stouts

The last time I tried brewing a stout via the AG method, my efficiency sucked--actually needed 3# of DME to make it up--and my color was off. I love stouts but am afraid to brew another AG stout. On that note, after the money I've spent on the barley crusher, the burner, the big stainless pot, etc, SWMBO would kill me if she caught me doing an extract batch anytime soon.

I don't get it. This issue should be across the board if it's a beginners extraction problem. The efficiency of pale ales I've done, including the one last night, have been right on target--all target gravities met. In fact I was 0.006 higher that target on the pale ale last night...

So, is there some trick to doing a stout that I might be missing?

No tricks that I'm aware of, a stout is like any other beer. The only thing that may come to mind is if you made a dry stout with a high percentage of flaked barley or an oatmeal stout with a high percentage of oats. Either could cause you some lautering problems. You could try adding a couple handfuls of rice hulls to help out.

What was the recipe?
My first partial mash oatmeal stout had a lot of issues mainly low eff due to a stuck sparge.
When eff was low, what type of DME did you use (extralight vs amber)?
I usually keep a few pounds of both light DME and amber DME on hand to add to low eff recipes, u ise the light for pales and the amber for porters and stouts.

No real difference with stouts vs Pale ales unless you are using flaked barley or oats. A significant amount of flaked grains can make lautering difficult and can take longer to convert than beers made with mostly malt.

Also if you have very soft water then the ph of the mash can drop below ideal for the mash. Some cheap ph strips can let you know if you are in the correct range. You should be around 5.2 ph. Roasted grains are more acidic than pale grain and soft water has less buffering allowing the ph to drop significantly. If you have hard water or use a 5.2 buffer then this should not be an issue.

Craig

When I did my first all grain batch (a porter), it didn't occur to me that you put your specialty malts in your mash tun instead of steeping them in a grain bag pre-boil. That beer didn't turn out well and the color was way off (i.e. more red than black). Unless you're making the same bone-headed mistake I did, I'm not really sure what the problem is.

Oh, wait... Large amounts of dark malts lower your mash pH. So it's possible that your mash pH is throwing your efficiency off. Since you're a chemist too, I'm sure you could devise an experiment to see if this is a factor.

EDIT: On a possibly related note, I just did a porter which had lower efficiency than I was expecting (71% versus my 80% running mean). But I think this might be the result of brewing at a substantially higher gravity (1.074 versus 1.050) than normal.