Thoughts on Diacetyl Rest time, temp for Imperial A09 "Pub" yeast

[Nate R]

Hello All.
Was hoping to pick some of your brains on this yeast. It is my first time using it and I have read it certainly requires a proper Diacetyl Rest.

Ale
A09 Pub Yeast pitched 11/30 (Sat) 10:30pm
Temp: 65f
OG: 1.064

Current Gravity: 1.017 12/4 (Wed) 11:30am.
So it has been fermenting for 3.5 days.
I read this strain is a fairly fast strain.

I was hoping to get some thoughts on:
When to start raising temps for Diacety Rest
What temp to go to? Should I do step(s) and raise in increments?
How long to keep temps higher for the Rest?

This yeast stats from Imperial are:
TEMP: 64–70F (18–21C)
FLOCCULATION: VERY HIGH
ATTENUATION: 69–74%
ALCOHOL TOLERANCE: 10%

I have a conical with temp control.

Thank you all!

 

[bierhaus15]

I brewed two beers with the same yeast recently, Fullers ESB and Porter clone. That said, the yeast performed very well and the resulting beers are clean and fermented to target FG. Both beers were pitched at 62F at 0.75 m/c/ml/P and oxygenated to 12 ppm. Gravity went from 1.057 to 1.010 and 1.054 to 1.012, for the respective beers, total fermentation time was about 4 days for each. Pitched at 62F and let free rise to 68F and held there for 6 more days (I was out of town) before kegging. No discernible diacetyl or other off flavors. The yeast is really nice, much better attenuation and fermentation than WY1968/WLP002, IMO.

 

[jekeane]

I would let it rise up to 68-70 now. The strain drops like a rock so you'll want to get your rest in before it flocculates out. Underpitching and not enough o2 with this train are where problems arise.

 

[Nate R]

I would let it rise up to 68-70 now. The strain drops like a rock so you'll want to get your rest in before it flocculates out. Underpitching and not enough o2 with this train are where problems arise.

Thanks. I am adjusting the temp up now.
Tye reason i picked this yeast is it was dated 11/18, so very fresh. I hope the cell count is good (no starter) and i did hit it with plenty of oxygen. This baby took off fast- it bubbled like a hefe strain!
Thanks!

 

[Vale71]

There is no such thing as a "proper diacetyl rest" for an ale fermentation. Barring serious issues with the yeast at ale fermentation temp diacetyl cleanup happens concurrently with diacetyl production and any diacetyl precursors will have been cleaned up by the time you start conditioning your beer.

 

[jekeane]

There is no such thing as a "proper diacetyl rest" for an ale fermentation. Barring serious issues with the yeast at ale fermentation temp diacetyl cleanup happens concurrently with diacetyl production and any diacetyl precursors will have been cleaned up by the time you start conditioning your beer.

I'm interested in what you think this means from the yeast manufacturer "Be sure to give beers made with Pub a sufficient diacetyl rest"

This is from White labs diacetyl timeline study "For ale production, the fermentation temperature is usually 65-70F, so temperature modification is not necessary. But the fermentation should still be "rested" at this temperature for two days to ensure proper diacetyl reduction."

 

[Johst12]

Even in ales diacethyl can be a problem in some cases. When a yeast is highly flocculant, the wort has a deficit in FAN and the beer is cold crashed or filtered too early, there might be not enough yeast in solution to work diacethyl to Burandiol (idk if thats the right english term). I guess thats what the manufacturer means and I guess it's a rare case.

 

[Nate R]

Wanted to update on this in case anyone else is considering this yeast.
After a Diacetyl rest, I dumped yeast. This stuff is SUPER floccuent!
I added an ounce of dry-hops after pitch, removed blow-off tube, and attached a gas manifold/prv cap.
I was expecting a few more points of gravity (in the form of a bit of c02) but I have gotten almost nothing.
It does indeed "drop like a rock"
Can't wait to see final product, will update.

Thanks again all for the feedback!