Water Question - RO Water/tap Water

[Matteo57]

If you send in a water sample to white labs (or another lab) to get your water chemistry info so you know what you are dealing with, does it matter if you use RO water or not to build your water profile up? I was told that you could build a better water profile from half RO water and half tap water (that you know the profile for) and then adjust the salts and minerals from there. The guy said that it would be better than just building the 100% tap water up to what i want. I don't understand how this would make sense but I don't really understand water much yet, I'm just starting to dabble in it. He didn't really explain why he was saying such either though.
I do use a water filter like what you can buy at morebeer connected to the water faucet outside where I would normally have a hose connected. I then plug in my water profile from white labs into Palmers calculator or EZ Water calculator and go from there.

Thanks for any info, it's much appreciated!

 

[schematix]

It all depends on what your water is like. The thing with water is that its really easy to add, but not so much take away those ions.

You can use RO water to dilute the ion concentration in your water. For example. if you sulfates are at 150 ppm, but the beer you're making calls for it at 75ppm, you could dilute it 50/50. However if that recipe called for 0ppm of bicarbonate and you have even 50, well you just can't get there until you reach 100% dilution.

The best thing about RO water is that it gives you a repeatable baseline.

 

[ajdelange]

In order to reproduce a desired ion profile from tap water with a given ion profile one adds, in cases where it is desired to increase the concentration of an ion, a salt that contains that ion and, in cases where it is desired to decrease the concentration of an ion, low ion water. If no ion concentration in the tap water exceeds the concentration desired only salts will be needed. If any ion in the tap water exceeds the desired concentration then low ion water will be added which will dilute not only the concentration of the problem ion but all other ions as well so that salts may be needed to make them up. It is, thus, possible to synthesize any physically realizable profile from tap water, salts and RO water but after fiddling with doing this a couple of times most conclude that it is simpler to use just RO water and salts.

 

[mabrungard]

The suitability of blending tap and RO water depends upon your tap water quality. Some are so poorly suited for brewing that you could be better off with straight RO water. However, there is the argument that tap water can provide micro-nutrients that aid yeast performance. That is a possibility, but those micro-nutrients can be easily supplemented. The only components that I think could need supplementing are copper and zinc. Both are easily added.

It looks like you got your W name's mixed up above. I assume you are talking about Ward Labs and not White Labs...or has White started testing water?

 

[Malt]

It looks like you got your W name's mixed up above. I assume you are talking about Ward Labs and not White Labs...or has White started testing water?

White Labs does do water analyses, Catalog #SIT6000 - $101.

 

[ScrewyBrewer]

White Labs does do water analyses, Catalog #SIT6000 - $101.

It seems like $100.00, for a single tap water test, is nearly half the cost of a 90 gallon a day reverse osmosis system, which will yield water with consistent properties year round.

 

[Malt]

It seems like $100.00, for a single tap water test, is nearly half the cost of a 90 gallon a day reverse osmosis system, which will yield water with consistent properties year round.

Agreed, I was being sarcastic with regard to Martin's pondering of "unless White does?" Sure, if you have a spare $100. Of course, they cater more to commercial breweries than the homebrew market.