Priming Corn Sugar is used increase alcohol content or for bottle and keg priming for natural carbonating. Corn sugar (dextrose) is good for priming bottle-conditioned beer or boosting gravity. A common addition to help dry out the finish in highly hopped beers like Imperial IPAs. Corn sugar is a fermentable sugar that produce alcohol without leaving the residual sweetness of malt extract. Adding a small amount (no more than 10% of total fermentables) will increase alcohol content with minimal impact on taste.