all grain said:
most say not to use softened water because of the salt but I add a some salt when I brew with ro water and I don't think that's your problem. its a guess but I think you are probably tasting off flavors from the yeast. keep your fermentation temps lower. in ale try to keep the temps 62-66. I use to get off flavors at 70 and most say 70 is to high. If you rush the fermentation there also will be off flavors. myself for ales I do 2 weeks primary 2 weeks in the bottle. when I sample some early there not as good.
as far as the grain bed goes, not sure what your set up is? do you batch Sprage or fly? if you get stuck Sprage you can add rice hulls next time. also keep the temp up at 170, the wert will flow better. some of my Sprage take 30 min and they are just a trickle. you may need a different screen. need more info.
. PS I have never used softened water so I don't know. I would buy spring water at the store.
Water softeners replace the mineral ions with Sodium ions, at approximately 120% of the ppm replaced. So, if you have 100ppm of minerals in your source water, your softened tap water will have 120 ppm of Sodium. the maximum recommended sodium content for a beer is around 150 ppm. So, your mineral hardness would need to be below 125 ppm total. That's not really very "hard" water, and some water can easily have 200ppm or greater of mineral content. So, sodium levels can easily be well over 200 ppm coming out of the softener. Therefore, the use of softened water should be avoided, unless you have actual data showing your sodium content is acceptable.
Fermentation temps certainly make a big difference. But, 62-66 is a bit low for a general Ale recommendation, if you are quoting the BEER temp. But, it would be about right for the AIR temperature. The recommended Beer fermentation temp for most ales is closer to the 68F mark (with the air being 2-4 degrees colder during ACTIVE fermentation). This varies a LOT with yeast strain, though. So, such a generic recommendation must make a lot of assumptions. Robin doesn't say what his fermentation temperature actually is. Low 70s or below and I doubt he'd know the difference. Besides, he hasn't even said ale vs. lager. So, really the range is wide open.
Robin: You don't say what type of off flavor you are tasting. This might help to narrow down the cause. Can you describe what you are tasting? Does it taste like:
stone fruit (peaches, pears, apricots, cherries),
green apples,
sharp and bitter,
buttery,
salty,
chalky,
astringent (like over-steeped tea...makes your mouth feel dry),
just taste like a$$ (aka nasty, undrinkable stuff),
band-aide/plastic
Sour
Vinegary
meaty
Do you see anything floating around in the beer? White scum in the neck of the bottle, etc?
Does the beer have any kind of smell to it?
Since you say that the off flavors only occur with all-grain brews, I'd probably lean towards a mash or sparge related problem. You have hard water and are making lighter beers...this is often NOT a good combination. But, before going too far down that road...tell us what it tastes like.
I've tried to cover most of the possibilities, above. Some are the result of fermentation issues, or sanitation issues, or water issues, or mash conditions, or boil related, or process problems.
Perhaps you can give us the recipe of one of the beers that exhibits the referenced flavors? That way we can be a little more concrete and less abstract.