From Glucose to Sucrose: Understanding the Range of Sugars Fermentable by Yeast

In the realm of tiny microorganisms, there exists a magical being with the power to transform the ordinary into the extraordinary. We’re talking about none other than yeast – nature’s alchemist that transforms sugar into the nectar of life, creating bubbles of carbonation and infusing our taste buds with the elixir of fermentation. But have you ever wondered about the full extent of yeast’s sweet magic? Join us on a voyage of discovery as we delve into the fascinating world of fermentable sugars and unveil the diverse range on which yeast can work its transformative magic.

In this extraordinary exploration, we transcend the ordinary sugars we know and venture into the realm of unexpected sweetness. From the familiar sucrose to the lesser-known maltose and beyond, we dive deep into the vast spectrum of sugars that yeast can ferment. Prepare to be mesmerized by the scientific wonders and culinary possibilities that lie within the transformative powers of yeast. So buckle up and open your mind to the enchanting world of fermentable sugars – a realm where yeast reigns supreme and taste takes on an extraordinary twist.

Understanding Fermentable Sugars

Yeast is a remarkable microorganism that has the ability to break down sugars through a process called fermentation. During fermentation, yeast consumes sugars and converts them to alcohol, carbon dioxide, and various flavor compounds. However, not all sugars are readily fermentable by yeast, and different sugars can affect the taste, aroma, and mouthfeel of the final product.

Common Fermentable Sugars

  1. Glucose and dextrose: Glucose, also known as dextrose or corn sugar, is a monosaccharide that yeast can easily ferment. It is commonly derived from converted starches, such as malted grains, and is often used in brewing to increase the alcohol content of beer.
  2. Maltose: Maltose is a disaccharide consisting of two glucose molecules. It is completely fermentable by yeast and contributes to the specific gravity of the brew. Maltose is naturally found in malted grains and is a key ingredient in beer brewing.
  3. Fructose (fruit sugar): While fructose is fermentable by yeast, its excessive use in brewing can lead to off-flavors. It is typically found in small amounts in all-malt beers and can add a subtle sweetness to the final product.
  4. Sucrose (table or cane sugar): Sucrose is a disaccharide consisting of one glucose molecule and one fructose molecule. Before yeast can ferment sucrose, it must be broken down into its constituent sugars. Sucrose is commonly derived from sugar beets or sugar cane and is widely used in brewing. However, excessive use of sucrose can result in a cidery flavor if not fermented properly.
  5. Invert sugar: Invert sugar is sucrose that has been hydrolyzed into its constituent sugars, glucose and fructose. This can be accomplished by acid treatment or the use of invertase enzymes. Invert sugar is often used in brewing to lighten the body and color of beer.
  6. Honey: Honey is a complex mixture of sugars consisting primarily of glucose and fructose in inverted form. Yeast can ferment honey, but its composition can vary depending on the source, season and region. Honey can add unique flavors and aromas to the final product.
  7. Belgian candy sugar: Belgian candy sugar is sucrose that has been slowly crystallized to form rock candy. It comes in a variety of colors, from light to dark, and is commonly used in Belgian beer brewing. Candy sugar can add color, flavor, and overall complexity to high gravity beers.
  8. Lactose or milk sugar: Lactose is an unfermentable sugar often used in the brewing of milk stouts. It adds sweetness and body to the beer because normal beer yeast cannot ferment lactose.

Factors that Influence Taste: Beyond Sugar, the Art of Creating Enticing Flavors

While sugars play a significant role in influencing the taste of the final product, there are several other factors that can contribute to the overall flavor profile of a fermented beverage. Here are a few additional factors to consider:

  • Yeast strain: The choice of yeast strain used for fermentation can have a profound effect on the flavor characteristics of the final product. Different yeast strains produce different levels of esters, phenols, and other flavor compounds that can add fruity, spicy, or even funky flavors to the beverage.
  • Fermentation temperature: The temperature at which fermentation takes place can greatly influence flavor development. Higher fermentation temperatures can promote the production of fruity esters, while lower temperatures can result in a cleaner and more subdued flavor profile.
  • Hop selection and timing: Hops are commonly used in brewing to add bitterness, aroma and flavor to the beer. The selection of hop varieties and their timing during the brewing process can contribute to a wide range of flavors, from floral and citrusy notes to earthy and herbal undertones.
  • Water composition: The quality and mineral composition of the water used in brewing can affect the flavor of the final product. Different regions have different water profiles that can affect the overall flavor and mouthfeel of the beverage.
  • Ingredients: In addition to sugar, brewers often incorporate adjunct ingredients such as fruits, spices, herbs, and even wood chips into their recipes. These adjuncts can introduce unique flavors, aromas, and complexities that enhance the overall sensory experience.
  • Fermentation time: The duration of fermentation can influence the flavor development and character of the beverage. Longer fermentation times can allow for more thorough yeast activity and the development of additional flavor compounds.
  • pH levels: The acidity or alkalinity of the brewing environment can affect the flavors perceived in the final product. pH levels can affect the balance of sweetness, bitterness, and acidity, affecting the overall flavor profile.
  • Sanitation and fermentation control: Proper sanitation and fermentation control are critical to preventing off-flavors caused by unwanted microbial activity or contamination. Maintaining a clean and controlled fermentation environment helps ensure the desired flavor outcome.

It’s important to note that these factors interact and should be considered holistically when trying to achieve a specific flavor profile. Brewers carefully manipulate these variables to create a balanced and harmonious flavor experience in their fermented beverages.



What sugars can yeast ferment?

Yeast can ferment several types of sugars, including glucose, dextrose (corn sugar), maltose, fructose (fruit sugar), sucrose (table sugar or cane sugar), invert sugar, honey, candy sugar, and lactose (milk sugar).

Which sugars are fermentable?

Fermentable sugars include glucose, dextrose, maltose, fructose, sucrose, invert sugar, honey, candi sugar, and lactose. These sugars can be broken down and converted to alcohol and carbon dioxide by yeast during fermentation.

Are all sugars fermentable by yeast?

Not all sugars are fermentable by yeast. While yeast can ferment a wide range of sugars, some sugars, such as non-fermentable sugars like certain types of complex carbohydrates, cannot be metabolized by yeast and therefore remain unfermented in the final product.

Can yeast use any sugar?

Yeasts feed on sugars and starches, which are abundant in bread dough! They turn this food into energy and release carbon dioxide gas as a result.

What sugars can yeast eat?

Summary: Yeast cells do not normally eat complex sugars or carbohydrates, only simple sugars like glucose and sucrose. Researchers have now added genes to yeast that allow it to eat more complex sugars, in particular the two-, three- and four-glucose molecules called cellodextrins.

What sugar is not fermentable?

Lactose and maltodextrin are also natural non fermentable sweeteners that have been used in brewing and winemaking in the past. They are not as sweet as sugar and generally add more mouthfeel than sweetness.

Which sugar is best for yeast fermentation?

Clearly, maltose is the best for yeast metabolism. Remember, yeast is made of two glucose molecules. Glucose (aka dextrose) is a close second. Fructose is in third place.

Which is the most fermentable sugar?

Pure sucrose is the reference standard for all fermentable sugars because it contributes 100% of its weight as fermentable extract.

Is brown sugar fermentable?

Brown sugar is an unrefined or partially refined sugar that contains some residual molasses. It comes in light and dark varieties and can lend subtle caramel notes to your beer. Like table sugar, brown sugar offers 46 ppg and is nearly 100 percent fermentable.