Am I expecting too much attenuation from my lager yeast?

So--I have an American Lager brewing with Wyeast 2035 American Lager. I was shooting for near 80% attenuation. I have gotten 80-85% before with US-05. I am now at 76% after fermentation has stopped and the D-rest is done.

My recipe is here: Hopville . "American Lager" Premium American Lager Recipe

I used 9% of total grist as flaked rice, mashed at 147 degrees, and pitched a massive 5 liter starter from a stir plate. I gave it 1 minute of pure O2 and then 30 seconds of O2 after 6 hours. 76% is right in the range they give for the strain, but I was expecting more given the starter size, low mash temp, and rice. Any input? I really wanted a dry lager (above 80% AA).

With a big enough starter (or 4 packages of yeast without a starter) you can reliably get 75-78% attenuation of this yeast (80% is rather unlikely) for a FG of 1.010- 1.012.

76% is about right for the yeast strain you used.

Mash at 143 for 3 hours next time (assuming about a degreeof cooling per hour.) I don't feel like writing a paper in this post but there are two main enzymes that convert starch into sugar, alpha and beta amylase.

One will break off the ends randomly and the other will basically break them in half. By mashing at the low end of the spectrum you accelerate the major breakdown and by doing it so long you let the random one work veru very slowly randomly breaking any remaining larger chains left. The result is a wort that will be very extremely fermentable.

That's how Budweiser does it for theirs (they may even go 4 hours I don't recall)

Thanks a lot for the input. I did 147 degrees for 30 minutes and then 151 degrees for 60 minutes with a fairly watery mash (over 1.5qt/lb). I guess I could go cooler for longer. I think it'll taste great. It is my first lager with a stir plate and I think it'll make all the difference.