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I was enticed to buy one kg of brewing sugars for my home brew. It was said that it would dry out the taste of the beer. I would like to know what effect adding one kg of dextrose would bring to 20 liters of wort?

I would like a higher gravity and some of the dry taste you might associate with cider.

Neil Meyer
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2 Answers2

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Dextrose: AKA glucose, corn sugar is a monosaccharide the easiest form of sugar for yeast to consume. Not to be confused with Dextrins, which are not fermentable.

1KG (2.2LB) of corn sugar added to 20 liters (5.28gal) of wort will raise the OG .019 points.

Many recipes make this addition in the boil though usually not more than 1lb per 5 gallons. This gives the gravity a nice boost for some clean ABV increase with a slight dry character. But is usually balanced with the malt and goes unnoticed.

If yeast is given too much glucose it will basically forget how to consume the larger sugars unless the pitch is very large. What happens is the yeast will feed and reproduce from the glucose first and literally lose the pathways to more complex sugars from cell division scars and then be unable to consume very much of the complex sugars. Also the ABV raises faster than the cell walls can adjust to tolerate. Leaving you with an under attenuated sweet beer.

If you plan on adding more than 1lb into 5 gallons I recommend 1lb into the boil, and the second 1.2lb with nutrients as a feeding when fermentation starts to slow.

Evil Zymurgist
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    OK so maybe just half a kg. – Neil Meyer Jun 10 '16 at 06:33
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    Great answer. I'd like to add this point about "dryness". Adding sugar to a recipe does not create dryness per se. Using sugars to create a drier finish in a beer is done by swapping some of the malt fermentables with the sugar. This leaves the recipe at the same intended OG and ABV, but creates a 'drier' flavor profile and finish. There are limits. Adding sugar on top of an already high OG beer (whether as an addition to boost ABV or as a replacement for dryness) requires great yeast management and fermentation otherwise the benefit of the sugar is lost as the yeast tends to underperform. – brewchez Jun 10 '16 at 11:02
  • I frequently have added more than a lb. to the boil with absolutely no adverse effects. – Denny Conn Jun 12 '16 at 09:41
  • @DennyConn oh for sure. It's not uncommon to put 4lb sugar into 5gallons of must for an Applewine. Or even big beers, it's just another ball game that takes a second set of skills for super high gravity brewing. 1lb to 5g is really just a threshold in most recipes before you have to consider significantly changing brewing and fermentation techniques. – Evil Zymurgist Jun 12 '16 at 15:00
  • I just haven't found that I have to change anything when I add up to 20-25% of total fermentables as sugar. I just follow my normal brewing practices. – Denny Conn Jun 16 '16 at 15:18
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dextrose ferments cleanly with little residue, except alcohol and CO2! Malt (ie. extract) is composed of fermentable sugars and unfermentable carbohydrates (eg maltodextrins). The unfermentabel carbs contribute to the beer turbidity and "mouth feel". They also increase the calorie count of the beer. The fermentable sugars ferment much like brewing sugar (dextrose).

So if one wants a light but strong beer, the malt is balanced with more dextrose. If one wants heavy but not so strong ale then malt and no sugars are used. That is not a technically precise definition but it gives an idea of how one can be used with the other

barking.pete
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