having a hard time understanding the addition of sugar to increase alcohol/dry out

take this recipe for example just as a regular base line example.

based off of beer calculus from hopville.

3 lbs 5 oz pilsner LME (3.3 lbs of LME)
2 lbs wheat DME

using a wyeast Kölsch liquid yeast and proper pitch rate with starter per mrmalty.com and also using a yeast nutrient. with a 75% attentuation (per beer calculus)
OG = 1.042 and FG =1.010 4.3 ABV


now take same said recipe and add 2 lbs of brown sugar
3 lbs 5 oz pilsner LME (3.3 lbs of LME)
2 lbs wheat DME
2 lbs brown sugar (added to last 10 minutes of boil)

using same yeast, amount, starter, and nutrient...

OG = 1.060 and FG = 1.015 6.0 ABV (again based off of hopville beer calculus)

my question is: Will final gravity be more closer to 1.010?? 6.7 ABV??

I know that beer calculus is an estimate, but from what I gather
It's my understanding that sugars (brown/table/corn) ferment completely out of solution to 100%, even if your attentuation is 75% of your sugars derived from malt. Is this true or am I misunderstood??

the reason I am adding sugar in my recipe is to get the alcohol up but still retain a lower FG. Just trying to make sure I understand and make proper adjustments to my recipe based off my knowledge. Any guidance is welcomed thank you in advance - Shawn

It looks like the calculations that the program(s) you are using make a simple estimation of Apparent Attenuation.

Basically if you take your gravity points and divide by 4, you will get the approximate Terminal Gravity.

For the SGs you provide:

1.042 or 42/4=10.5, therefore an approximate FG is 1.0105
1.060 or 60/4=15, therefore an approximate FG is 1.015

This doesn't mean your FG will be what is estimated, there are many factors that affect AT, number one being the type of yeast.

Hope that helps.

As you can see from your calculations the addition of the sugar did in fact raise the Og correctly but yes, calculating the ultimate FG is more difficult due to all the variables involved so it is more of an estimation of where it should wind up but the numbers look pretty close to what you should expect.

I am not totally sure about this, but I would think that adding a “reasonable” amount of simple sugar to a “normal” gravity batch will generally result in a similar FG, i.e. the total malt sugars that would have been fermented will still ferment, and then the yeast will eat up nearly all of the simple sugars. Of course the yeast don’t pick and choose so they will eat what they can until the alcohol is too high or the conditions become unfavorable and then drop out of the race, but in this situation we are talking about “reasonable” and “normal” levels.

It seems as though your recipe is within the normal limits of the yeast’s capabilities. If you use a nice starter of healthy yeast and aerate properly, I think you will end up with a nice dry Kolsch with an FG closer to 1.010 that 1.015. In fact I think it will be nice and tasty, a Kolsch is supposed to be dry. If you were trying to get to 12% ABV it might be another story.

Like I said I don’t have any scientific background on this, but I have added up to two pounds of plain table sugar to brews before, and they did not stop fermenting 5 points higher than what I expected it to sans sugar.

I guess it is time to brew and see where I end up!! but thanks kpr121 from what I read from your post is exactly what I know/am aware of and what I have gathered from my research but wasn't sure....only one way to find out!! either way 1.010 or 1.015 I'll be close.

I don't believe brown sugar gets 100% dissolved. Only honey is 100% dissolved which is what I've added in past beers to boost the OG but have to be careful on variety and if processed or not. Don't want those off flavors

Yes, and also need to think about this – A beer can be 1.020 and still taste “dry”…. a lot of times when people think a beer is too sweet its really the unfermentable malt sugars they are tasting in relation to the bitterness that is provided by the hops. It is all relative. I think you will be satisfied with your results on this one. Maybe increase the IBUs a little to obtain a similar ratio (of course you have to be careful with this if you are trying to stay within style).

Let us know how it ends up. That is, if you are actually making this recipe and not using it as a hypothetical.

well the recipe is hypothetical, but that is my base as far as fermentables go, I'm also adding some specialty grains.

using Hallertau 4.0 AA and German select 5.8 AA for a IBU of about 25. I will let you know how it turns out.