Some useful basic information about sugar.
Sugar is one of the most popular basic ingredients for making mixed drinks, such as lemonades, the old fashioned, and everything in between. There is a huge number of ways you can use sugar at the bar; if you've never made a “home-made” syrup in your life, that’s probably because you've been consciously avoiding it. But do bartenders have in-depth knowledge about this ingredient? How many of them know how much sugar they can possibly dissolve in water, what BRIX stands for, and what the term “osmosis” has to do with syrups? In this article, I will try to shed some light on these questions, although we'll just be barely touching the tip of the iceberg anyway since this is a wide-ranging topic.
First things first: let's define what sugar actually is. According to Collier's Encyclopedia, “in chemical terms, sugar is any substance belonging to the vast group of water-soluble carbohydrates, it normally has low molecular weight and a more or less pronounced sweet taste. The term “sugar” mostly refers to monosaccharides (simple sugars) and disaccharides, the molecule of which consists of two residues of monosaccharides[…]. However, in everyday language, it is common to refer to the usual food sweetener — sucrose — as just sugar".
This is what a sucrose molecule looks like:
Fructose, also known as fruit sugar, laevulose, or arabino-hexulose. The main fructose sources are honey, agave syrup, various kinds of fruit, berries, and root crops. What makes fructose interesting is that its sweetness changes depending on the temperature. The fructose molecule has several possible forms and depending on the temperature, the sweetness is determined by a certain molecule form. At 5 ºC, the sweetness of fructose is approximately 1.5 times higher than that of sucrose, and at 60 ºС fructose is 20% less sweet than sucrose.
Glucose, also called dextrose or grape sugar, is one the most widespread energy sources in living organisms. Glucose is a basic element in most carbohydrates; in nature, it is found in many kinds of fruits, berries, root crops, cereal crops, and starchy vegetables.
Galactose (derived from the Greek word root γάλακτ-, meaning “milk”) is a monosaccharide contained in lactose. It can be found in dairy products, avocado, sugar beet. It has about the same sweetness level as glucose.
Disaccharides are carbohydrates, the molecule of which consists of two residues of monosaccharides (we'll be specifying these in parentheses).
Sucrose (glucose + fructose) is exactly what we refer to as table sugar. It is a disaccharide that is commonly found in nature, including many fruits and berries. The highest sucrose content can be found in sugar beet and sugar cane, which makes them the primary raw materials in the sugar industry. If you'd like to learn more about it, you can again refer to Collier's Encyclopedia. In various comparison tables, the relative sweetness of sucrose is normally expressed as a "1” and sometimes “100”, which makes it a maximum sweetness standard of sorts.
Maltose (glucose + glucose), also known as brewing sugar. It is contained in sprouted barley, rye and other grain crop seeds in large amounts. Besides, there are reports that it has been found in tomatoes, pollen, and nectar of some plant species. It is widely used in China and Japan where it is extracted from rice.
Lactose (glucose + galactose); the main sources of lactose are milk and dairy products. On average, the content of lactose in animal milk is 4-5% (except for deer milk that has less than 3% of lactose content). Accordingly, the share of lactose in dry and condensed milk increases, and in fermented dairy products it decreases because lactic bacteria convert it into lactic acid.
It's worth noting that the types of sugar mentioned above are not the only ones that can be found in nature; those are just the most common types. For instance, there's also trehalose, xylose, and cellobiose. In this article, we're also leaving out various polysaccharides that are not directly related to sugar but are still carbohydrates that bartenders use every so often (for example, pectin, starch, agar-agar).
Besides, it's important to understand that not only sugar but also a number of proteins have a sweet taste: thaumatin, moneline, brazzein and pentadin (both were found in the fruits of the West African plant Pentadiplandra brazzeana; they are 2000 and 500 times sweeter than sugar, respectively), aspartame and other types. Polyatomic alcohols are also sweet—glycerin, sorbitol, xylitol, isomalt, just to name a few. And since we've mentioned the sweet taste, here's a graph illustrating the relative sweetness of some elements:
The sweetness, as seen in the graph, is relative not only in comparison with sucrose but also in other parameters. The sweetness of sugars depends on temperature (see the example of fructose above), pH, physical properties of the system, and other factors.
Invert syrup deserves special mention; it is obtained from sucrose that undergoes the hydrolysis process and breaks down into glucose and fructose as a result. Sugar crystallization in an invert syrup is a slow process, so this kind of syrup is widely used in the alcohol and food industries. At home, you can make a partially inverted syrup by heating sugar syrup and adding ingredients like citric acid to it. By the way, if you simply boil your sugar syrup for a long time, sucrose inversion will occur, too; but this process is so slow that the syrup you’ll make at the bar will contain a negligible amount of invert sugar.
BRIX: what it is and why you should measure it in all liquids you store at the bar
BRIX expresses the ratio of the weight of sucrose dissolved in water to the weight of the solution; it is measured in ºBx. To calculate BRIX, various refractometers are used. Aside from the Brix scale, three other, similar scales exist: the Balling scale, the Plato scale, and the Oechsle scale. The Plato scale is mostly used in the brewing industry; the Balling scale is quite outdated but it's still in use in the winemaking industry of South Africa. The Oechsle scale is widely used in the wine industry of Germany, Switzerland, and Luxembourg.
The problem here is that a refractometer does not directly measure the amount of sugar in a solution. Instead, it measures the refractive index in an environment. So, if a solution contains any substances other than sugar and water, then ºBx will reflect the concentration of sugar and other particles in the solution. For example, if you're trying to measure Brix in a solution composed of sugar, water, and alcohol, you won't achieve any reliable results, because alcohol is less dense than water, and that lowers the Brix value. Temperature also impacts this metric: since liquids expand during heating, their refraction indexes get lower as the temperature increases (the Brix scale refers us to 20ºС). The Brix scale is only useful when measuring the amount of sugar in fruit or vegetable juices and other non-alcoholic drinks (keep in mind that temperature is an important factor, too).
Sugar and syrup types
Aside from beet-root sugar that we use most often, there are many other interesting sources of sweetness. Here we're going to cover those that may be of interest at the bar (except for pure glucose and fructose — these types have already been covered above).
Honey was one of the main sources of sweetness in Europe up until the 16th century when it was replaced with cane sugar and other, more neutral types of sugar. The taste of honey can be very different depending on what nectar sources the bees were using. The main components of honey are: water - 13-20%, fructose - 38%, glucose - 31%, sucrose - 1-1.5%, other types of sugar - 7-9%, acids and minerals - 2%. Honey also contains protein—that's why a foam appears during shaking. In rare cases, honey can be poisonous if the bees collected it from plants that have poisonous substances in their pollen and nectar (rhododendron is one example).
Maple syrup and palm sugar
Maple syrup is made by evaporating maple sap for a long time, thus reducing its volume by approximately 40 times. Maple syrup was the main sugar source for North American indigenous tribes who would make the syrup by means of either heating and evaporating or freezing. As of today, Canada and the US have agreed on three maple syrup grades: “A Grade” has 4 sub-categories into which syrups are classified based on their color and taste; “Processing Grade” includes syrups that do not qualify for the first category; “Substandard” is the lowest grade. The sugar content is 65-67%, of which about 62% is sucrose.
Palm sugar is extracted and produced from various tropical palm saps using a similar method. The source materials are usually palm tree trunks, sometimes flowers. The sap is evaporated and turns into a syrup (sometimes also called “palm honey”) or a crystallized mass (sugar)—in India they call it gur, and in America and Europe, it's called jaggery. The most common palm tree species are coconut palm, fig palm, Arenga (sugar palm), palmyra palm, and nipa palm.
To make agave syrup, they use several kinds of agave, including Agave tequilana and Agave salmiana. The resulting sugar compositions will be different depending on which kind of agave you're going to use. The syrup obtained from Agave tequilana is mostly composed of fructose (56-60%), glucose (20%), and a small amount of sucrose; the other type contains more sucrose (28-32%), while fructose and glucose are in smaller amounts. The production methods are also different. In the case of Agave tequilana, first, the plant’s leaves are cut off, then sap is extracted from its central part (the piña); this sap is then boiled down into syrup. At its first stage, the process of making syrup from Agave salmiana is similar to the pulque-making process. When agave grows a shoot (that is, its potential flowers) it is removed to create a bowl-shaped vessel in its place, into which agave's juice (aguamiel) begins to flow. If the juice is left inside the plant for 24 hours, it gets fermented into pulque. But for syrup-making purposes, the juice is collected every day to prevent fermentation; it is then also boiled down into syrup. There is another way to make a syrup without heating—that one involves enzymatic exposure.
Cane sugars and molasses
Sugar cane is one of the main sources of industrial sucrose. There are several types of cane sugar that differ by the extent to which the sugar is refined. Here is a list of some of the cane sugar types:
- Demerara is a type of sugar that is obtained when the first stage of sugar cane juice crystallization is completed; its color ranges from yellow to light brown.
- Muscovado is a type of practically unrefined cane sugar that is dark brown in color. It contains quite a lot of molasses which makes the taste flavorful and rich.
- Molasses is a by-product of the sugar production process. It is a liquid substance that can have a broad taste profile (from sweet to bitter) as a result of long caramelization and other chemical processes, also depending on the production stage at which it was obtained.
- Piloncillo: in Central America, evaporated sugar cane juice is widespread; it is sold in the form of solid blocks or cones. It has different names depending on the country—for instance, in Mexico they call it piloncillo or panela. Sugar caramelization levels also vary, which affects the color and taste.
Corn syrup and treacle
On top of obtaining sugar syrups from juices that contain mono- and disaccharides, there is a less obvious way: you can also extract sugar from starch. Starch is a mix of amylose and amylopectin polysaccharides, the monomer of which is alpha glucose. When affected by ferments or heat and acids, starch undergoes hydrolysis; glucose is one of the results of this process. In simple terms, we can say that the same process occurs in our bodies when we eat starch. The industrial-scale production of syrups from starch-containing ingredients began already in the 19th century. There are two most common varieties of such syrups: corn syrup and treacle.
Corn syrups are commonly used in cooking and the food industry. The standard corn syrup consists mostly of glucose, but there are also corn syrups that contain a great amount of fructose or maltose.
The word “treacle” may be used to refer to corn syrup, maltose syrup, or any other syrups obtained from starch, as well as molasses. In everyday language “treacle” may mean not only syrups obtained as a result of starch hydrolysis but a number of other things as well.
One would think that sugar syrup is the simplest kind of syrup. But there are quite a few nuances to it, so before grabbing a saucepan or a blender it will be helpful to gain some understanding of the chemical and physical processes associated with syrup-making.
There are two main ways to make a simple sugar syrup: you can either mix sugar with water in a blender or do the same thing using a stewpan on a cooker. Both methods are good, but it's important to understand that you'll get two different syrups in the end.
Sucrose (just like fructose, glucose, and maltose) is water-soluble, and its solubility depends on temperature.
As seen in the graph, at 20 ºС you can dissolve 200 grams of sugar in 100 grams of water, and almost 500 grams at 100 ºС. This means that by simply mixing sugar with room temperature water it is possible to make a 2:1 syrup without having to heat it (alternatively, you can use a blender). But you should keep in mind that these data are only true if you use pure sucrose. For brown sugar, for instance, the coefficients will be slightly different.
It's up to you to decide which sugar syrup is better. If you make a syrup without heating, the obvious advantage is that you don't have to wait until it cools down. Also, if you choose to boil it, some liquid will evaporate making the syrup's taste less stable—because it's difficult to accurately determine how much liquid has evaporated (the best option would be weighing the substance before and after boiling). At the same time, heating is good because the syrup gets pasteurized during boiling, which may prolong its shelf life (provided of course that you don't put your newly cooked syrup in a dirty bottle or mix it with old syrup—if you do, be prepared to see different forms of life appear in it).
At the bar, three most common types of sugar syrup can be found, all of which differ by the amount of sugar they contain: 1:1, 3:2, and 2:1. There's a misconception that the 2:1 syrup is two times sweeter than the 1:1 kind, but that's actually not true. The concentration of sugar in the 1:1 syrup is 50%, while the 2:1 type is 66% sugar, which is only 16% more than the regular syrup. There is no “right” choice when it comes to choosing syrup concentration, it all depends on what your priorities are. We prefer the 3:2 type because it is the optimal ratio of the syrup viscosity to the amount of water contained in it.
While we're on the topic of syrups, we have to mention oleo-saccharum and the “cold” method of making syrups from fruits and berries. Initially, oleo-saccharum was only used to flavor sugar with orange or lemon peel. The trick was to mix orange or lemon peel with sugar and let the mixture stay for some time. Today, this method is used at practically every bar; peel is also commonly replaced with other products that contain essential oils. There is another, similar method: you can soak fruits and berries in sugar syrup. This second method is mainly used in industrial production to either preserve products more effectively or manufacture candied fruits and berries. The physical processes that occur when we use these methods are based on osmosis. When you put a fruit into a concentrated sugar solution, the amounts of water contained in the syrup and the fruit are different. As the system is trying to balance itself, water (as well as minerals, vitamin, fruit acids, flavoring components, and other substances) is leaving the fruit through its semi-permeable cell membranes, while the sugar contained in the syrup migrates into the fruit. This process is called osmotic dehydration. Depending on the concentration, type, and temperature of the syrup, as well as the duration of the syrup-fruit interaction, the results may be different. The optimal parameters are the following: syrup temperature - 30-50ºС (beyond 50ºС, the taste and texture of fruits and berries start to change significantly), sugar concentration - 60-70 ºBx. You can conduct an experiment to figure out which parameters are optimal for you specifically. You should bear in mind that a 10ºС increase in temperature will make the reaction 2-3 times faster. This means that if you consistently keep the syrup's temperature at 40ºС, it can be ready in 2 hours, but at 20ºС the process will take at least 8 hours. Finally, by cutting the fruits into thinner slices you will increase the interaction surface, which also makes the process more efficient. By the way, alcohol can also be involved in the osmotic dehydration process—to some extent, this process occurs when you make various infusions
Lastly, I'd like to mention gomme, or gum syrup. Gomme is a kind of sugar syrup that additionally contains gum arabic, an ingredient that affects the syrup's viscosity and the texture of the drink, making it denser and larger in volume. Gum arabic is basically dry acacia resin. You can easily make this syrup yourself if you have gum arabic and sugar. First, you need to dissolve gum arabic in hot water (because in cold water it dissolves very poorly); you can use a blender to ensure that the mixture is homogeneous. It's recommended that you also strain it. Then mix the solution with hot sugar syrup.
There is a great number of sugar types that you can you use at your bar in a variety of ways, and we hope that you'll be able to apply the knowledge we've shared in this article. We encourage you to do your own research on this subject, experiment with different methods and ingredients, and share your findings with the community.
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- Dave Arnold. Liquid Intelligence: The Art and Science of the Perfect Cocktail.
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