I'm having the same issues with attenuation in my Oktoberfest, but with a different yeast strain. I opted to use Wyeast 2633 - Octoberfest Lager Blend.
According to Wyeast, their Oktoberfest strain is a "a blend of lager strains designed to produce a rich, malty, complex and full bodied Octoberfest style beer. Attenuates well while still leaving plenty of malt character and mouthfeel. Low in sulfur production."
Unfortunately, after 3 weeks in primary (2 at 50 degrees F and 1 at 60 degrees F), I'm at 69% attenuation. The yeast's purported attenuation range is between 73-77%.
Has anyone had any similar issues with this yeast? I'm not sure of the source. If anyone has info, please post.
As far as fermentablity of the wort, I did a triple decoction, so I don't think that it's an issue (see the brewing log
for the recipe)
Based on what I've read in this thread and from other sources, I have some options:
- Gently swirl the carboy to get yeast back in suspension and wait it out.
- Ramp up the temperature to 65 degrees F to get the yeasties to consume the last of the sugars, swirl, and wait it out
- Take a sample and do a "forced fermentation" to see if the are, indeed, any fermentable sugars left.
- Add a fresh inoculation of an attenuative yeast like US-05 or WLP001, swirl, and wait it out.
- Rack to a secondary to see if any further fermentation will occur. If not, cut my losses.