Need help fixing a beer with very low FG

[JonAllenNH]

Hey guys - It finally happened...I finally brewed a BAD batch of beer.
Tried to squeeze in a brew day with the kids running around and not enough time. Also tried a BIAB 'sparge' method that was completely unsuccessful. I forgot to take a pre-boil gravity reading and the OG post-boil was WAY low (shooting for 1.052 and it was 1.040). Decided to ride with it and see what happens. It's been fermenting for about 5 days, activity has stopped and it finished at >1.010. Tastes like hop flavored water...yuck. Rather than pouring it down the drain I was going to try to fix it and wanted to see if there were any ideas out there.
My thought is making a .5 gallon DME batch (like a yeast starter) of wort, with the left over hops, that has a 1.200 OG and adding it. In THEORY it should blend with the 5.25 gallons in the fermentor and up the cumulative OG to 1.050 and hopefully up the residual sugars and FG up a few points to give it some flavor and body. Obviously not ideal and I'm going back to my normal methods where I have an 80% efficiency. I intend to make this recipe again regardless, but I'm hoping I can do something to make it at least drinkable/enjoyable so it's not a complete waste of money and time... I know it'll F with the hop profile and the flavor won't be right by doing this, but...better than nothing and at least I can experiment with it...any other ideas?

 

[hercher]

I think you have the right idea, but rather than just doing a DME batch, why not make another beer and blend it? You indicate your beer finished above 1.010, so you might want something that will finish relatively dry.

 

[JonAllenNH]

You indicate your beer finished above 1.010, so you might want something that will finish relatively dry.

Ha, my bad, it's less than 1.010 not greater than. I decided to do a little bit of all of the above. I'm still going to do a .5 gallon batch that's DME, but I'm going to hop it to try to save the hop profile. I'm essentially making a really small super high OG version of the same beer. Keeping IBUs and SRM about the same. I also double checked my math, looks like I only need 1.168 not 1.200. Should make the combined OG 1.051 and the combined 1.013 based on the estimated attenuation per the 'recipe'...if you can call it that when it's just extra light DME, amber DME and hops. Hoping this works and at least results in a drinkable pleasant beer. Since the yeast are still active from the initial fermentation and have grown to large numbers now I'm expecting a pretty explosive fermentation once I add the new batch. Hopefully it doesn't blow the airlock and stopper...going to start off with a blow off tube on the air lock for a few days and hope for the best. It'll be 5.75 gallons in a 6 gallon carboy...asking for trouble.