Help me save my beer!

I did a bad thing.. I did not vorlauf and now I have a stout with a bitter / astringent aftertaste.

Thanks to searching this forum I was able to figure out where this off flavor came from. However there weren't many suggestions how to salvage a beer with this flaw.

My stout is in my keg and I am willing to get avant-garde with it. Any thoughts of ingredients that could mask the astringency?

Time. I had a stout that had the same issue. The yeast will continue to do it's job and cut out most of the astringency. You could, however, soak bourbon in oak cubes or cocoa nibs and add the bourbon to the keg and carbonate. That would add an additional flavor without too much work.

I'd just wait. Most of the highly bitter particles will settle out over time. Unless, of course, this is already 6+ months old, and it's still extra bitter. Then you might be in trouble, and have to do something crazy like add a sweetener to balance out the flavors.

A quick google search and I found a similar question, but about the astringency in dark greens for someone making smoothies.(http://cooking.stackexchange.com/questions/25874/what-counters-astringency)

As per that link:

Many leafy and dark green vegetables have high tannic and dicarboxylic (including oxalic) acid levels. Though these are weak acids, they have a powerful astringent effect. Some of the main tricks to hiding and/or removing these are soaking in:

Ascorbic acid (vitamin C, lemon juice)
Fats
Food grade lime
Milk
So if your smoothy is milk based you will be extracting the maximum tannin from the spinach

A pre-soak in a small quantity of milk and then discarding that milk, or a pre-soak in lemon juice and then a quick fresh water rinse are probably the simplest "fixes" of the spinach's astringent effect

Thanks for the replys! This was a late March brew, so I am losing hope that time will fix it.

I will start the experimenting...Maybe some oak, bourbon and lactose for a barrel aged milk stout kind of flavor. Appreciate the input!