# Rain Water Treatment



## fraser_john (29/6/07)

I have nearly completed by brewery in the 6x9 meter shed I had built and have two nice new water tanks on it, to use fo brewing and chilling (recycle back into the tanks!). Anyway, I was wondering whether anyone else uses rainwater in their mash and whether or not they attempt to adjust the free ion (hardness etc) of the mash water and the sparge water.

Do you treat rainwater as totally ion free in some of the adjustment calculations?

Thanks for any advanced help!

John



To see the brewery, check the link, I have to get more updated pics this weekend as the RIMS setup has been moved in over the last few days and the beer related "trimings" have started to decorate the walls....http://rims-brewing.tripod.com/rims_brewing_brewery.htm


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## The King of Spain (29/6/07)

John

I use rainwater and have found that a tsp of Gypsum works well in ale mashes and a tsp of Calcium chloride (I use Damprid for this) works well in lagers in enhancing the malt taste.

Rainwater also has more oxygen in it than town water that has been stored for a long time and then piped a long distance (also good).


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## jimmy01 (29/6/07)

Hi John

I have started using rain water lately. Which I filter pre-use.
With pH of 6.8 compared to Brissie tap water at 8.0 I thought I would now need less Ca Suphate to hit mash ph. However I can't say I have noticed an improvement in inefficiency or taste.

I use Beersmith as a guide to water treatment depending on which style I am brewing

Cheers
Dave


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## goatherder (29/6/07)

John, I use rainwater for my brewing.

The biggest problem will be determining your base water composition. If you have access to some lab gear this will be easy - but for me, and most of us, this is a problem. I took mine to a pool shop and got some numbers which I think are in the ballpark.

Rainwater is mostly soft, but not always. The type of tank, how close you are to the sea or heavy industry, how much rain you get and how much birdshit is in your gutters will affect this. Accurate measurement is the only way to understand how much this affects you. Do not assume you are ion free - you definitely have ions, possibly in the moderately soft to the moderately hard range.

It isn't all doom and gloom though. In all likelihood, you will have water well suited to brewing a large range of styles. You may only have a problem with very pale or very dark beers. If you don't know that you have a problem, you probably don't have a problem and you shouldn't dick with your water.

If you still want to persist with water treatment (I couldn't help myself), you need to read Palmer. The well talked about path of matching famous brewing waters is a red-herring. Initial water pH is also a somewhat meaningless indication. The key concept is working with "residual alkalinity" to balance mash pH whilst at the same time controlling levels of sulphate and chloride ions to get the required flavour characteristics.

In my case, I got a feel for my calcium and carbonate levels from a pool shop analysis. I use these values when calculating residual alkalinity for my mash. I make the assumption that I am fairly low in sulphate, chloride and sodium, for a number of reasons. Therefore, if I am making a pale beer, I may need to decrease my mash pH. I normally use gypsum for this, provided I don't have to use too much. I use lactic acid if I don't want the sulphates. For a very dark beer, I think my sodium levels are low enough for me to use bicarb soda to raise my mash pH to hit the target 5.4-5.7.

Rainwater is an unknown but chances that it will brew most beers perfectly fine. Depending on where you are in the AG learning curve, there are probably a whole lot more things you can get better at before your water becomes a problem.


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## tangent (29/6/07)

i boil all my water for 90 minutes 
i'm starting to wonder if my gypsum additions are just causing more expensive beer stone. i only get it when i add it.


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## fraser_john (30/6/07)

Thanks guys! I might just try a few brews just straight and see how they end up!


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## redgums500 (30/6/07)

fraser_john said:


> Thanks guys! I might just try a few brews just straight and see how they end up!


 Fraser 

I had problems when we switched from bore water to rain water. Seemed that the stouts and heavy ales were lacking some Zing. On Ross's advice I just added a teaspoon of sea salt to the fermenter. The Zing is back.  

cheers
Redgums


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