I'm a little confused when it comes to sugars. It seems like there are a lot of different kinds and they come in many different forms. What affects to different sugars have on brewing? Do they impart different characteristics or are they all pretty much the same?

  • Fructose
  • Glucose
  • Sucrose
  • Dextrose
  • Maltose
  • Lactose

and any other ones I may be missing.

Also, what are the common sugar sources composed of and what makes them different (what bad/good flavors or characteristics can they impart in your beer)?

  • Malt
  • Corn sugar
  • Honey
  • Table sugar
  • Candi sugar
  • Corn Syrup
  • Molasses

again, mention any other ones I may be missing.

  • +1 because I'd really love to find a good reference for this. Commented Nov 18, 2010 at 21:25

1 Answer 1


Wort (from 100% malt) is typically:

  • 45% Maltose
  • 20% Dextrose
  • 15% Maltriose
  • 10% Glucose/Fructose
  • 5% Sucrose
  • 5% other

You can read more about adjuncts and their fermentability here.

  • 1
    I should probably also add: maltose, dextrose, glucose, fructose and sucrose are completely fermentable. Maltriose fermentability depends on the strain of yeast.
    – Brandon
    Commented Nov 18, 2010 at 19:53
  • 1
    I think most lager yeasts can break down Maltotriose, but most ale yeasts cannot, correct? I think that's why many lager yeasts have the potential to produce a dryer beer ... because they can break down a higher percentage of sugar and achieve a higher attenuation. Commented Nov 18, 2010 at 20:19
  • 1
    What about lactose, can anything break that down? Also, if all of these sugars can be broken down, what can brett break down? I've read in a few places that brett breaks down more sugars than other yeasts can.
    – Room3
    Commented Nov 18, 2010 at 20:27
  • I'll have to check my yeast book, but I think maltriose fermentability falls within a limited range, even for lager yeasts. Lactose is 76% fermentable. And yes, Brettanomyces can process more sugars than Saccharomyces (ale & lager yeast), but it's hard to find documentation on fermentability of various sugars. When I've brewed with Brett, I have achieved apparent attenuation of 95-100%.
    – Brandon
    Commented Nov 18, 2010 at 20:47
  • 1
    Normal brewers' yeast lacks the ability to break down lactose. Furthermore, they are unable to eat galactose so at best it can only be fermented up to 50%. There are GM strains and some wild yeasts which can do better, though. As an aside, some strains of lactic bacteria will first break down the lactose leaving glucose or at least some half digested by-product which the yeast can eat.
    – user61
    Commented Nov 20, 2010 at 2:18

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