calculating Lactose additions mid fermentation

[odie]

I've added some lactose during fermentation. The problem is I'm finding conflicting sources on PPG for lactose so I can estimate a "corrected" OG in order to calculate ABV when I reach FG.

If I added it before my initial OG reading then it wouldn't matter when calculating ABV at FG.

I've seen potential SG listed between 1.030 to 1.043. Also posted as 46 PPG, which I take to mean 1.046 potential SG.

I have my OG without lactose...I added a pound after a week of fermenting...so it will throw my OG/FG calculations off unless I can estimate how many points the lactose added.

 

[VikeMan]

I calculate Lactose at 43.9 PPG, based on Lactose Monohydrate being 5% water.

46.21 x (1 - 0.05) = 43.9

Also, adding lactose adds volume, which I SWAG as 0.064339 dissolved gallons per pound, based on a measurement with DME (which I know is not actually the same thing).

 

[odie]

so add about .008 to my OG reading on a typical 5 gal batch? maybe .009? or there abouts?

 

[VikeMan]

Oops. Deleted. Was answering wrong thread.

ETA: Yeah, about 0.009, rounded.