Help! Need to increase bitterness on kegged beer

I kegged a kolsch about 3 weeks ago that was supposed to be around 24 IBUs (.75oz of German Perle for 21 IBUs and .5oz Czech Saaz for 4 IBUs). Right after I kegged the beer I noticed that I only used .25oz of Perle, which equates to around 11 total IBUs. I have since used the remaining .75oz of Perle for another batch, however, I have plenty of other hops available.

What would be the best way to make up for the missing 13ish IBUs?

Hop tea.

Cheers!

day_trippr said:

Hop tea.

Cheers!

Click to expand...

So boil the hops in water? Do I calculate the IBUs as if calculating for a 5 gallon batch?

I've only ever done it once myself (and it did save a wheat beer for the spousal unit that I had gone way too wimpy with the bittering hops). I boiled up an ounce of known IBU hops that would have brought a full boil up 20 IBUs and added it to the keg. I'm sure the potency was a lot lower than would be achieved in an actual full boil, but it did the job anyway...

Cheers!