Beginner diacetyl issues. HELP!!!!

[NordeastBrewer77]

I've been brewing using mainly American yeast strains for 6 months now with pretty, sometimes very good results. So I decided to brew a couple English bitters, one using wyeast 1098 brittish ale (1 activator pack) and the other with Wyeast 1968 London ESB (2 activator packs) I read up on diacetyl, diacetyl rest, rousing sluggish yeast, etc.
With both beers, after fermentation ceased, I allowed the beer to rest for a few days before transferring to secondary for two weeks. Both are finished, bottled and ready to drink, and both taste like butterscotch.
Is this a result of underpitching or was my approach to diacetyl rest way off? Or could it be something else?
Please help cuz I love British isles pale ale and paying $10 for 4 nitro cans when I have 3 carboys is a painful thought that I revisit a few times a week!

 

[SD-SLIM]

Hello...this is usually due to long lag times (caused by week yeast) or by insufficient aeration...here is a link to John Palmers book and in particular off flavors: http://www.howtobrew.com/section4/chapter21-2.html

 

[NordeastBrewer77]

Actually, both batches kicked off fairly quickly. I always aerate thoroughly and paid extra attention with these two because I read that both strains were lazy and like to fall out early

 

[dancness]

What was your OG? You said the beer was in the secondary for 2 weeks. How many days did you have it in the primary, and what was the fermentation temperature?

 

[NordeastBrewer77]

OG-1.06 EG-1.018
primary for ten days, seconday for 19
That was the beer using 2 packs of wyeast 1968

 

[dancness]

For a 1.06 OG beer, I'd leave it in the primary a little longer to allow time for the yeast to clean up after themselves. You didn't mention the temp, but if it is in the high range (above 75F or so) this could be another cause of the butterscotch flavors.

It appears that you pitched plenty of yeast. In fact, 2 packs may have been more than you needed for a 1.06 OG beer. However, I don't think that you overpitched so that's probably not the reason for the butterscotch flavors.

My opinion is that a lot of diacetyl was produced early on in the fermentation, and the yeast were not given enough time to clean all of them up since you racked off the yeast cake after only 10 days.

Just give your beers some time in the bottle and hopefully those butterscotch flavors will reduce.

 

[doctorRobert]

What temp did you pitch the yeast at? And what temp was fermentation at?

If you pitched the yeast too hot, that could be why. Best to pitch yeast at below fermentation temps.

 

[NordeastBrewer77]

I pitched at 68, room temp. Once the yeast kicked, my stick on read 72. Dropped back to 68 when the kruesen fell. I let it sit in primary at 68 for four days after active fermentation was unnoticeable. But I think I should have left it longer.
Is there any use in rousing flocculated yeast during a diacetyl rest? I didn't because I was worried about the beer oxidizing.
I don't think it's a sanitary issue... I have a pretty good regimine and only these 2 beers have that taste

 

[ayoungrad]

72 is arguably close to too high. But are you sure it's butterscotch? You are going to get fruity esters with british ale yeasts.

 

[ayoungrad]

According to WYeast, they also reccommend a diacetyl rest which is done before primary is done, not after as it seems you did.

 

[giligson]

According to WYeast, they also reccommend a diacetyl rest which is done before primary is done, not after as it seems you did.

Sorry?
BEFORE Primary?

Was this an extract brew - how old was the extract?

 

[ayoungrad]

Sorry?
BEFORE Primary?

Not BEFORE primary but, as I said, before primary is done (before it is complete). A diacetyl rest is a product of the yeast. Once yeast flocculates (after primary fermentation is done), the effectiveness of a diacetyl rest plummets.

 

[giligson]

ahh... sorry missed the "is done" part.

 

[NordeastBrewer77]

72 is arguably close to too high. But are you sure it's butterscotch? You are going to get fruity esters with british ale yeasts.

I'm pretty sure its not esters, those are fruity. Diacetyl is buttery/butterscotch and gives a slick mouthfeel. Not to mention the beer also has fruity esters as it fermented at 72. My issue is with diacetyl.

What I read about a diacetyl rest was that you leave the beer in primary at or slightly above fermentation temp for several days before racking it off the yeast cake. Is what I read wrong? If so, what should I do to get the yeasty guys to clean up their buttery mess?

 

[SD-SLIM]

Did you pitch your yeast while the wort was warm and then slowly bring the temperature down?

 

[ayoungrad]

Usually you raise the temp a little (5-10 degrees) during the end phase of primary (before the SG hits FG). You know when to do it by watching the fermentation intensity and taking gravity measurements. So what you read is correct but it sounds like their wording places the timing and temperature for the diacetyl rest in the realm of guesswork.

 

[NordeastBrewer77]

Cool, thanks man.... I think that's what I read, I just need to make sure I warm the beer up before it finishes fermenting, not when it does. I appreciate the more specific info man, thanks