[tommymorris]

Is there a rule of thumb on how much sugar is needed to move the FG down by 1 point? I understand the advice to add sugar to decrease gravity but don’t know how much sugar is needed.

If I plug 1 lb Demerara sugar into BeerSmith it says 1.009. So 1.001 should be ~.125 lb.



Sent from my iPad using Tapatalk

But, that’s moving the SG up.

I am talking about moving the FG down when sugar is added to a brew with yeast that doesn’t process maltose. The sugar is fermented more completely so it makes a less dense volume of beer combined with the more dense volume of beer from the malt additions. In this case, the inclusion of sugar averages down the FG. But, by how much?

[tommymorris]

But to your point, BeerSmith predicts a 1050 beer with 9% Demera finishes at 1010 versus 1014 for a 1050 beer made of 100% pale malt.

[BrewBama]

Ah.  If I add a lb of sugar to an existing recipe in BeerSmith the FG goes down 3 pts.

Edit: 2-4. I tried it on several recipes and got a variation.

Sent from my iPad using Tapatalk

[Megary]

Ah. If I add a lb of sugar to an existing recipe in BeerSmith the FG goes down 3 pts.

Edit: 2-4. I tried it on several recipes and got a variation.

Sent from my iPad using Tapatalk

Can I assume you substituted the sugar for something else?

I may be thinking about this upside down but if the sugar is fully fermentable, adding sugar to an existing recipe will only increase OG and not change FG...unless you use the sugar as a substitute for malt, keeping the OG the same.

[BrewBama]

No. I just added it to a few existing recipes in BeerSmith as is. BeerSmith predicts it lowers FG 2-4 points.



Sent from my iPad using Tapatalk

[Megary]

No. I just added it to a few existing recipes in BeerSmith as is. BeerSmith predicts it lowers FG 2-4 points.



Sent from my iPad using Tapatalk

So adding sugar not only increases a recipe’s OG but also decreases the FG?  I have to be honest, that makes no sense to me. Does sugar make the rest of the grains more fermentable?

Rough examples:

10# Malt
1.050 OG
1.010 FG

10# Malt + x# sugar
1.055 OG
1.008 FG

??

How can the yeast attenuate the base recipe further?

I can understand this:

9.5# Malt
x# sugar
1.050 OG
1.008 FG

In this case you are subbing something more fermentable in for something less fermentable.

This feels like I’m failing Brewing 101. 

[dmtaylor]

Alcohol has a specific gravity below 1.000.  For instance, champagne will finish at a gravity of around 0.992.  So at least theoretically, when you are adding sugar that is 100% fermentable, you can reduce the FG accordingly, since when the alcohol is produced, the SG is not aiming for 1.000, but rather something much lower.

[Megary]

Alcohol has a specific gravity below 1.000.  For instance, champagne will finish at a gravity of around 0.992.  So at least theoretically, when you are adding sugar that is 100% fermentable, you can reduce the FG accordingly, since when the alcohol is produced, the SG is not aiming for 1.000, but rather something much lower.

Well sure….if you use science and stuff.

I was definitely under the impression that say…corn sugar…would just essentially cancel itself out.  Add the gravity, subtract the gravity.  Not add the gravity, subtract more gravity. 

Thanks for the clarification. 

[Silver_Is_Money]

When you add sugar you can reduce your grains.  Most likely reduction is some of the base malt.