Bru'n Water/Surly Bender/RO TDS

[THESOUNDBARRIER]

My tap water is not so good. It does not make good beer. I have a TDS meter, and it reads water from the tap as 565 ppm. That is really quite terrible. The water is loaded with bicarbonates and sodium, etc... It's really nasty stuff.

To deal with this, I purchased a pretty cool counter-top RO system that hooks up to my kitchen sink faucet. I bought a digital scale, so I can accurately get my ion levels squared away for different styles of beer with different elements. I found Bru'n Water and chose to use that program to help me out with this. More on that in a sec...

My initial reading after firing up the system came in at 036 ppm, which really shocked me. I got that reading after flushing the RO membrane for about 15 minutes. I thought that was a fantastic ppm level, considering how high my tap water clocks in. However, when I was on break at work today I fired up HomeBrewTalk and learned that anything above 025 ppm is not considered true RO water (according to Martin) - so this bummed me out pretty bad. I've been drinking the water for the past few days and have been loving it. I had to test my water again when I got home, just to be sure.

When I checked the TDS level this time, it came in at 018 ppm. Wow. So I do have RO water! I suppose it's possible that the RO membrane needed more than 15 minutes of run time to give me an accurate reading on my TDS meter.

I'm going to be Brewing NB's Surly Bender clone with custom water. I selected the balanced brown ale profile in Bru'n water, tinkered with the water adjustment calculator, and was able to get everything adjusted pretty much bang on. All my ppm levels look dead nuts accurate with what the desired water profile suggests and the program predicts a mash pH of 5.2. I think I did it right, but this is my first time using Bru'n Water, so I'm not 100% on this.

I'm going to try to attach two files so you homebrewers who know how to use this can check on me, if you want. Cheers.

 

[mabrungard]

I also find that an RO unit needs to be running for a while for it to produce lower TDS values. My unit does show somewhat higher TDS when it has been relatively static and that value drops when its producing a lot of water. The RO process does remove a percentage of the original TDS, so its not a surprise that your treated water has a bit more TDS. 25 ppm TDS is not necessarily a signal of failing performance. However, do learn what your machine normally outputs in terms of TDS. If you see that reading increase over time, then it is probably a sign that the membrane is failing and needs replacement. Hopefully, that is in a year or two.

Don't worry too much about getting ionic concentrations to exactly match a profile. There is nothing magical about the profiles. Just work the mineral additions to get the ion concentrations somewhere close to the profile and that should be good enough. Do take some time when you are drinking that beer and assess if you think you would like more or less of an ion based on what each ions reported flavor character is. Possibly increase or reduce certain concentrations in future brews to gain a better understanding of what YOU prefer. The good thing is that the color-based profiles in Bru'n Water are fairly modest in their mineralization and they are not likely to overwhelm your beer. Remember, we are brewing beer and the water should be firmly in the background for most styles. The most important thing is for your adjustments to produce an appropriate pH.

 

[THESOUNDBARRIER]

Thank you for your help! I really appreciate your response.

 

[Buckeye_Hydro]

I also find that an RO unit needs to be running for a while for it to produce lower TDS values.

Martin - What is the capacity of your RO - is this a commercial unit of residential-scale?

Does your permeate TDS improve over the course of one to several minutes, or are you talking about something longer?
Russ

 

[Buckeye_Hydro]

Folks should be aware of something referred to as TDS creep. This is common to all RO systems. When any RO is first turned on, you'll get a pulse of not-so-clean permeate (RO water). The length of time this pulse persists varies with a number of factors, but here's some example data from two test runs showing how that plays out with a 75 gpd residential scale RO system. You'll see that after about 60 seconds the RO water purity is where you'd expect it. You can determine how long this period lasts with your RO by experimenting a bit with your TDS meter.

Russ