Bad efficiency, low SG , top-up with additional wort?

I brewed an Galaxy/Pacifica IPA last night and ended up with 55% efficiency (BIAB) and this 80 IBU will only come in at an estimated 5.2%. I've did enough reading on this after the brew and it could have also been a miscalculation on my part, either way I will be troubleshooting this later.

Could I top this up with additional wort if I did a quick 15 min stove top boil with light DME? I've yet to pitch as I forgot to make a starter before brewing. It's currently sitting in my ferm chamber at 64f and plan on pitching tonight. I could rack it off the trub to free up some space.

If so is there a calculation so I could get back to the 6.5% ABV I wanted?

 

It's easy to calculate how much DME you would need for your current volume, the problem I think will be getting it to dissolve in a small amount of water. Do you have the target OG, current OG, and current volume? For a 5 gal batch you'd probably need a bit more than a lb of DME added to the current volume to hit your target, but the more water you add the more DME you would need.

 

OG is 1.050 and I'd like to get this up to 1.060.

I got a lot of hop trub in this brew so if I racked it off into another car boy I could easily add a couple more liters of water/wort.

 

I assume you have 5 gal? Then you need 10pts x 5 = 50 more gravity pts for your current volume, or about 1.1 lb DME. But for every gallon of water you add you need another 60 pts, or 1.5 lb DME. In other words you would need to dissolve 2.6 lbs DME in an extra gallon total volume and add that. If you try to do it in a half gallon you'd need 1.1 lb plus the .75 lb for the new water, or 1.85 lbs. I don't work with DME too much so not sure how easy that would be in that volume.

 

Thanks for the info, I'll need to read this over a few times to make sense of it - and yes I have 5 gallons. I'd like to try this using the least amount of water as possible as I don't want to reduce my hop bitterness, flavor and aroma.

 

Actually slight correction, that would be 1.33 pounds DME for every gallon added. So add that to the 1.1. Sorry I was on my phone doing calculations in my head.

 

Yeah that's the downside, messing up the rest of the recipe. In your shoes I'd probably just let it ride at this point. Next time take the gravity before chilling and you could add your DME then.

 

I could do a 20 minute boil with the DME and throw in some of my dry hop..?

I'll think about doing this tonight but I'll probably keep it the way it is - session IPA.