Fixing/Masking diacetyl on a NZ Pils

[Crusader-Rob]

I'm not even sure if it is Diacetyl.
a NZ Pilsner using Riwaka and Motueka Hops with W34/70 yeast.(Dry)
I've been lagering for 2-3 weeks and theres a flavour there I'm picking up. The only thing I can think of is Diacetyl, so it's probably that.
Is there anyone who can tell me the best way to minimise the flavour contribution? I have a black IPa in for fermentation currently, so I could theoretically put the keg in the ferm fridge at 21 for a diacetyl rest? but after three weeks lagering will it remove it?
The other Idea I had was to dryhop the crap out of it, using the remaining 25g of motueka, along with a bunch of riwaka I have. i also have some spare Nelson Sauvin.

any suggestions?
W34/70 yeast was fermented at 13 degrees celsius. with a supposed D-Rest for 48 hours at 18 degrees. 

[Samuel Loader]

Hi Rob, 

have you used riwaka much before? I no longer use this hop as I find it gives a burn rubber taste to my beer. If it is Diacetyl (Butter, butter scotch, rancid butter flavour) then if you want to try save the beer I would try a repitch of yeast (use a liquid yeast and starter to get the yeast really active) re-ferment and D-rest. This is because your yeast are probably stuffed if they didnt suck up the Diacetyl in the first ferment and the new yeast will hopefully get the Diacetyl and also get any oxygen you reintroduce through this process. I dont think more hops will cover up the Diacetyl flavour as these are picked up on different areas of the tongue ( end up with hops rolled in butter)  

Hope this helps

[Mark Weusten]

ha ha burnt rubber. I find riwaka tastes like the smell of diesel at high amounts but I don't mind it so much. I'm not sure 34/70 and riwaka like each other that much. My riw/mot 34/70 pils at 40 ibu is still got a nasty initial bitterness, I think it would be better with noble hops. No diacetyl however, I would try a dry hop.

[Peter Smith]

I got burnt rubber off an underpitch of munich lager yeast....     same yeast was fine second brew when I used entire cake...

I have heard that you can repitch yeast AND add some more unfermented wort...   causes another ferm cycle and on this one warm it up with 20% left to go....       other wise put it in a carboy, add some bugs and leave it for a year or two....    bugs will clean it up