October 28, 2021

Sweeteners: How do they affect the flavour of your coffee?


While many of us enjoy drinking our coffee with no milk or sugar, there are plenty of people out there who add something to sweeten their cup. This might be sugar, honey, or artificial sweeteners. 

There are so many options for people looking to add sweetness to their cup of coffee. But how exactly do these substances affect cup profile? And how does sugar differ from its alternatives? 

To learn more about the science behind adding sweeteners to coffee, I spoke with three experts. Read on to find out what they had to share.

You may also like our article on the age-old habit of adding sugar to coffee.


Why do people sweeten their coffee?

There’s plenty to be said for unsweetened coffee. However, it’s not uncommon for people to find the flavour of coffee to be too intense or acidic, especially for lower-quality coffee. For some people, the solution to this is to add something sweet. 

Jamie van Dam and Les Kuan are administrators and instructors at the Canadian Barista Institute. They say that because drinking coffee is such a subjective experience, there’s no right or wrong way to enjoy it.

“For most people, coffee is bitter because they are drinking poorly roasted, prepared, and brewed beans that are also stale,” they say. “These factors lead to an extremely bitter cup, which most people drink for [the caffeine].”

Putting sweeteners into either hot or iced coffee makes the beverage smoother and more palatable for many coffee drinkers – especially those who don’t drink lots of coffee.

They add: “There are some people who get used to it and drink coffee black without sugar. However, this tolerance doesn’t change the fact that any stale or poorly roasted coffee is still likely to be flat, intense, or bitter.”

Laura Christian is a Senior R&D Manager at La Colombe Coffee Roasters. She agrees with Jamie and Les, noting that for some people, sugar and milk work in harmony with some of the flavours of coffee.

“[Darker roasts] can be bold, bitter, and astringent,” Laura says. “Adding any type of sweetener can offset some of those more pungent flavours and mellow the coffee out a little.”


Types of sweeteners and how they affect coffee flavour

We know that coffee offers a world of variety as far as flavour is concerned, thanks to origin, terroir, processing, and roast profiles. This is why some coffees are naturally sweeter than others, and the flavour will vary depending on these and other factors.

While the selection of sweeteners might not be as extensive, sugar is far from the only option. The easiest way to separate them is to break them down into three categories: sugar, artificial sweeteners, and natural sweeteners.

Sugar is most often found in one of three forms: white, brown, or raw.

White granulated sugar is generally used to sweeten coffee without drastically altering its overall flavour profile. The same is true of raw sugar, which is a lighter flavour.

However, brown granulated sugar has a heavier flavour which is caused by adding molasses during the production process. This adds slightly more complexity to the sweetness and causes the most drastic change in a cup of coffee.

Beyond sugar, there are also artificial sweeteners, which became prominent in the 20th century. They can be applied to all types of products, from coffee and tea to sugarless soft drinks. Many people switch to artificial sweeteners to cut down on their sugar intake, for a number of reasons.

Laura says: “There are a lot of different products on the market with different chemical compositions, recommended usage levels, and flavours.”

The four most commonly used artificial sweeteners are:

  • Sucralose (Splenda)
  • Aspartame (Equal, Nutrasweet)
  • Saccharin (Sweet’N Low, Sugar Trim)
  • Stevia (SweetLeaf, Truvia)

Jamie and Les add: “Aspartame and saccharin have no calories and sucralose has some calories, but much fewer than sugar because it is technically a sugar-based alcohol.”

Stevia is often perceived as a more “natural” option, but Jamie and Les point out that it’s still a manufactured product.

“Stevia is a plant, the leaves of which are sweet. However, you can’t just grind leaves into your coffee; it has to be extracted and concentrated first,” they say. “This so-called natural sweetener actually needs to be separately synthesised and processed.”

The third category of sweeteners includes products that are more true to their “natural” label than Stevia. Some of these include honey, maple syrup, and molasses. 

Other natural sweeteners include things like fruit purees and juices, agave nectar, and syrups derived from other plants. These options are most likely to drastically affect the cup profile of coffee, depending on which you add. 

espresso and water

The science behind sweetness

So, which compounds in sugars and artificial sweeteners actually alter the taste of your coffee?

Sugar is a carbohydrate that is made up of carbon, oxygen, and hydrogen atoms. There are three main types of sugar, which are categorised by how these three atoms are arranged. These are monosaccharides, disaccharides, and polysaccharides.

Monosaccharides are what we know as simple sugars. These include glucose, fructose (found in honey and fruits), and galactose (a milk sugar). 

Disaccharides are more complex, and include sucrose and lactose. Monosaccharides and disaccharides include most of the sugars we know that “sweeten”. For example, sucrose is what we know as “classic” sugar, and it is derived from either sugar cane or beets. 

Polysaccharides, however, include starches, dextrins, and cellulose. These are often found in the fibres of plant foods and are the most fundamental sources of energy and fibre in most diets.

Artificial sweeteners are a bit different. They’re widely labelled as sugar substitutes or non-nutritive sweeteners because they contain fewer calories than sugar, or none at all. These sweeteners are processed and refined during their manufacture.

“Most, if not all of them, are marketed by how they can be used instead of sugar,” Jamie and Les say. “For example, some are typically a one-for-one substitution, like coconut, turbinado, or demerara sugar. 

“Some are high-intensity sweeteners that can be used at drastically lower levels to contribute the same amount of sweetness as sugar. Classic examples are acesulfame potassium, aspartame, and sucralose.”

No matter if you are using sugar, artificial sweeteners, or natural sweeteners to alter your cup profile, there will be interesting interactions taking place in your cup. 

However, science suggests that aside from sweetness, sugar actually has a number of other profound effects. According to Yale Scientific, it does far more than just sweeten your cup.

The publication says: “According to findings, sugars increase the water solubility and concentration of single caffeine molecules, while decreasing that of caffeine oligomers – multiple caffeine molecules joined together. 

“Additionally, the sugar itself has energy boosting effects that have to be considered.”

brown sugar, white sugar, and coffee

When to add or skip the sweetener

As with all coffee additives, the decision to add sweetener is typically subjective, and left to each individual’s preferences. There are no set rules to follow.

“Coffee is super subjective, and everyone has their own preferences when it comes to how sweet you want your beverage,” Laura says. “Our goal is to make coffee approachable. In our cafés we don’t banish people to the ‘sugar island’, but instead encourage them to fix their coffee just the way they want it, right at the bar. 

“Some coffee purists may encourage coffee drinkers to not add any sweeteners (or milk) to high-quality coffee. At La Colombe, we would encourage you to drink your coffee however you like it.”

Jamie and Les, meanwhile, believe that the bigger issue is why people need sugar at all. According to them, there are better ways to curb your dependence on sweeteners.

They say: “Stop drinking coffee that tastes so bitter. You can do this by buying high-quality beans that are not over-roasted (burnt and dark), prepared by people who know how to [get the best out of their beans].

“If you do all of this, your coffee will be less bitter and you will use less sugar or sugar substitutes because you won’t need to hide the taste.”

stirring coffee

While sweeteners can certainly balance out the bitterness of coffee and alter overall flavour, each individual should always prepare their coffee in the way they prefer. The best way to find out what you like most is to experiment.

At the end of the day, the thing to do is make sure that you buy good, high-quality beans that have been fairly and ethically sourced. You might find that drinking a different roast or beans from a different origin eliminates the need for sugar entirely.

Enjoyed this? Then read our article exploring the market for coffee flavourings.

Photo credits: Pexels, Unsplash

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