raise OG 2 points

[jderm]

hi all,
If I want to raise the OG of a recipe from 1.042 to 1.047, how would i do that? My current understanding is that i need to add about 25 pts to the entire batch ( 5gallons * 5 pts ). If DME yields about 40 pts per pound, could i just add a small batch of wort with 10oz DME? If this were dissolved in 2 cups of water (.125 Gallon), this would yield a gravity of 1.200. Adding this to 5 Gallons at 1.042, wouldnt this yield about (210 + 25 )/(5.125)= 45.854 pts so 1.046?
Just wondering if my logic is sound here, even if this example does miss 1.047 by a point.

thanks a lot for your help.

 

[JLem]

your logic and math look good, but I wonder why you would want to do this? adding 4 points to your OG, assuming it all ferments out (which it won't since its DME) will gain you 0.5% ABV. Is it really worth messing with a perfectly fine beer for this?

 

[jderm]

I missed a NB OG by about 5 pts -- thought i'd get my hands dirty with some troubleshooting. Any idea how a measured extract kit could be so off? I made sure to use all of the LME and I'm pretty sure my water volume was solid.

 

[JLem]

I missed a NB OG by about 5 pts -- thought i'd get my hands dirty with some troubleshooting. Any idea how a measured extract kit could be so off? I made sure to use all of the LME and I'm pretty sure my water volume was solid.

If it was an extract kit and your volumes were good, your OG isn't off, just your measurement of your OG. A couple of things may be going on:

1) your hydrometer may be off - check it in some tap water (corrected for temperature)

2) if you topped up with water after your boil, your wort wasn't completely mixed. It's tough to get a wort completely mixed when you add top-up water.

Personally, I wouldn't bother messing around with the beer, even if your OG is low by a few points (which I doubt it really is)