What do I need to add to Reverse Osmosis water for homebrewing?

[wantonsoup]

I'm thinking of switching to RO water for homebrewing (long story), but I figure I need to add things to the water to make it best for brewing. What do I need to do? Is there a rule of thumb here with this? Thanks.

 

[day_trippr]

[If you are thinking of buying a system] bottom line issues are output capacity given your source water pressure, its TDS level, and whether it comes bearing chlorine or chloramine.

Give HBT member Russ @Buckeye_Hydro a PM, he knows this stuff cold and may save you ill-spent $$...

Cheers!

 

[flars]

There's no rule of thumb but a good start for using RO water would be Bru'n Water.

 

[Dcpcooks]

CaCl and gypsum are common additions for most styles. You’ll also need some type of acid or acidulated malt to get the ph inline for light beers.

Read the water primer in the brewing science section for a great breakdown of the process

 

[mongoose33]

It depends on the malt and other adjuncts you're using. I commonly use 1 gallon of my tap water and 6 or 7 gallons of RO. For the beer styles I brew, which tend to be lighter, I'll add some Epsom Salts (MgSO4), Calcium Chloride (CaCL2), usually a couple/three ml of Lactic Acid.

You need a calculator/spreadsheet of some sort to do this effectively. BrunWater is a popular one, so is EZWater.

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Darker malt tends to be more acidic, such that when you get to things like chocolate malt, it's very acidic compared to standard 2-row. This means that the type(s) of malt you're using dictate the additions to the water. Since dark malt is too acidic to just use RO without any water amendments, you may need to add something to bring the pH up.

Lighter malt is less acidic, so you may need to add something to bring the pH down.

And then you have the ratio and amounts of chloride and sulfate. A low ratio promotes bitterness, a high ratio maltiness. So you can either put it in the balanced category, or play with the amounts and ratio to get what you want.

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I know how confusing this can sound. It's possible to calculate all this by hand, but the spreadsheets are so great at it that there's no reason to self-flagellate over water additions.

PS: Why did some areas of the world become famous for their dark beer while others for lighter beers? Answer: that's what the water allowed them to brew well. Since nobody in the early days of brewing knew anything about water and pH and malts and such, trial and error got them there. Dark beers were best in areas of alkaline water; the dark malts were acidic enough to offset the alkalinity of the water; light beers in areas where water was not mineralized, at least, not much, so much less acidic malts were best. Ever wonder why Stouts and Porters came from England, while light lagers came from Germany? Now you know.

And since all this affects pH (duh!) and pH is important for proper mashing.....

BTW, it was this one thing that suddenly made understanding water more accessible to me.