RO water adjustments: Just not getting it

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hops2it

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I've been thinking of switching over to all RO water and I'm just not sure if it's necessary or worth it to add anything to straight RO. On Brewer's Friend, I see these:

Chalk CaCO3
Baking Soda NaHCO3
Gypsum CaSO4
Calcium Chloride CaCl2
Epsom Salt MgSO4
Canning Salt NaCl

...and I've also heard lactic acid mentioned. I have tinkered with the numbers a little on there and I somewhat get that various styles could use some tweaks to make a water profile conducive to that style of beer, etc but that might be a little beyond my level of interest.

In a nutshell, I'm just wondering what recommended additions (if any) I should add to straight RO water for the purpose of home brewing the vast majority of beers. So what I'm really getting at...is RO water inherently lacking for the purpose of homebrewing without some minor tweaks ahead of time? Or is RO water fine and dandy to start with and if the brewer wants to micromange it further, that's up to them?
 
RO by itself doesn't really have sufficient mineral/dissolved-ion content for yeast health and beer character unless you're making particularly light or low-gravity beers (i.e., pilsner or light lager).

Tools like Bru'n Water and BeerSmith have stored water profiles that you can add salts to RO water to emulate, and you should pick a style that's appropriate for the style you're brewing, or a region that's famous for that style. Yellow Balanced for middling pale ale, London for malty brown, Burton for hoppy pale, Munich, Dortmund, Pilsn, etc.

Many (very respected) people debate the utility of going for specific areas' water profiles, but RO by itself is a bit bare for most styles.

-Rich
 
If you would like to go in the direction of minimal mineral additions, read the Water Primer sticky that is at the top of this forum. Those are AJ's recommendations for minimum water additions when using RO or distilled water.

You do want to add a minimum level of Calcium to your water or several brewing problems can be created and the beer flavor tends to be a little bland.
 
If you would like to go in the direction of minimal mineral additions, read the Water Primer sticky that is at the top of this forum. Those are AJ's recommendations for minimum water additions when using RO or distilled water.

You do want to add a minimum level of Calcium to your water or several brewing problems can be created and the beer flavor tends to be a little bland.

Sounds good. Yeah I read that sticky in it's entirety a couple of years ago and I'm not up for that much reading again so thanks for the reminder. Just to be sure, I'm looking at the OP and this quote for baseline right?

Baseline: Add 1 tsp of calcium chloride dihydrate (what your LHBS sells) to each 5 gallons of water treated. Add 2% sauermalz to the grist.

So I'm to understand that the sauermalz can be added into the mash tun and then stirred in at the beginning of the mash?
 
I want to just mention a lesson I recently learned: Not all RO water is created equal. I once heard a number of brewers tell me that RO is 'close enough to distilled to not matter' and I brewed with it as if it were distilled. Then I got suspicious and had it analyzed by Ward Labs (Martin, you may remember this)... it had about 50ppm TDS and 50ppm bicarbonate and it was not the water I needed to use to dilute my higher-than-I-would-like bicarb. My point: If you don't know what's in your RO water, it makes it hard to understand where your water numbers are and what to add, etc. You're playing a guessing game. Hops2it, I feel your pain. I have been on a water odyssey for over a year and have made some terrible beers during my experimentation. But I have also made some great beers so stay with it. The great thing about this particular forum is that you have people like Martin, AJ DeLange and Kai all contributing and posting here and these are the water and brewing rock stars. Cheers.
 
Very interesting kenlenard- what exactly is the explanation for your RO water still being so hard? Are you using an RO filter on your home water source or getting RO water from the store?

I get it at my local grocery store in bulk for 49¢ a gallon. But it sounds like the technology has its variables and when people don't maintain the system properly, your results are going to be all over the place. My source water has 138ppm of bicarbonate and I was diluting with water that I thought was close to zero. 50% would mean 69ppm bicarb but with this RO water I was still close to 90ppm. So I switched over to distilled for all my diluting. I know the numbers on the distilled (zero) and I know my numbers so this way I know exactly what's in the water, what I should add, etc.
 
I hear ya pal, my well water is 358ppm bicarbonate. I put in a RO system for diluting my brewing water but still occasionally have astringency I attribute to the water. Might have to send off a few sample to the lab and see just how pure my "filtered" water is.

Sorry to thread jack.
 
For anyone using RO water, having a TDS meter is a very valuable quality assurance check on the water. This applies to both people with their own machines and those that purchase from a vending machine. Membranes eventually wear out and the water quality goes down. The TDS meter alerts you of this condition.
 
For anyone using RO water, having a TDS meter is a very valuable quality assurance check on the water. This applies to both people with their own machines and those that purchase from a vending machine. Membranes eventually wear out and the water quality goes down. The TDS meter alerts you of this condition.

I understand the meters are inexpensive and they'll help you to know what's in your water. At some point I was tired of guessing about the water and I wanted to know. I live in an area where many homebrewers use the same water and send samples to Ward Labs and the numbers always come back the same or very, very close. I have sent my water for analysis twice and the numbers were right on. So I am comfortable with my source water but then this bulk RO water threw me a curve so I went with distilled. Very tricky to know what to add or how to treat when you don't know what's in the water and I'm convinced that water composition is one of the main keys to making stellar beer. Cheers.
 
For anyone using RO water, having a TDS meter is a very valuable quality assurance check on the water. This applies to both people with their own machines and those that purchase from a vending machine. Membranes eventually wear out and the water quality goes down. The TDS meter alerts you of this condition.

I also found that using an aquarium "hardness" detector worked well for me.

It's the "drops" kind that measure GH and KH. Every so often, I check it, and the KH is always one drop from my RO water, which means 16-17 ppm of carbonate hardness.

I happen to have a little aquarium, so I had that on hand.
 
For anyone using RO water, having a TDS meter is a very valuable quality assurance check on the water. This applies to both people with their own machines and those that purchase from a vending machine. Membranes eventually wear out and the water quality goes down. The TDS meter alerts you of this condition.

The $64,000 question then, is, at what point are the TDS too high? The carboy of RO water I just bought reads 8ppm, while the same water tested at 3ppm a few weeks ago. Is this a sign the membrane is wearing out, or does it seem like a reasonable amount of variation?
 
The $64,000 question then, is, at what point are the TDS too high? The carboy of RO water I just bought reads 8ppm, while the same water tested at 3ppm a few weeks ago. Is this a sign the membrane is wearing out, or does it seem like a reasonable amount of variation?

Excellent question and discussion here! I'm wondering what all I should be testing as I happen to work at a water treatment plant and we have a fully certified lab. I was intending on purchasing water from a supermarket vending machine setup.
 
The $64,000 question then, is, at what point are the TDS too high? The carboy of RO water I just bought reads 8ppm, while the same water tested at 3ppm a few weeks ago. Is this a sign the membrane is wearing out, or does it seem like a reasonable amount of variation?

There may be some variation in the RO quality, if the source water quality varies. But what you should monitor is if there is a consistent increase in TDS. Generally, TDS should hover in a narrow range. When it starts to climb, its then time to replace the membrane. By the time the TDS quadruples, its time to get that membrane replaced. This sort of monitoring is probably not to possible for brewers buying their water from a machine. But for those vending machine patrons, reconsider using their water if the TDS is above 50 ppm. 50 is pretty high for RO water.
 
Can I assume that source water with higher TDS and bicarb numbers are tougher on the RO equipment or might require the membranes to be replaced more often? If a grocery store RO dispenser was starting with very soft water vs. a machine that started with higher bicarb or TDS numbers... which machine would last longer/work better/be more efficient/be more likely to provide consistently good RO water? At this point I'm just always keeping my eye open for good prices on distilled water. Occasionally I see it for 69¢ a gallon and then I jump on it. Cheers.
 
Yes, higher TDS requires a higher water wasting rate to avoid fouling the membrane prematurely. Given that most home systems have a fixed wasting rate, the implication is that the membrane on a home system will be fouled more quickly with higher TDS water. However, TDS is not the whole story. The nature of the TDS also has an important effect. If the water has high Ca, Mg, or silicate which are more prone to forming scale, then the membrane is more likely to foul. If the water is low in those ions, then the system is likely to last longer. Using ion-exchange softened water does improve the life of RO systems.
 
There may be some variation in the RO quality, if the source water quality varies. But what you should monitor is if there is a consistent increase in TDS. Generally, TDS should hover in a narrow range. When it starts to climb, its then time to replace the membrane. By the time the TDS quadruples, its time to get that membrane replaced. This sort of monitoring is probably not to possible for brewers buying their water from a machine. But for those vending machine patrons, reconsider using their water if the TDS is above 50 ppm. 50 is pretty high for RO water.


Well I tested my store's RO water. It had no real measurable alkalinity or hardness (via titration), but it shows 82 TDS. Sigh. Not sure how important that is in the grand scale. If the hardness and alkalinity are knocked out, should I still care about TDS?
 
Well I tested my store's RO water. It had no real measurable alkalinity or hardness (via titration), but it shows 82 TDS. Sigh. Not sure how important that is in the grand scale. If the hardness and alkalinity are knocked out, should I still care about TDS?

Interesting. It occurs to me that an RO water machine is a great way to trick people into buying fancy water but it's really just tap water. Many times I stood there waiting for my 5-gallon bottle to fill thinking, "This is probably just f***ing tap water" which is why I eventually sent a sample into Ward. I wish I could help with the TDS but I'm not sure how it comes into play in brewing. I concentrate on the big 6 (Ca, Mg, Na, Cl, SO4, HCO3) and don't really look into the other stuff. The TDS in my source water is 264. Cheers.
 
Thanks Ken. Yeah its definitely being treated because our hardness is normally 120-150 and our total alkalinity usually runs about 70. Also, our pH is around 9.5 and the store water was 7.6. I'm guessing it'd suffice for .39 a gallon.
 
Well I tested my store's RO water. It had no real measurable alkalinity or hardness (via titration), but it shows 82 TDS. Sigh. Not sure how important that is in the grand scale. If the hardness and alkalinity are knocked out, should I still care about TDS?

Its probably still better than the tap water. The lack of hardness is not a surprise since the divalent Ca and Mg ions are preferentially removed from the product water by the RO process. If the local water is really hard, the machine may also have some sort of ion-exchange pretreatment that takes out the Ca and Mg and inserts Na or K. The RO product water has somewhat high Na or K. But given the TDS reading, the Na or K probably isn't that high to make it unusable. 82 ppm is not good, but its not a disaster. Do keep an eye on the reading and contact the machine operator to complain that the machine is not producing RO quality water.
 
Will do. I'll complain to the store manager. They're typically rather accomodating there. Although they might wish they'd have not let me grab a sample of the water now. I went in there yesterday and asked the manager if I could do that before investing in a couple of their 5 gallon refillable carboys. I was real honest with him...said I'm thinking of using this for homebrew water but I need to know it meets my qualifications. :D
 
So is an RO filter supposed to remove the hardness from water? I but gallons of water at Wal-mart and have the choice between RO or distilled. Both the gallons say the source is the Ft. Worth municipal water supply. I usually only add one or two gallons in my mash to a five gallon batch. Should I go for distilled just to make sure?

Any reason not to go with distilled? Thanks
 
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