Mineral Taste in Dark Beers

[Gavagai]

I've noticed that some dark beers, such as Black Butte Porter, have a pronounced flinty, mineral finish. Anyone know what causes this?

 

[Cbaddad]

The ones you have brewed or those sold in the stores?

 

[Gavagai]

Commercial beers. I'm thinking specifically of Black Butte Porter and Anderson Valley Barney Flats.

 

[GinSlinger]

There are some yeasts that are known to produce minerally finishes. Windsor, for one, is known to. Some say they get it from PacMan. I tend to enjoy a little mineral and am fond of the almost oyster-shell hints I have in my last Windsor batch.

It also may be that the brewery's water has more minerals for their darker beers. Either they're not diluting down hard source water, or they're adding hardness to compensate for the mash pH effects of dark grains.

Is this flavour something you like or are trying to avoid?

 

[Gavagai]

I'm not really a fan of the flavor. I think you're probably right that it's coming from the yeast. I very much doubt anyone's adding hardness to dark beers, considering that would have the opposite of the desired effect. They might be adding alkalinity, but I don't think the quantity required would have such a dramatic flavor impact.

 

[GinSlinger]

Alkalinity = carbonate hardness. Waters with low residual alkalinity (carbonate hardness) may be unsuitable for beers with a large amount of dark malts.

 

[eriktlupus]

Quite a few of the historically dark beers are actually the result of a harder water profile and this is part of the correct flavor profile for them eg...guinness is one. Unfortuately 95% of the beermakers in the us have a natural hard water profile and must filter in some way. This includes those on municipal water system that filters it for them

 

[Gavagai]

Carbonates don't really have much flavor, though. It takes a LOT of chalk for me to be able to taste it, even in water.

Granted, the flavor could be something else in the water. But it's certainly not sulfate, since I've never tasted it in an IPA. Perhaps there is a level of chloride between 'enhancing malt sweetness' and 'nasty nasty saltiness' at which it produces flinty flavors.

 

[Teromous]

Many breweries do water adjustments, which sometimes results in noticeable mineral taste. Otherwise it could also be their unmodified water. I don't know about that brewery specifically.