sweets and boiled sugar work, jams and marmalades. It also acts as a sweetening agent in beers, ciders and wines. Caster sugar is useful in confectionery, creaming, mixtures, pastes, whisking and batters.

Icing sugar has a superfine texture produced by grinding cubes of granulated sugar until various grades of fine or semi-fine sugar are obtained. It is generally very white in colour and used for icing cakes. A small quantity of calcium phosphate or other anti-caking agent is added to assist its free flowing, prevent lumps forming and absorb any moisture. Icing sugar is used for the production of royal and other icings, buttercreams, biscuits and confectionery fondants and pastes.

Cube sugar is mainly used for boiled sweets, jam making, stock syrups, confits and sauces. It's the most suitable sugar for boiling as it can be saturated with the minimum amount of water. In medieval times, large lumps of sugar were given names like sugar stone, sugar loaf and sugar rock. In later years, loaves of sugar were made by pouring the syrup into conical shaped iron frames. These had a hole in the tip for the syrup to drain away. When the mould was removed the cone shaped block of sugar was placed in a warm room to dry. Lumps of sugar would then be hacked off this cone and pounded with a pestle and mortar until the required consistency was achieved.

Sugar nibs are pieces of loaf sugar screened to a precise particle size range. They have a soft, crunchy texture and are mainly used for sprinkling on cakes, sweet buns and chocolate confectionery.

Brown sugars or unrefined sugar are moist to the touch and adhere in lumps due to the quantity of syrup present, known as cane molasses. In addition to sweetness, brown sugars have the aroma, rich flavour and colour that is always associated with raw cane sugar. Brown sugars are used for the production of rich fruit cakes, puddings and confectionery such as toffee and fudge.

Foot sugar is crude, unrefined raw sugar which is very dark brown and contains a considerable amount of molasses and uncrystallised sugar. The name originates from the time when Barbados sugar was imported in large casks known as hogsheads. The molasses which had not been completely cleared from the crude sugar, settled at the bottom of the hogshead and was given the name foot sugar. It is used for dark cakes such as wedding and Christmas cakes and puddings but you don't see it much these days.

Barbados sugar, more commonly known as muscovado sugar is partly purified sugar imported from Barbados. It has a rich flavour and can be blended with other sugars. It is used in the production of sauces, boiled sweets, rich fruit cakes and puddings.

Demerara is a partly purified crystalline sugar which is yellowish brown in colour. It takes its name from a historical region in the Guianas on the north coast of South America which is now part of the country of Guyana. It was a Dutch colony until 1815 and a county of British Guiana from 1838 to 1966, located on the Demerara River. It imparts a syrupy flavour and has a number of uses including some boiled sweets, toffees and fudge.

Molasses is the residual syrup that is left when the sugar has been through the crystallisation process. Molasses from cane sugar is edible and widely used for fermenting in the manufacture of rum or other spirits. Molasses from sugar beet has a strong bitter taste and is mainly used in the production of cattle food as it contains calcium and iron. Mixed molasses are also used in the manufacture of yeast.

Black treacle is a by-product of the refining process and is the liquid portion which drains from the crystals in the crystallisation vats. It is used to provide flavour and colour and is useful in the production of Christmas produce, used either alone or combined with milk or water for gingerbread, gingernuts and parkin.

Golden syrup has a unique flavour and is resistant to crystallisation. Classified as a pure sugar product, It is made by partially inverting syrup taken from the refining process and has many applications. It's very soluble in water and when highly concentrated solutions are used in jam and preserve making it is an effective preservative. Invert sugar in baked products helps with moisture retention and can improve keeping properties.

Honey is a golden sugary fluid made by bees from nectar collected from flowers and has many uses. The earliest confectioners made good use of honey and even today certain traditional sweets are based on honey. Honey contains 75% invert sugar and is hygroscopic. It's main use in confectionery is to add flavour.

Liquid glucose, although technically not really a sugar product, it is an important basic ingredient in confectionery as it doesn't crystallise and when mixed with a sugar solution tends to prevent the sugar from crystallising. It is hygroscopic and products containing glucose will remain moist. It's made from starchy foods such as maize, potatoes and wheat.

Other Sweeteners

Many sugar substitutes are not generally appropriate for baking. Firstly, many are far sweeter than natural sugar, and the flavour just doesn’t work. Secondly, the chemical makeup of these sugar substitutes is different, so the chemical reactions during the baking process won’t necessarily be the same. If using a sugar substitute, make sure it is labelled as being suitable for baking.

I know this has been another long read so if you have managed to get to the end again here's a little treat for you. This time, I am sharing a really easy white chocolate fudge recipe. I'm all for making life a little easier and, seriously, it's probably the easiest fudge you will ever make. Click here to grab the recipe. I added some chopped hazelnuts to mine for extra crunch.

White chocolate fudge

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