Soft Water Low Alk

[YanknOnion]

My tank water here in Bermuda works fine for IPA's, but what would be (on a very basic level) an addition to make for darker beers? The more I read about water chemistry, the more confused I get. I don't have access to water testing lab for anything other than bacteria as we collect rainwater in under house tanks here. All I know about it is it is near 50 -70 in total hardness, Ph around 7.6 with alk around 60. (numbers come from pool test kit as wife has pool service)Any suggestions appreciated

 

[mchrispen]

Assuming you are doing all grain... If your numbers are correct, the you have fairly good water for brewing... I would start here with the Primer. It should do you very well without getting too complicated. Dark beers are addressed.

If you are doing extract brewing... then there should be no real need to add any minerals. They are already in the extract.

Since you are using rain water - perhaps someone can chime in on sanitation. I believe that a slow filter with active charcoal can help out, but not sure about the bacterial issues. Since the beer gets boiled for 60 minutes or more, I am fairly certain you will be fine. I would only used boiled water after the boil for any top ups or sanitation.

 

[ajdelange]

All I know about it is it is near 50 -70 in total hardness, Ph around 7.6 with alk around 60. Any suggestions appreciated

I'd be very surprised to find those levels of hardness or alkalinity in rain water. It is essentially distilled water which has fallen through the air and as such has dissolved some carbon dioxide and dust and, in your case as you live on an island, salt crystals. If there is lots of limestone around there will be some particles of that suspended in the air too and some hardness and alkalinity but 60 ppm as CaCO3 of each seems a lot. Where did you get those numbers?

You can obtain simple alkalinity and hardness tests from hardware stores and pet stores (that cater to the aquarium trade).

A water that is very soft (and we'll assume yours is until we get some confirmation that the hardness and alkalinity are really that high) needs only a small amount of calcium chloride (and possibly calcium sulfate if you find you like sulfate) and some sauermalz or lactic to lower pH. For a dark beer you would use less sauermalz or acid because the dark malts will be supplying a portion or all of this acid.

 

[mabrungard]

Is the tank water supplemented with groundwater? I am surprised that your hardness and alkalinity values would be anything other than very low for rainwater.

That water should be well suited as a starting point for brewing if it is just rainwater. The Water Primer is well suited for brewing pale beers. You may need to add some alkalinity for some darker styles, but that should be manageable with baking soda additions to the mashing water. Do recognize that the acid or acid malt additions are pretty important for the pale styles since the mash will still need a little help to get the pH down...even with RO, distilled, or rainwater.

As long as you aren't adding the tank water to the brewing process in any way that is not boiled, I wouldn't worry at all about water sanitation. That is what the brewing process is for.

 

[YanknOnion]

We collect rainwater from the roof and it is stored in underground tank. Got samples from using pool test kit. (Wife has pool service, so fairly confident about numbers), Thanks for the tip, much appreciated, I'll look into the primer

 

[YanknOnion]

Doing all grains, but you brought up something I never thought of about sanitizing water needing to be boiled. Wouldn't the sanitizer take care of that? I'm using star san. Thanks for the tip. Cheers

 

[ajdelange]

We collect rainwater from the roof and it is stored in underground tank. Got samples from using pool test kit. (Wife has pool service, so fairly confident about numbers)

Those numbers go with water that is in equilibrium simultaneously with limestone and the air. Is the 'tank' hollowed out of limestone? If so those numbers make sense. If not they don't. At least not to me. But it could be some mechanism I don't understand. Perhaps falling rain drops capture (or nucleate on) coral dust particles which are carried into the cistern with the drops and react slowly to come, eventually, to CaCO3/CO2 equilibrium. OTOH a quick search on the net for rain water chemistries indicates typical total ion contents of about 0.1 mEq/L and pH maximizing around 7.3. Hardness of 60 ppm as CaCO3 represents cation concentration of 1.2 mEq/L and alkalinity of 60 another 1.1 of anions for a total of 2.2 which is 20 times what the researchers typically find.

 

[YanknOnion]

Thanks for the suggestion adjelange, I tried 1/2 teas each of calcium chloride and sulfate Sunday in a chocolate porter. The tanks here are dug out of limestone and the house is built on top. Drains run into tank from roof. There are no freshwater lakes or rivers here, so that's how they do it.

 

[ajdelange]

So it all does all indeed make sense then.