Is all RO water the same?

[Grinder12000]

If wanted to use 100% RO water in a mash with additives would I need a water report on my RO water?

Thinking out loud here.

Or is that a bad idea? Our water sucks.

 

[Grizzlybrew]

2 things...

First - If it's truly RO water, it should be nothing but H2O molecules - so it SHOULD be the same

Second - I think most people would recommend you NOT brew with RO water only. Yeast needs certain minerals to thrive. Sure, it will make beer, but not necessarily the best beer, especially not for all styles.

I would either use 'Spring' water or start with RO and add back your own salts/minerals. See John P's book for help with that one or Designing Great Beers. Maybe try half RO and half your s***ty water.

 

[blizzard]

Technically, all RO water is not the same and RO systems don't remove 100% of everything. But, for our purposes you can assume they are the same and that they are pure water and that you need to add in all of the minerals you want to have.

 

[Grinder12000]

Didn't say BREWING with 100%. Just mashing with fixed water.

 

[conpewter]

RO can be a good base to build water from, though I've heard how it is hard to get some minerals to dissolve because of PH. I agree that RO is the same enough to not matter for our purposes.

 

[ajdelange]

Solubility isn't an issue with the water (to any practical extent). It is an issue with the salts. Gypsum is not that soluble in water but if you are trying to dissolve more than wants to you are using too much. Calcium carbonate is essentially insoluble in water unless you supply carbonic (or another) acid and that's why you shouldn't try to dissolve calcium carbonate in RO (or other) water unless you are supplying carbonic acid which is definitely for advanced brewers only (who wouldn't, for the most part, choose to go that route).

 

[MNDan]

2 things...

First - If it's truly RO water, it should be nothing but H2O molecules - so it SHOULD be the same

You are thinking of deionized water. RO water still has some minerals left in it - it just reduces them by a large percentage, though the degree of reduction depnds on the source water, filter upkeep, efficiency, etc...

http://www.ag.ndsu.edu/pubs/h2oqual/watsys/ae1047w.htm

 

[H-ost]

Wait... I'm supposed to be adding to my RO water? This is news to me.

 

[ajdelange]

Yes, indeed. Suggest you start by reading the Primer and go on from there.

 

[MNDan]

My two favorite water links:

https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/

https://www.homebrewtalk.com/f128/ez-water-calculator-3-0-a-261001/

 

[Grinder12000]

Primer here rocks. I love that thread.