Corn sugar, also known as dextrose, is indeed fermentable. As a sommelier and brewer, I have had plenty of experience working with different types of sugars in the brewing process, and corn sugar is a common choice for fermentation.
When added to the boil, corn sugar can have several effects on the beer. Firstly, it can lighten the body of the beer, giving it a crisper and more refreshing mouthfeel. This can be especially beneficial for big beers that may have a heavier body. By using corn sugar, brewers can achieve a more balanced and drinkable final product.
Additionally, corn sugar can boost the alcohol content of the beer. This is because it provides additional fermentable sugars for the yeast to consume during fermentation. The yeast converts these sugars into alcohol, resulting in a higher alcohol by volume (ABV) in the finished beer. This can be particularly useful when aiming to create a stronger beer without adding excessive maltiness.
Another advantage of using corn sugar is that it can help to dry out the beer. This means that it can reduce the perceived sweetness and make the beer finish with a crisper and cleaner taste. This can be desirable in certain beer styles, such as IPAs or Belgian Tripels, where a dry finish is preferred.
In terms of the specifics, corn sugar typically yields 42 gravity points per pound per gallon (ppg). This means that if you were to add one pound of corn sugar to one gallon of wort, it would increase the gravity of the wort by 42 points. This measurement is important for brewers to calculate the potential alcohol content of their beer and to ensure they are adding the correct amount of sugar.
It is worth noting that corn sugar is 100 percent fermentable, meaning that all of the sugar will be consumed by the yeast during fermentation. This is different from other sugars, such as maltose, which may have a lower fermentability and can contribute residual sweetness to the beer.
From my personal experience, I have used corn sugar in various brewing recipes and have found it to be a reliable and effective fermentable sugar. It is easy to dissolve in the boil and is readily consumed by the yeast, resulting in a well-fermented and balanced beer.
To summarize, corn sugar, or dextrose, is indeed fermentable and can have several benefits in the brewing process. It can lighten the body of the beer, boost the alcohol content, and help to create a dry finish. Its high fermentability makes it a popular choice among brewers, and it is a versatile ingredient that can be used in a wide range of beer styles.