Well, lets recap.
for a good fermentation yeast needs the following:
- good pitching rate of healthy active yeast (should be taken care of with using a starter)
- sufficient O2 (this might be a problem, but you said that you underaerated violent fermentations before)
- freely avaibale nitrogen (FAN) (this comes from the malt. Mashes high in adjuncts can have a deficiency here. But if you use good pale malt, you should get more than enough for your yeast even w/o making a protein rest)
- trace minerals, Zn in particular is necesary for a good fermentation. (But an all malt mash should supply enough)
- fermentable sugars (There should always be enough in the wort to get a good fermentation if you had conversion).
Since you seem to get good fermentations with extract, I suspect problems in the recipie/mashing of your beer.
To pinpoint the problem, try the follwing:
- Make an all barley malt (pale malt, as this is well modified) AG ale
- add some yeast nutrient to the boil. I'm not a big fan or doing this, but it might help finding the problem.
- pitch a 2 qt starer at high Kraeusen
- aerate sufficiently (20 - 30 min with air or 1-2 min with O2) at a wort temp below ~75F
If you now get a violent fermentation, it must have been a yeast nutrient defficiency in the mash. This is pretty unlikely with all malt mashes, but I can't think of anything else right now.
Kai