Low Attenutation

[redtangent]

Hey all, looking for a bit of advice.

DIPA, OG 1.070 Mash temp of 152, fermented at 68 for 5 days, then ramped up to 72 to finish seems to have stalled at 1.019 after 20ish days. I know that isn't necessarily enough time to tell for sure, but most of the fermentation happens in the first few days. I pitched a large 2 liter starter of Omega OYL-052, oxygenated with pure O2 and the fermentation started strong.

Should i just wait longer, or get another starter going and re-pitch to be safe and get to my 1.012-1.014 FG? Normally my beers are done fermenting by this point and I'd rack to keg or secondary to dry hop. Or do I accept the 1.019, which ends up at 72%, which is just at the low end for the yeast.

The only difference in my process is moving up to a 5 liter flask and making 2-3 liter starters, then saving 1 liter of it for a new batch. As far as I know that shouldn't be causing yeast growth issues.

Thanks,

-Steve

 

[kev211]

What was your recipe?

 

[D-Train]

I'd guess it's done. A lot of people, myself included, seem to have lower attenuation with Conan. 72% AA isn't that bad and is in the advertised range of your culture. A recent blog article I read says that Conan doesn't ferment maltotriose.

 

[Moose_MI]

What was your recipe?

^^^^^ this

 

[redtangent]

In case anyone is curious, it's basically an SOS clone, came out GREAT last time.

11 lbs Pale Ale Malt 2-Row (Briess) (3.5 SRM) Grain
3 lbs Vienna Malt (3.5 SRM) Grain
1 lbs Oats, Flaked (1.0 SRM) Grain
12.0 oz Carapils (Briess) (1.5 SRM) Grain
4.0 oz Caramunich I (Weyermann) (51.0 SRM) Grain
4.0 oz Carared (20.0 SRM) Grain
1.50 oz Columbus (Tomahawk) [14.10 %] - Boil 60.0 min Hop 7 74.3 IBUs
1.00 oz Citra [12.70 %] - Boil 20.0 min Hop 8 15.0 IBUs
1.10 Items Whirlfloc Tablet (Boil 15.0 mins) Fining 9 -
1 lbs Corn Sugar (Dextrose) [Boil for 10 min](0.0 SRM) Sugar 10 5.8 %
3.00 oz Citra [12.70 %] - Boil 5.0 min Hop 11 22.3 IBUs
3.00 oz Citra [12.70 %] - Steep/Whirlpool 30.0 min Hop 12 37.1 IBUs
1.0 pkg DIPA Ale (Omega #OYL-052) Yeast 13 -
1.10 tsp Yeast Nutrient (Primary 3.0 days) Other 14 -
1.50 oz Citra [12.70 %] - Dry Hop 10.0 Days Hop 15 0.0 IBUs
1.50 oz Citra [12.70 %] - Dry Hop 4.0 Days Hop 16 0.0 IBUs

This was my first time using the Conan yeast so I wasn't sure what to expect, sounds like its on to secondary and dry hopping! It does taste just fine from the samples, I'm probably chasing numbers too much at this point.

-Steve

 

[kev211]

How long did you mash? Cuz with that recipe and your given O.G. you were only at ~58% efficiency which is pretty low. That being said, I plugged the numbers into brewersfriend and got an expected F.G. of 1.018. So it sounds like its done. You're only 1 point off and based on what people have said, Conan yeast apparently is a lower attenuating yeast.

Another thing to think about is your mash temp. For me, I find 152 a little high for a double IPA. I usually mash my DIPA at around 148 to break down more of the beta amylase and get a more fermentable, and in the end, dryer beer. At 152 you're kind of in a gray area between alpha and beta amylase, but chances are you will end up breaking down more alpha amylase and have a more full bodied beer (which is totally fine!) but it will be less fermentable and end up with a higher FG.

 

[redtangent]

Efficiency is something I'm working, trying to find the variable to increase it, I had wondered about mashing lower than 152. Mash was just about an hour with a mashout at 168 at the end. I always thought 152 was in general a decent compromise between alpha and beta amylase, decent fermentability with a medium body. This is one of those things I'm still trying to master, and a good reason I like these forums, always more to learn.

Beersmith estimated the final gravity at 1.014 and overall efficiency at 63%, maybe its just a matter of using different software to get the FG target?

At this point I think i'll go ahead and transfer to secondary and start dry hopping. I have enough Citra hops for a few more batches so I'll try 148 or 150 next time (this is why taking notes helps).

Thanks for the help.

 

[kev211]

Efficiency is something I'm working, trying to find the variable to increase it, I had wondered about mashing lower than 152. Mash was just about an hour with a mashout at 168 at the end. I always thought 152 was in general a decent compromise between alpha and beta amylase, decent fermentability with a medium body. This is one of those things I'm still trying to master, and a good reason I like these forums, always more to learn.

Beersmith estimated the final gravity at 1.014 and overall efficiency at 63%, maybe its just a matter of using different software to get the FG target?

At this point I think i'll go ahead and transfer to secondary and start dry hopping. I have enough Citra hops for a few more batches so I'll try 148 or 150 next time (this is why taking notes helps).

Thanks for the help.

152 I think is a good middle area. Thats why its kind of a gray area. I just know that with my DIPA's I like to go lower towards 148.

It definitely could be the software. Like I said, I used brewers friend and got 1.018 FG so that could be it.

Whats your mashing technique? Do you stir during the mash? Or just dough in and leave it? Are you crushing your own grains?

 

[D-Train]

Are you entering your yeast into beersmith and also entering the published attenuation range in the yeast properties?

 

[redtangent]

I use a single tier HERMS setup and continuously recirculate the mash, basically the same as Kal's Electric Brewery. I'm a bit concerned about channeling being a cause of some of my low efficiency. The returned sweet wort into the MLT just come out a hose and floats on top of the grain bed by an inch or two. I do normally stir the mash a few times during a 45-60 min mash. I crush my own grains with a monster mill 2, set to .045" i think (would have to double check). According to Kal his setup gets 95% Mash efficiency and I'm getting something like 75%, not enough to cost me a lot of money per batch but I'd love nothing more then to fix that. I'd owe you more than a few beers if you could help me track down my issue.

 

[redtangent]

I do always enter the yeast into Beersmith and actually found an update for the program that included all the Omega yeasts. I'll double check what Beersmith has for stats vs the Omega site, didn't think of that before.

 

[m00ps]

1.019 is just gross for a DIPA in my tastes. Id add something else to take that FG down. If my DIPAs finish above 1.010 me no happy

2nd generation fo conan usually steps up its game