Malt extract vs. corn sugar to prime
TroubleShooting
Dave Ross • Philadelphia, Pennsylvania asks,
Recently,I was making a batch of Scotch ale. The recipe called for wheat DME as a priming sugar. Obviously I can experiment with anything I want in my homebrew, but I was wondering if I really needed to use wheat DME or if I could have used the amber DME I had already? Depending on the recipe, it will call for different types of DME as a priming sugar, for example, wheat, light or amber. To what extent does the use of various DME as priming sugars contribute to the flavor or color of the beer? Also, could you could explain the pros and cons of using DME vs. corn sugar to carbonate beer? What does DME do for beer that priming sugar doesn’t?
This is a question I often ask myself when reading recipes. It seems to me that using DME or saving wort for priming is a pain in the neck. The contribution of color or flavor to beer from priming sugar is insignificant compared to the flavor and color present in wort before fermentation. Even if the priming sugar added some flavor, an argument could be made for adding it before wort boiling, for example, brown sugar.
I think the best sugar to use for priming is either corn or invert sugar because they are both 100% fermentable and easy to handle. The problem with using wort or DME for priming is the inconsistent fermentability of wort. If you use DME with an unknown fermentability for priming, then it’s impossible to control the carbonation level. Commercial brewers who prime with wort measure wort fermentability before priming and base the amount of primings on this measured number.
The main difference between beers primed with DME or wort versus those primed with corn sugar is that the beers primed with corn sugar are not in compliance with the Reinheitsgebot.
Invert sugar consists of equal parts glucose and fructose. When fructose is transported into the yeast, it’s converted to glucose and enters the glycolytic pathway where it’s used as cellular fuel and ends up as alcohol and carbon dioxide. When maltose from wort is transported into the yeast cell, it’s first converted to two molecules of glucose and then follows the same biochemical pathway as the glucose from corn sugar. The only difference between wort and a corn sugar solution are the non-fermentable sugars, proteins and color compounds present in wort. These compounds are present in much higher concentrations in the original wort.
I expect to hear some strong opposition to these views, but that is the way I see it. This would be a good question to put up to an experiment followed by a blind tasting to determine what effect, if any, can be quantified by using different types of priming solutions.
