Calculating ABV after adding corn sugar to primary

[loljoewtf]

Hey guys

I brewed a barley wine on Sunday. The grain bill ended up being 24lb. I used Wyeast Irish Ale yeast and was told I should pitch a second yeast and add some sugar to really finish the fermentation. My measured OG was 1.120 (Low efficiency on that brewday ) and FG should be around 1.032.

I plan to add 2lb of sugar (8% of grain bill) when I pitch the second yeast (WLP099 Super High Gravity Ale yeast) to the primary. How can I tell how this will affect the ABV? I've done a bunch of searching and can't find the answer. Do I need to stir it up and take the gravity pre and post pitch, and then add the difference in gravity to the OG and assume the same FG to calculate the new ABV?

Any help would be appreciated!

Thanks,

Joe

 

[kosmokramer]

go to hopville and plug in the pound of dextrose for your batch size, i think it is .009 per pound in a five gallon batch. if you do two pounds add the .018 to your og

 

[loljoewtf]

Oh, I thought putting it with the malt assumed I was mashing or boiling with it. Thanks!