Any way to adjust IBUs after brewed

I just finished brew an Imperial Irish Stout witch recipe had a mix of dry and liquid malt extract by Muntons. I calculated what the IBUs should be using Beer Smith and I made an error.

The Muntons Dark liquid extract I have was hopped and I entered in the program unhopped.
I wanted it to come out 45-50 IBUs but I re -did the calculations and I thinks its in the 70s. I’m not a hop head I didnt’ want it to be that bitter. Its in the fermentor right now. I tried some when I read the OG which was 1.07 like I wanted, but I couldn’t even finish it was to bitter.

Is there anything i can do to lower IBUs once its in the fermentor? I was going to add Cacao in the secoondary so that ought to sweeten it up a bit.Can I just diute and add more water to fermentor?
Any other tricks. I know it will smooth out over time but its just too bitter.THANKS.

Not really. It will smooth out over time and the freshness of the hops will fade a little which may make it better. Adding water is going to dilute the whole beer so you would lose body, flavor, alcohol content and IBUs. I wouldn’t recommend that unless a watered-down version of this beer sounds more in line with your tastebuds. All homebrewers make rookie mistakes (Are you a rookie? I don’t mean that to sound condescending) and you learn from it. One other thought is to make another version of this beer and underhop it and then blend the two beers together. Do the math to figure out how low to go on the second beer so the two beers come out around your original target. This is something commercial breweries do to get better consistency. Good luck & cheers.

Yeah, blending is about the only thing you can do. I would leave it alone and see what you think first though. And adding cocoa isn’t going to make it any sweeter, pure chocolate is bitter not sweet. If you did add something sweetened (which I don’t recommend) the sugar would just ferment out.

Are you basing the bitterness off of a taste before fermentation happened? I find wort before ffermentation tastes horribly bitter even for a beer with low ibus. If you have extra extract, specialty grains, and head space in fermenter i suppose you could brew a scaled batch with no hops to dilute the ibus to where you want them. But that’d be lot of work and I bet the beer turns out way better than you think by doing nothing.