Dark Grains, Soft water and off flavors

[BucketHead]

Hello.. question about me using dark grains and soft water.
I have made several Stouts and Porters. I do add salts to my water for mash Calcium, etc.... all my goldens and ambers do very well.
My stout beers do well also, they are clear (although dark, I can see when I pour they are clear, transparent other than being very dark... 36 ot 44 SRM)... they tast very nice for the first month.... then they develop a slight to strong sour/acrid taste. I have been trying to determine why. First I thought I must have some bacterias or foreign material acivities due to not being able to clean the sanke kegs well enough. With time, I've eliminated that as the possible cause. I have bottled the last several batches. I notice that my last RIS, from bottles, has the same taste, although not strong enough to dump them.
This sour/acrid taste only comes from my dark beers. I then considered that one of my malts must have gotten damp or moisture in it and caused sourness to develop. I can't seem to get past this although I thought because I bottled, it would not happen.

my question then is... for someone who really knows water chemistry effects.... Is it possible that because I don't increase the hardness of my water with any salts.. ( I don't have access to Lime) ....would this be giving me the flavors I am experiencing when I all grain brew 'dark' beers?

In my last Stout, which is still in the fermenter, so I don't know how it will finish out after a month or more after bottling/kegging... I did use some Bicarbonate (baking soda).. to try and help avoid this flavor... It is not terrible, but it isn't a flavor that I want in my dark brews.

 

[BucketHead]

Also to add... I do not have a water report.... it is too expensive here to get one ($350+).. not worth the expense to me. I did take a TDS meter and I do have tds of 74, which leads me to think that the water is very soft. I do filter my water, through particulate and carbon filters followed by particulate again... just to help remove the very small amount of chlorine from the water.. so that I don't have to boil the water and cool it prior to brewing.
considering that I am successful with all the light colored beers I make, I think my assesment of the water is good. Even though there is tds of 74, I treat it like RO water and add my salts for Ca and So concentrations.
It is only the dark beers that I have difficulty with and am trying to resolve. Thanks to anyone who can shed some light on this for me.

 

[BigEd]

"Soft" is way too general of a description to determine what adjustments are needed for your brewing water. Soft water means it's low in Calcium but that alone is not enough information to figure out your problem. Other factors in the water's content and in particular the residual alkalinity are very important for brewing purposes. Telling us where you are would be a start. It's possible there are members who are familiar with the water characteristics in your area and could pass on their experiences. Frankly, unless you get an accurate breakdown of your water you're shooting blindfolded at the target. I would also suggest you read the water section in the Brew Science section here at HBT. There is a wealth of general and specific information available on water there. If you cannot find a local lab to do a reasonably priced water test perhaps a mail order version can be found. In North America the brewing water tests done by Ward Labs are very good, very popular, and very affordable.

 

[BucketHead]

Hi BigEd, thanks for the reply.
I am in the southern portion of Chile, I understand that my post is vague and not specific enough.
I have tried many times to get some indication of what the water profile here is, to no avail, I don't know the residual hardness, alkalinity, but using phosphoric acid, I can bring it down from the original pH of 7.6 to below 6 very easily, less than 2ml of acid in 9 gallons of water (strike volume).

My inquiry is more to understand if brewing with water without much or any residual alkalinity, and making a Stout or Porter would give sour flavors or ... what would the flavor/taste effects be of brewing dark beers with 'soft' water. (my finished Porter pH is at 4.6, so not too terribly low... mash pH has always been in proper range also) * I normally don't mash the dark grains, I steep them and add them at last 5 minutes of boil.

 

[BigEd]

Understand that it is the pH of the mash, not the pH of the water that is the critical target here. In crude terms the residual alkalinity of the water indicates how much effort will be required to lower the pH. I'm no chemist but soft water usually comes with low residual alkalinity. Low alkalinity water is generally desired for the brewing of light colored beers. Water with high levels of residual alkalinity are ususally a traditional match for dark beers as the high acidity of dark roasted grains will balance the higher alkalinity in the water during the mash. I would again suggest the Brew Science section. It's not a bad idea to re-post your question there as it might have a better chance of being seen by some one with more technical expertise.

 

[Twinkeelfool]

You can try adding dark malts late in the mash ( 15mins ). I have soft water and have been doing that for many years with great results. I then don’t have to worry about adding anything to try to harden my water when mashing. You may need to add more than you normally would, but I keep the amounts the same.
I’d always have acrid/harsh dark beers but when I tried this, they were much better.
It’s easy enough to try

 

[BucketHead]

Thank you Twink, I also don't add my dark malts to the mash.... I almost always make a steeped liquid, or when I didn't plan well... I would add them during Vorlauf.
It may just be the taste of the dark malts that I have... but the Porter and Stouts that I make are very good for the first month, then they start developing an astringent or sour taste, mildly sour...but still not pleasant to my taste buds. I am still trying to work through this... I added 16 gms of bicarbonate to my last Stout brew... but it is still in the fermentation stage.. so I will not know for some time how this will come out. Glad to know that you were able to eliminate this event from your brews. Maybe I'm using too much dark grain trying to get the SRM I'm looking for. In my previous brew, which has the problem I'm discussing, I used 3% Roasted Barley and 1% Black Patent.

 

[Twinkeelfool]

Hopefully you figure it soon mate