Another question on water chemistry

[RonnieBiggs]

Hoping to pick the brains of the guys who understand water chemistry better than i do.
I have been adjusting my water profile and mash ph using Salts and lactic acid for a long time. I paid for a water profile so i knew my base mineral content, hardness, alkalinity, etc.
I have since moved town and found the water profile here pretty poor tasting, and paid for a water test, confirming less than ideal mineral contents for most of the styles i brew.
I have since bought a RO filter... bear with me.
Question 1-TDS meter shows negligible ppm after RO filtering So i can assume the hardness of the RO water as CaCO3 is negligible also?
Question 2-Can I also assume that the alkalinity as CaC03 of the RO water is also negligible??
Question 3 ( the one i would love some help with)- i assume once I add my desired amount of salts to the RO water to suit the beer style i can calculate the hardness using Mg Ca method, but what about the alkalinity post salt additions?? How do I get that, or at least in the ball park. Alkalinity as CaCO3 is one of the values i input into my water adjustment calculator but how do I get that after I've RO filtered my water and then added varying amounts of salts??

Am I worried to much about the alkalinity value? Should I just use a ball park figure for my water adjustment spreadsheet? How do you guys do it??

 

[Hoochin'Fool]

Question 1-TDS meter shows negligible ppm after RO filtering So i can assume the hardness of the RO water as CaCO3 is negligible also?
Question 2-Can I also assume that the alkalinity as CaC03 of the RO water is also negligible??
Question 3 ( the one i would love some help with)- i assume once I add my desired amount of salts to the RO water to suit the beer style i can calculate the hardness using Mg Ca method, but what about the alkalinity post salt additions?? How do I get that, or at least in the ball park. Alkalinity as CaCO3 is one of the values i input into my water adjustment calculator but how do I get that after I've RO filtered my water and then added varying amounts of salts??

Am I worried to much about the alkalinity value? Should I just use a ball park figure for my water adjustment spreadsheet? How do you guys do it??

disclaimer: not a chemist, but I can't think of any chemical (not even Hydrochloric acid) that could alter pH/buffering without registering as different from "pure H2O" to a TDS meter.

Use the TDS meter to confirm that your RO system is working properly. As long as the TDS meter says things are negligible, you can safely assume that you are working with essentially distilled water.

 

[dmtaylor]

It's safe to assume RO water is all zeroes, including alkalinity, the same as distilled water. Your brewery and your palate will not be able to tell any difference.

 

[jerrylotto]

I am a chemist and RO water is practically as pure as you can be as a starting point. Any ions you want require salt additions. And pH adjustment will swing wildly without buffering.

 

[Dgallo]

Correct on the assuming your pretty much have zero alkalinity. I don’t worry about the alkalinity much at all because when you target your ph, the acid will counteract that anyway (my base water starts at 124ppm of alkalinity). The only time I’d worry if I was above 180ppm, then I’d probably cut my base water with distilled. That said, with you using RO, you have nothing to worry about there

 

[VikeMan]

but what about the alkalinity post salt additions??

You're starting with virtually no alkalinity. Use software to hit flavor ion targets and the pH you want. Alkalinity shouldn't have a target per se.

 

[RonnieBiggs]

Thanks for the info, think I might have been going down the rabbit hole on that one.
Currently using EZ water for my water calculations, but not sure its still the best choice, do you guys recommend an alternative?

 

[BandonBrewingCo]

Thanks for the info, think I might have been going down the rabbit hole on that one.
Currently using EZ water for my water calculations, but not sure its still the best choice, do you guys recommend an alternative?

Brewfather has a water chemistry wizard that will get you most of the way there. I've timestamped the video so it should start at the water section

 

[Dgallo]

Thanks for the info, think I might have been going down the rabbit hole on that one.
Currently using EZ water for my water calculations, but not sure its still the best choice, do you guys recommend an alternative?

Bru’n water spreadsheet. Spot on with ph and ppms, especially when using RO water

 

[RonnieBiggs]

Thanks for the responses guys, definitely helping out

 

[RonnieBiggs]

Bru’n water spreadsheet. Spot on with ph and ppms, especially when using RO water

Yeah, seems like a well thought of solution to water chemistry, I'll check it out

 

[Yooper]

I use Brewer's Friend with my recipes, and it's always spot on with pH prediction for me.

As was mentioned, there is NEVER a target for alkalinity- just enough alkalinity to keep the mash pH in the desired 5.2-5.5ish area. Depending on the grainbill, like a cream ale or light lager, I still may need to add aciity even with RO water to get where I want to be. You won't ever have to add alkalinity unless you're making a beer with lots of roasted/dark malts with RO water.

I like to target 5.2 for dry stouts, and many of my lighter beers, and 5.5 for my oatmeal stout, but that's me being very anal about it. 5.3-5.4 is a good general goal for most beers.

 

[pfabsits]

Hoping to pick the brains of the guys who understand water chemistry better than i do.
I have been adjusting my water profile and mash ph using Salts and lactic acid for a long time. I paid for a water profile so i knew my base mineral content, hardness, alkalinity, etc.
I have since moved town and found the water profile here pretty poor tasting, and paid for a water test, confirming less than ideal mineral contents for most of the styles i brew.
I have since bought a RO filter... bear with me.
Question 1-TDS meter shows negligible ppm after RO filtering So i can assume the hardness of the RO water as CaCO3 is negligible also?
Question 2-Can I also assume that the alkalinity as CaC03 of the RO water is also negligible??
Question 3 ( the one i would love some help with)- i assume once I add my desired amount of salts to the RO water to suit the beer style i can calculate the hardness using Mg Ca method, but what about the alkalinity post salt additions?? How do I get that, or at least in the ball park. Alkalinity as CaCO3 is one of the values i input into my water adjustment calculator but how do I get that after I've RO filtered my water and then added varying amounts of salts??

Am I worried to much about the alkalinity value? Should I just use a ball park figure for my water adjustment spreadsheet? How do you guys do it??

A couple of things to note.

From my experience an RO system will produce water that is about 30 uS/cm or 15 ppm TDS (EC/2). There are not a lot of salts left in the water. It is close to zero. For a lab that needs high purity water, it is common to filter incoming water by RO to remove the majority of salts and then pass through ion exchange (DI) resin to remove the remaining. At that point the water has all the salts removed and will have a EC reading of 0.055 uS/cm.

What are the types of salts in water? Depends on the source water. Lake water tends to be low since it acts like a bowl and catches water. Lake Michigan in Chicago has 300 uS/cm EC. In Chicago, the majority of the suburbs are on city water that is produced by 3 water plants (including the one next to Navy Pier). About 30 miles from downtown is a town called Frankfort. The city there uses groundwater. The water is very hard and high in EC (3X Lake MI) since their is a lot of limestone (calcium carbonate ) in the ground that is picked up as the rain water percolates through the ground.

The Frankfort water is high in Calcium, which causes the high reading in hardness. The carbonate portion will make it high in alkalinity. Attached is docuemnt that shows the differences between different bodies of water. It also shows how a water softener is used to remove the hardness but the alkalinity remains. It also shows how the RO system then removes the alkalinity.

If you wanted to see the impact of alkalinity and its' buffering capacity then it is easy to do with a pH meter.
1) Fill two glasses with RO water
2) Add a teaspoon of baking soda (Sodium bicarbonate) to one of the glasses
3) Measure the pH of both glasses. Start with the one with baking soda and then go to the other one. It is okay to contaminate the one without baking soda. It will help with the measurement since pH meters needs around 100 uS/cm of EC to work properly.
4) Observe the values. They should be in the pH 7.2 to 7.6 pH range.
5) Take some vinegar (acid) and a eye dropper to count the number of drops it takes to change the pH value from pH 7 to pH 4. The one without baking soda will take 2-3 drops. The one with baking soda will not budge until a large amount of the acid is added. A 1/4 cup might budge it down to pH 6 and you will see the CO2 being gassed off as the reaction between the acid and carbonate occurs.

Alkalinity is the buffering capacity or the resistance of the water to change from an acid. RO water has little to no alkalinity.

My understanding, and many others with more knowledge of brewing can confirm, is that when using RO water the water then has to be rebuilt with the salts/minerals for the beer style that you are going to brew. It is common for a micro-brewery to use a commercial RO to produce water for their brewing process since it removes any variances in water quality from the source water.

Water, A Comprehensive Guide for Brewers by John Palmer and Colin Kaminski is a great resource if you want to understand water chemistry. It goes into great detail about alkalinity and hardness in brewing.

 

[hottpeper13]

When my RO filters are replaced the TDS is <5 ppm's. They get replaced at 15 ppm's.

 

[pfabsits]

When my RO filters are replaced the TDS is <5 ppm's. They get replaced at 15 ppm's.

There are typically three filters for an RO system. One is a cloth/fiber that removes the particulate. The other is a carbon filter, which removes chlorine and odors. The last is the RO membrane itself. The RO membrane is the one that removes the salts/ions from the water.

The sediment and carbon filter are the ones that are typically replaced every 6 months. The RO membrane rarely gets replaced. It is replaced when the membrane fails. The TDS reading will be the same as untreated water. Other than that it should provide for >95% reduction of salts.

Unless you are changing the RO membrane, the carbon and sedimentation filter should have no impact on TDS. They are pre-RO membrane and not after.

It would be of interest to know the range of the TDS meter that you are using. EC meters typically have an accuracy of 2% full scale. For meters with a range of 0 - 1000 ppm that means the reading is accurate to +/- 20 ppm. For a 0 - 1999 ppm the accuracy would be = +/- 40 ppm. With either meter, a reading of 5 ppm is the same as 15 ppm since both readings are in accuracy statement.

Most meters, that a consumer use, are a amperometric design in which there are two pins that a voltage is supplied to. The conductivity is determined by the amount of current that passes between the two pins. To get a TDS reading the conductivity reading is multiplied by a factor. The majority of the meters use a 0.5 factor. Meaning that a 10 uS/cm reading = 5 ppm.

If I had to guess, I am guessing that the difference in readings from replacing the filters might be related to temperature compensation. EC/TDS are extremely sensitive to temperature variations. They will vary 2%/oC from 25 oC/78 oF. If the tester has the themistor built in the probe then it can take time to reach thermo-equilibrium. The readings will drift until it stabilizes.

When I built a flow cell/probe for high purity water testing, the temperature correction coefficient was 5.5%/oC. That was with water at 0.055 uS/cm. I would guess that at 2.5 uS/cm (5 ppm) the correction coefficient is in between 2 and 5.5%. The 2% is based on water that would be higher in EC.

The other guess that I have is that the TDS meter had some salt on it from before. It takes next to nothing to move the reading from 5 -15 ppm. Read some DI water and place 1 grain of table salt in the glass and watch the value increase. For 10 ppm it is less than a grain of salt. I would soak the probe in RO water for a couple of minutes and rinse with RO water then test.

 

[hottpeper13]

I'll check it out. I'm making brewing liquor today for a brew day tomorrow.

 

[RonnieBiggs]

A couple of things to note.

From my experience an RO system will produce water that is about 30 uS/cm or 15 ppm TDS (EC/2). There are not a lot of salts left in the water. It is close to zero. For a lab that needs high purity water, it is common to filter incoming water by RO to remove the majority of salts and then pass through ion exchange (DI) resin to remove the remaining. At that point the water has all the salts removed and will have a EC reading of 0.055 uS/cm.

What are the types of salts in water? Depends on the source water. Lake water tends to be low since it acts like a bowl and catches water. Lake Michigan in Chicago has 300 uS/cm EC. In Chicago, the majority of the suburbs are on city water that is produced by 3 water plants (including the one next to Navy Pier). About 30 miles from downtown is a town called Frankfort. The city there uses groundwater. The water is very hard and high in EC (3X Lake MI) since their is a lot of limestone (calcium carbonate ) in the ground that is picked up as the rain water percolates through the ground.

The Frankfort water is high in Calcium, which causes the high reading in hardness. The carbonate portion will make it high in alkalinity. Attached is docuemnt that shows the differences between different bodies of water. It also shows how a water softener is used to remove the hardness but the alkalinity remains. It also shows how the RO system then removes the alkalinity.

If you wanted to see the impact of alkalinity and its' buffering capacity then it is easy to do with a pH meter.
1) Fill two glasses with RO water
2) Add a teaspoon of baking soda (Sodium bicarbonate) to one of the glasses
3) Measure the pH of both glasses. Start with the one with baking soda and then go to the other one. It is okay to contaminate the one without baking soda. It will help with the measurement since pH meters needs around 100 uS/cm of EC to work properly.
4) Observe the values. They should be in the pH 7.2 to 7.6 pH range.
5) Take some vinegar (acid) and a eye dropper to count the number of drops it takes to change the pH value from pH 7 to pH 4. The one without baking soda will take 2-3 drops. The one with baking soda will not budge until a large amount of the acid is added. A 1/4 cup might budge it down to pH 6 and you will see the CO2 being gassed off as the reaction between the acid and carbonate occurs.

Alkalinity is the buffering capacity or the resistance of the water to change from an acid. RO water has little to no alkalinity.

My understanding, and many others with more knowledge of brewing can confirm, is that when using RO water the water then has to be rebuilt with the salts/minerals for the beer style that you are going to brew. It is common for a micro-brewery to use a commercial RO to produce water for their brewing process since it removes any variances in water quality from the source water.

Water, A Comprehensive Guide for Brewers by John Palmer and Colin Kaminski is a great resource if you want to understand water chemistry. It goes into great detail about alkalinity and hardness in brewing.

Your comment about TDS reduction of RO system seems inline with my results. My starting TDS levels are around 250ppm, and my filtered water reads 18ppm. I was hoping it would filter a little more out but with that high a starting point i think that's acceptable. To compensate i just add a the 18ppm remaining across the board in line with the water report i have.

 

[Bobby_M]

If you know your starting water stats, a reasonable approximation is to just reduce the starting numbers by 95% for the RO profile you're starting with. It's going to be pretty close to zero so even if you set distilled as the source it's close enough.

 

[RonnieBiggs]

If you know your starting water stats, a reasonable approximation is to just reduce the starting numbers by 95% for the RO profile you're starting with. It's going to be pretty close to zero so even if you set distilled as the source it's close enough.

Yeah, that's a better way to phrase what i was trying to say

 

[mabrungard]

The RO profile presented in Bru'n Water represents the performance of a well operating membrane that is fed raw water that's over 650 ppm TDS. The Bru'n Water RO TDS is 30 ppm which is about 96% rejection and that's par for RO performance.

If you are measuring TDS out of your machine that is significantly lower, I'd go ahead and ratio the values shown in the Bru'n Water RO profile by however much you feel is appropriate. In the end, the ions will be near zero and you wouldn't be able to taste a difference anyhow.

To the person that says they replace their RO membrane if TDS gets over 15 ppm: That's an incredibly wasteful and expensive approach that provides NO useful effect. I'd not worry about membrane replacement until its over 50 ppm TDS.

 

[hottpeper13]

So I left the meter in RO water for a little over an hour and it read 15 ppm. I'm gonna roll with it. I do use an Iron out and softener before RO. Never measured the raw water.