Lactose (milk sugar) and large complex carbohydrates like dextrins, along with artificial sweeteners (Stevia, Sucralose, Aspartame), are sugars that yeast generally cannot ferment, primarily because they lack the specific enzymes (like lactase) to break them down into simple, fermentable sugars (glucose, fructose).
Yeast via enzymes breaks down sucrose (sugar) which it can't use into Fructose and Glucose, which are simpler sugars that it can use.
Yeast are capable of using some, but not all sugars as a food source. Yeast can metabolize sugar in two ways, aerobically, with the aid of oxygen, or anaerobically, without oxygen.
What Are Non-Fermentable Sugars?
Pure sucrose is the reference standard for all fermentable sugars because it contributes 100% of its weight as fermentable extract.
Erythritol is a non-fermentable sugar ideal for adding sweetness to bottle-carbonated beverages, like hard ciders, Because yeast can't break down or ferment this sugar it won't trigger re-fermentation, which makes it safe to add directly to bottles on bottling day.
Glucose. Glucose, also known as dextrose, is a simple sugar that is highly fermentable. It's often used in brewing because it ferments cleanly and doesn't contribute much flavour to the final product. It's readily available at brewing supply stores.
Stevia is heat-stable, pH-stable, and not fermentable. Humans cannot metabolize the glycosides in stevia, and it therefore has zero calories. Its taste has a slower onset and longer duration than that of sugar, and at high concentrations some of its extracts may have an aftertaste described as licorice-like or bitter.
Since honey is 95% fermentable, most of the sweetness in honey will be lost unless added at later stages in the boil. If you want a subtle honey flavor, add honey between 10 to 30 minutes left in the boil.
Granulated sugar acts as a fermentable sugar source that yeast converts into alcohol and helps balance the acidity and sweetness of the beer, wine or cider. Allowing you to fine-tune the flavour profile.
During fermentation, sucrose is converted into its simpler forms, glucose and fructose. Although the beverage industry once disliked the taste of the final product when using table sugar, today cane sugar, brown sugar, molasses, and inverted sugar are popular options for fermentation.
Sugarcane is a predominant crop in tropical countries and is used as raw material for several fermentation processes employing Saccharomyces cerevisiae yeasts.
There are three major factors that affect dough fermentation, namely temperature, humidity and time.
Stevia on the other hand does not ferment as well with baker's yeast due to it being a non- saccharide sweetener2. Monk fruit, like stevia, is not effective for fermenting in baker's yeast because it contains mogroside which results in minimal CO2 and ethanol production3.
Coconut Palm Sugar or Syrup – this will work well but may give sour or bitter flavours due to the high level of minerals. It may need a shorter brewing time so keep regularly tasting your brew.
Honey, maple syrup, coconut sugar, and date sugar are healthier natural sugar options. Honey, maple syrup, coconut sugar, and date sugar are minimally processed and provide small amounts of nutrients and antioxidants.
Corn Sugar (also know as Dextrose) is a fully fermentable sugar and is used as a priming sugar for natural carbonation or to boost the gravity of your brew. It's a common additive to help dry out the finish of overly hopped beers.
When crystallization begins, and glucose separates from the honey, the leftover water allows the yeast to grow and ferment the sugars. Fermentation can make the honey smell and taste different, but that doesn't make it bad or expired.
"Honey's advantages over sugar include a slightly lower glycemic index (i.e. it doesn't affect your blood-sugar levels as much)," Dr. Dixon says. 9 "It also contains more vitamins, minerals, and antioxidants, such as calcium, potassium, vitamin C, zinc, phenolic acids, and flavonoids."
In oral care products like toothpaste and mouthwash, it is used to improve taste without contributing to dental cavities, as it is non-fermentable by oral bacteria. Sucralose is also increasingly used in nutritional research and clinical trials where sugar intake needs to be controlled or monitored.
People dislike stevia primarily due to its distinct bitter, metallic, or licorice-like aftertaste, caused by steviol glycosides activating both sweet and bitter taste receptors, with individual genetics influencing sensitivity, while some blended stevia products also contain sugar alcohols that can cause digestive upset, making it an acquired taste compared to sugar.
The healthiest sugar alternatives are whole foods like fresh/frozen fruit (bananas, berries) and fruit purees (unsweetened applesauce) for natural sweetness with nutrients, while Stevia and Monk Fruit extract are excellent zero-calorie choices for blood sugar control. Other options include honey/maple syrup (use sparingly due to calories) or sugar alcohols like xylitol/erythritol, but always check labels and prioritize reducing overall sweetness, notes Johns Hopkins Medicine and Calo Blog.
People have been using fermented ginger beverages for thousands of years not only for their delicious taste but also for their tonic effect—driving out colds, boosting circulation, and calming inflammation.
If you're using table sugar it will have next to no nutrients in it. It will eventually ferment but it will be slow and end up with some serious off flavours as the yeast will be stressed.