Diacetyl advice needed

[Craig]

I'm keen to get hear if any of you guys have ongoing issues with Diacetyl developing in the Keg. I have this ongoing issue once the Green beer hits the keg.

This following scenario is doing my F%&^$ head in, and I really need some advise, beyond yeast selection, sterilisation and diacetyl rests.

I recently brewed a bit of an Emersons Pilsner (Ale) Clone with NZ ADM Pils Malt and 5% Caramunich 1. To this I added 100% Riwaka hops in three additions. I also used 1469 - West Yorkshire Ale yeast.

Everything seemed perfect. Premo mash, boil and fermentation hitting every target bang on. Temp control was sweat - pitching at 18C, rising to 20C over the first 3 days. I also encouraged it to rise to 22C after a week for a wee rest. The Green beer tasted f'n fantastic straight from the fermenter. Real tropical with passionfruit aroma and taste.

After a total week and a half ferment I slowly dropped it ~4C a day till I hit 1C where it sat for a few days. Then kegged it (no finings). At this point it was still fantastic and a little less yeasty. Still a bit hazy though. I then hooked up CO2 at normal despensing pressure.

Week later couldn't resist a taste. It still tasted good, but aroma seemed to be fading. It appeared to be losing its tropicalness... (I put this down to tempurature initially.)

Another week later and I couldn't smell a thing, but caramel sweatness. And the tropical, hop character was dead in the taste also. I'm a little numb to the whole Diacetyl thing but I think that is the problem masking my once great beer. The beer doesn't otherwise seem problematic.

How can this issue be developing so badly in the keg once on tap. Has anyone else had this problem? Am I not cleaning my lines enough? Should I be dismantling my kegs every time I clean them? Is my vibrating chiller having an adverse effect on the remaining yeast? Am I just going F'n nuts?

Should I try bottling some as an experimental control group...?

[denimglen]

Have a look at this

There's a test there that you can do to see if there's much diacetyl precursor left.

Also I would have let it set for at least two weeks, more likely three, before crashing it out, but I don't know that yeast well.

[Craig]

That is a great article. Got two new things to try out... Not sure what shyt watery beer to buy though for training/confirming my Diacetyl tasting skills...

I hope like hell I don't have to come back and say sorry I stated the wrong issue...

Cheers
Craig

[JoKing]

I'd like to know if you've had these issues with 1056 / us-05... or any other strains for that matter.

What I can tell you about 1469 is that it is know to produce diacetyl, however 3 days at 22 post fermentation (POST fermentation: meaning you MUST have met terminal gravity before forcing the yeast to scavenge) really should have taken care of any diacetyl... unless there was an underpitching problem, an infetion or aeration / oxygenation problem... which I doubt - as you seem quite festideous. However... a quick question: what was your SG, and did you make a starter for this batch?

Here is some more releiving information about 1469. I made a 1.058 Ale with 100g of cascade at the end of the boil, and found the exact same trend that you speak of here. It took 2 full months at zero to condition, and only after kegging, the hop character was all but gone. I put it down to being a typical English strain eating the hell out of the hop characters ala 1968.

Hope that helps.

[Mike Neilson]

I dont know what the big deal with 1469 theres a reason why its a PC strain, it's because its shit!! a English yeast that dosnt floc? what up with that!!

[Stu McKinlay]

I liked it. Was great in Kid Choc (and I assume it is the same yeast Galbraith's use - love their beers).

[JoKing]

I think it is what makes Landlord so good. It can be a difficult strain to work with and when you get it right - the results speak for them self. But if you get it wrong, it can be very much unforgiving.

[Stu McKinlay]

Like 1968 (Fuller's).
I guess the greatest beers are made with the greatest yeasts, eh?

[JoKing]

Exactly. I wonder what they use at Russian River? I've heard that it is 1056... but I could be wrong.

Green Flash use 001 - and West Coast IPA is my favourite.

Fuck I can't wait until the 17th...

[Greig McGill]

I've had nothing but great beer with it. That's why I scavenged some recently (thanks again Reviled and studio1), as I just love the balance you get with it. It leaves the malt and the hops well alone, while imparting a beautiful stone fruit character that I just can't get enough of. I've not had much in the way of diacetyl issues with it, but then I always finish with a warmer rest for ales anyway, always have.

My oatmeal stout is using it right now. It's going gangbusters.

[Reviled]

Wash your mouth out Mike, 1469 is like, my house yeast ;o) I love it and havnt got any diacetyl off of it myself...

I used to think I wasnt very sensitive to diacetyl as well Craig, but then I was handed a 'worthers original' beer in aussie and was like "Ahh, so thats what diacetyl is" It was literally butterscotch jumping out of the glass and made it quite unbearable... I think it was brewed with Ringwood?

[Mike Neilson]

This was the exact response I was waiting for hahahahaha!!!!!!!!!!

[Soren]

During fermentation the yeast produces a flavorless precursor that is excereted out of the cell. In solution it will eventually be converted to diacetyl, which stinks. The diacetyl is then transferred back into the cell and broken down to neutral compounds. Thats why its important to have a diacetyl rest, with the yeast still in suspension, otherwise the diacetyl formed from the precursor is not removed. I have never tried 1469 but I think it can take weeks for some strains to degrade the diacetyl, so try a longer rest... Also, the higher the pithjing rate the faster the reduction of diacetyl as well, so you could try pitching more yeast, don't overdo it though:)
Oh, I think I've heard that aeration of the mash/sweet wort can create compound with similar flavor to diacetyl, so be carefull spalshing around there too.
It could also be keg/line sanitation, as bacteria can produce diacetyl, but normal homebrewing pratice should take care of that.