Knowledge Base

Sugar

What is sugar

 

Sucrose

 

Sucrose is the most common type of sugar, it is naturally present in ripened fruits, plants, honey and maple tree sap.

Commercial production of white sugar (99.9% sucrose) involves purifying the natural sucrose from sugar cane or sugar beets. This is then sold in different size grains as granulated, caster or icing sugar.

 

The grain size is expressed in microns (one millionth of a meter) grains less than 45 microns aren’t easily felt in the mouth.

 

Lactose

 

A type of sugar found in most mammals’ milk. It is made up of glucose and galactose, two simple sugars used directly by the body for energy. The enzyme lactase splits lactose into these two parts to be used for energy. Lactose is the sugar found in all dairy products that have been produced from the milk of an animal.

 

Glucose

 

Glucose is the most common sugar in nature. You can find glucose in nearly all ripe fruit and it is what is referred to as ‘blood sugar’ high levels of which is dangerous for people with diabetes.

 

Fructose

 

A sugar found in most fruits, where it is often bonded to glucose (making sucrose). It is one of the three sugars that are absorbed into the blodd during digestion (glucose, fructose and lactose).

 

 

A brief history of sugar

 

Sugar cane is a tall reed like grass that was first cultivated eight thousand years ago in the south pacific. It then found it’s way to India, China and the middle east. These regions have used sugar for two or three thousand years.

Europeans wide use of sugar came a lot later with the colonisation of the West Indies by Spain. By the 1600’s it was widely available in Europe but still expensive. The slave trade was then introduced to increase production and the development of more efficient refining methods brought down the price in the 1800’s, making sugar accessible to the middle class.

 

In the 1700’s sugar beets started to be processed into sugar. This is less labour intensive and can be cultivated in milder climates, the anti slavery movement also fuelled the use of sugar beets as a method for producing sugar.

 

Sugar beets have been refined over centuries and now contain about 17% sucrose, which is slightly more than sugar cane. Sugar beets are now the predominant source of European sugar.

 

 

How is it made

 

Producing sugar involves two steps, milling and refining.

Milling involves taking raw sugar from beets or cane and refining is the process of turning this molasses covered raw sugar into pure white sugar or it’s less refined alternatives such as brown sugar.

 

The first step is to crush the fresh sugar cane and extract the juice with water. Calcium hydroxide and carbon dioxide are then added to the cloudy juice to trap impurities (fat, fibre and debris) which sink to the bottom and are drained off from the clear juice. Water is then evaporated to reduce it to a thick golden syrup. This is then divided into wide heated vacuum pans which concentrate it further. Once the syrup is concentrated enough, sugar crystals start to form. The crystallised mixture is then spun in a centrifuge to separate the crystals from the remaining liquid (molasses). This process is repeated a few times to get as much sugar separated as possible

 

The sugar comes out of this process as light brown raw sugar, which then can be further refined to white sugar.

 

To get pure white sugar the light brown sugar is then sent to a sugar refinery where it goes through a process of washing and centrifuging to remove the last of the impurities. It is also passed through a carbon filter to decolourise and further purify the sugar, just the same as filtering water. Some sugar can producers still use bone char from cattle for this purpose, so can be a problem when producing vegetarian or vegan products.

 

The sugar is then crystallised once more, dried and packed.

 

The syrup left behind is called refiners syrup, however it is usually sold as molasses (the name refiners syrup just differentiates this molasses from the molasses produced during the milling process).

 

 

Types of sugars

 

Caster sugar

 

Named after the small container used to serve sugar in Britain. This is the most common sugar used in baking. It is great for sponges since it dissolves quickly and allow the incorporation of smaller ait pockets in sponges and meringues

 

Granulated sugar

 

Usually used for syrups, sprinkling on fruit or the top of baked goods for a crunchy effect. Since the larger crystals are harder to dissolve it can cause grittiness, so it is not used as much in mixes.

 

Icing sugar

 

Also known as confectioners’ sugar, this is a fine powder made from refined white sugar. If needed, this can easily be made by placing caster or granulated sugar in a grinder/ blender and grinding to a fine powder.

 

Neige décor

 

Icing sugar made from corn starch. This is designed not to melt in humidity like regular icing sugar so is a favourite with pastry chefs for dusting products that are moist or hot.

 

Pearl sugar

 

Pearl sugar is white rounded granules that don’t dissolve easily. It is used to create a crunchy topping on products like cinnamon buns. It can also be called sugar nibs, sanding sugar or decorative sugar

 

Coarse sugar

 

Coarse sugar is a little bigger than granulated sugar. It has the same uses as pearl sugar, however they are sometimes polished with carnauba wax (wax from a type of Brazilian palm tree) to make them shiny and also stop them from dissolving.

These sugars are the purest of all sugars, making them perfect for syrups and confections, but also the most expensive.

 

Brown sugars

 

Soft and light brown sugars are found a lot in baking. Brown sugar usually refers to fine granulated sugar that has had a small amount of molasses added to it for better colour and flavour. The strength and amount of molasses used will determine the different grades of colour and how soft and sticky the sugar is.

 

This can be done by boiling the sugar with molasses and allowing to re crystallise or simply by “painting” where the two are blended together until the molasses is evenly blended through the sugar.

 

Muscovado sugar

 

Derived from the Spanish word meaning ‘unrefined’ it is sometimes called Barbados sugar. Muscovado is made by the same method as light and dark brown sugars, however the concentration of molasses is slightly higher. (6% for light and 18% for dark)

Used mostly for its colour and flavour.

 

Demerara

 

Demerara is a type of Turbinado sugar, with large light brown crystals. Made from cane sugar it retains only about 2% of the molasses content so is free flowing and not as sticky as other brown sugars. The name comes from the Demerara region in Guyana where it was first produced, however the majority today is produced in Mauritius.

 

Sucanat

 

The trademarked name for an organic, free flowing and unrefined brown sugar. It is made by concentrating sugar cane juice to a thick syrup (molasses) and then stirred as it cools and dries. It is referred to as whole cane sugar since nothing is added or removed

 

 

 

Jaggery

 

Often called Gur, this is an unrefined sugar from India. It is made by boiling and stiring sugar cane juice until it reduces to a thick crystallised syrup. It is then packed into moulds and left to harden. It is then grated to produce what is know as shakkar (Hindi for sugar)

 

Turbinado

 

Turbinado sugar is similar in taste and colour to light brown sugar but is dry and free flowing instead of sticky (also called washed raw or unrefined sugar, but these are misleading). Turbinado is semirefined, crude sugar is steamed first to clean it. It is then washed and centrifuged to remove the molasses from the surface before being crystallised and dried. These leaves a golden brown sugar that still contains about 2% molasses.

The name Turbinado refers to the use of a centrifuge (turbine) so many sugars fall into this category, such as Demerara and Florida crystals.

 

Glucose

 

This is the most common type of sugar in nature and is present is almost all fruit. It’s presence in grapes is essential for wine making, providing the sugar for fermentation, so can sometimes be called grape sugar. It is normally made from cornstarch. In nature, glucose is the product made by plants during photosynthesis.

Natural glucose can also be found in honey, molasses and invert sugar.

 

 

Invert sugar

 

A name for any syrup that has equal amounts of fructose and glucose. It is produced by adding acids to a sugar (sucrose) syrup, heating it and then concentrating it. The acid breaks down the sugar molecules which is called “inversion” This leaves equal parts of glucose and fructose with some residual water and acid. The acid helps with extending shelf life and keeping products soft and moist for longer, which is why it is used a lot in bakeries and pastry shops in place of sugar.

 

Isomalt

 

A crystalline powder that is made from chemically modifying sucrose. The big difference with isomalt is that it is a lot less hydroscopic than other sugars, which is why it is used a lot for sugar work and sculptures.

 

Molasses

 

The concentrated juice of sugar cane, it is used mostly for colouring and flavouring different sugars or for rich fruitcakes

 

Golden syrup

 

Golden syrup is cane sugar syrup that is a bi- product of the cane sugar refining process. It can also be made by boiling sugar cane and lightly concentrating the juice.

 

Treacle

 

Treacle is a name for concentrated sugar cane syrups, also know as molasses

 

Honey

 

Flower nectar, collected and processed by honey bees. It was the sweetener used throughout history up until sugars mass production started in the 1700’s. The main reason we still widely use honey is for it’s unique flavour. After it is removed from the hives it is separated from the waxy honeycomb. It is then heated to kill any yeasts and dissolve the crystals.

Sometimes called natural invert sugar because enzymes in the honeybee invert the sucrose in the nectar to fructose and glucose.

 

Maple syrup

 

Maple syrup is made by reducing the sap of the sugar maple tree . 80% of the worlds supply is produced in south-eastern Canada and north-eastern united states. Maple syrup is boiled in open vats, but because the sap contains only about 2-3% sugar 150 litres are needed just to make one litre, this is why real maple syrup is so expensive.

 

Agave syrup

 

Agave syrup is made from the sap of Agave plants which look a little like Aloe Vera. It is native to the hot, dry regions of the southern United States and Mexico.

To make the syrup, the core of the planted is heated up and the sap is pressed out. They are available in different shades, but this is just an indicator of how processed/ refined they are.

 

 

 

What does it do

 

Sweetening

Widely considered the only function of sugar, however it is more important in pastry goods than just providing sweetness.

 

Different sweeteners and sugars will all have their own degree of sweetness, for example, dextrose is used in savoury ice creams to provide the properties of sugar without the sweetness.

 

Tenderising

When sugar dissolves it interferes with gluten formation and other structures by attracting water away from the gluten eggs and starch that all need water to form.

Sugar also increases the temperature that starches gelatinize and proteins coagulate giving a more tender texture. However too much sugar will prevent any structures forming which means products won’t rise or rise and collapse as soon as it comes out of the oven.

Too low sugar content can be seen on a cake by large cracks in the surface where structure has formed too quickly and steam has forced it’s way out of the top. Leaving a split in the top or side.

 

Retaining moisture and helping shelf life

 

Sugar also helps with shelf life since it retains moisture and stops the product drying out and going stale.

 

Fructose is the most hydroscopic of the sugars. Products containing a significant amount (products made with invert sugar, honey or agave syrup) will provide the longest shelf life. This is why invert sugar is used in place of sugar for most truffle, mousse and Ganache recipes in chocolate and pastry shops .

 

 

Stabilizing egg foams

 

Sugar can also stabilize egg whites, if added properly. This means it is possible to whip them up into meringues that won’t collapse or split. Although yolks can’t hold as much air, this is the same with egg yolks, forming the base of many sponges and cakes.

 

Yeast fermentation

 

Sugar is vital in the fermentation of yeast (lactose is the only exception). The yeast digests the sugars, producing carbon dioxide which leavens dough, providing the air pockets needed for bread and cakes.

 

Adding flavour

 

Some Sweeteners provide flavour as well as sweetness, for example, honey, maple syrup and molasses

 

 

Reducing iciness and hardness in frozen products

 

Sugar lowers the freezing point of frozen desserts. The way it does this is to hold the water particles which hinders the forming of ice crystals.

 

 

Preventing microbial growth

 

When the sugar content in a product is low, it can feed microorganisms and cause them to grow, however at high concentrations sugar can preserve products for years. The best example would be jam. Just like salt, sugar prevents the microorganisms from being able to access the moisture in the product. This also means that sweeter doughs will take longer to prove.

 

Brix and Baume

 

Sugar syrups are sometimes described by their content of solids. The Brix and Baume scales give a measurement which is measured by an Saccharometer (or hydrometer). The measurements are taken by measuring the “specific gravity” of a syrup which relates to the density.

 

For example, a syrup with 80% sugar and 20% water would measure 80 degrees Brix (43 degrees Baume)

The Brix and Baume scales can be measured using the same technique and are much like degrees Fahrenheit and Celsius, just a different scale for the same data

 

The two measurements can be converted using the formula below

 

Baume = 0.55 x Brix

Brix = Baume / 0.55

 

This is useful when making products such as sorbets, since at different times of year the fruit juices will have different sugar contents and this needs to be corrected to get the same texture in the end result.

Refractometer

 

In the past most pastry chefs used Saccharometers and the Baume scale, however now most have switched to using Brix and a Refractometer. Refractometers look like small telescopes that use the amount of refracted light coming through the syrup to measure the density. They also require a smaller sample and are easier and faster to use.

 

Sugar substitutes

Fructose
Fructose is naturally occurring monosaccharide found in honey, fruits, and most root vegetables. The powder form is sourced from beetroot, fruits, sugar cane, and corn. While fructose is the sweetest tasting sugar, it has a lower impact on blood sugars than glucose or sucrose (table sugar).

Studies have shown that both fructose and glucose are absorbed directly into the bloodstream. However fructose on the other hand doesn’t impact insulin levels. This is one of the reasons why fructose is a recommended ingredient for those who are diabetics or are going through a strict diet. Though it is slightly different in taste, the substitution of table sugar with fructose is rarely noticed.

If you’re using fructose in baking, you’ll need about 1/3 less fructose than table sugar, and you won’t need to compensate for the reduced volume. This is because fructose attracts more water and increases the height of baked items. It also makes baked goods remain moister for longer. Other than baking and crystallisation, fructose can also be added to glazes and dairy products to increase their viscosity. It will add more creaminess to ice creams, sauces, or marinades.

 

Maltose
Maltose is a kind of sugar syrup produced by germinating malt. It is made through the production of germinating grain, usually barley. When the grain is collected, it is then soaked and allowed to sprout. This malted grain is then added to a slurry of water and starch and then cooked to create the maltose, a unique type of sugar.

Maltosea’s sweetness is about 70% less sweet than normal sugar, however, it has a high GI (glycemic index). It is unsuitable for diabetics. Maltose has a certain toasty, nutty, caramelised flavour which means that it is not so much used as a sugar in cooking but as a flavouring. Ice cream and chocolate flavour well with maltose. This also works very well in bread and beer, as the sugar feeds the yeast without making bread too sweet. This will also extend the shelf life of these products. Maltose has a unique tolerance to heat and cold, thus meaning that it is works very well in frozen desserts and hard candies.

 

Sorbitol
Sorbitol is a sugar alcohol naturally extracted from fruit. In high production, sorbitol is extracted from corn syrup. Most common fruits with high sorbitol levels include prunes, apples, pears and bananas. Sorbitol works very well when combined with other ingredients such as sugars, gelling agents, vegetable fats and proteins. It has a very low calorie content, lower than isomalt, which means that it can be used as a substitute within sweets, cakes, icings and fillings.

Sorbitol is the chemical in fruit that in excess can have a laxative effect, therefore is imperative that it is not overused.

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