Oxygen aeration system???

Hey all Happy New Year, used my Oxygen system for the first time last wednesday, made a starter and aerated with O2 for about 1 minute, british white labs with a march exp date, first racking 6 days and the gravity was 1.023. way too high. Attenuation about 50 %. First time I've ever been that high,and I have never had the FG change from first racking to bottling, so what gives, any ideas?? Also should I pitch some dry yeast in there? FG should be about 1.014 its a stout, which tastes great but a bit heavy and only 3.3 % Alcohol

Need more details on your recipe and what you did with it to determine if you had a stuck ferment. Did you rack after 6 days based on timing or did the SG stabilize for 3 days?

I Racked @ 6 days because of very little activity which is the norm for me, 5-8 days depending on airlock activity, I never take readings 3 days straight because I don't like to mess with it. 50 + batches and never a problem. I used
7.20 lb Pale Malt, Maris Otter (3.0 SRM) Grain 0.85 lb Caramel/Crystal Malt - 60L (60.0 SRM) Grain 0.85 lb Chocolate Malt (450.0 SRM) Grain 0.29 lb Barley, Flaked (1.7 SRM) Grain 0.28 lb Roasted Barley (300.0 SRM) r

I thought it kind of odd that with a starter and O2 aeration that 6 gallons didn't need a blowoff, when I pitch a starter it always needs a blowoff.

Is it done fermenting? Also, your recipe is <80% fermentable so I would expect an FG much higher than 1.014. How did you arrive at that figure?

Well I thougt it was done, I have gotten lazy and never took a gravity reading before racking because when the bubbles stop its always done. A starter and O2 aeration and its the first batch in 50+ that died out. 68 degrees is where it sat. My OG was 1.048 and Beersmith estimated FG should be 1.014, about 70 % attenuation which is average for British ale yeast. So 1.023 is surely too high.
I used the 02 airstone for about 1 minute in my chilled wort, its the only thing I've done differently in a long time, should I pitch more yeast or just leave it? Thanks guys.

bandt9299 said:

My OG was 1.048 and Beersmith estimated FG should be 1.014, about 70 % attenuation which is average for British ale yeast. So 1.023 is surely too high.

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Beersmith and other programs I'm familiar with don't take into account that certain malts are for the most part unfermentable (crystals, roasted malts for example). It only uses the OG and the attenuation of the yeast which doesn't yield an accurate FG calculation.

Take out the crystal, chocolate, and roasted barley from your recipe and you probably have an OG in the upper 30's. Figure your 70-75% attenuation getting you down in the 1012-1014 range which is ~25 SG points. 1048 - 25 = 1023.

Seems to me your FG is exactly where it should be.

Baron, I'm not really understanding what you mean, if the fermentable OG was say 1.038 than 70% attenuation would be less than the estimated 1.014 not more. You lost me here, sorry.

I have brewed oatmeal stouts and porters with alot of the same ingredients and always came very close to my target FG. Never 10 points high.

bandt9299 said:

Baron, I'm not really understanding what you mean, if the fermentable OG was say 1.038 than 70% attenuation would be less than the estimated 1.014 not more. You lost me here, sorry.

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Now add in the ingredients I took out: roasted barley, chocolate, and crystal malts. They will raise the FG from 1.014 to something higher, such as 1.023. Those malts aren't fermentable (or barely so) and it wouldn't matter if your yeast had 100% attenuation.

Your mash temp can also be a factor...higher mash temps contribute more unfermentable sugars (which equal a higher FG), while lower mash temps create a more fermentable wort (which equals a lower FG). But you aren't going to ferment ~20% of the grist you listed (at least not with ale yeast) regardless.

If you want a dry stout then limit the unfermentables to 10% or less and mash low, around 150F.

I have not yet used an O2 system, but 1 minute seems like not nearly enough O2 to me. Did you do any other aeration, like shaking or stirring?

I usually siphon from brew pot to primary and let it splash around alot, then whip it with my spoon, but this time I did none of that, just about 1 minute of O2 as per williams instructions.