Guide to Reverse Osmosis Systems for Homebrewers

[hausofstrauss]

At some point in your brewing career you are going to become interested in taking your water chemistry to the next level. As part of that, you might come to the realization that you want to improve the quality of your water and stop using the water from a garden hose or you might want to cut down on the inconvenience of having to go to the store to get your water. I had waited a long time to do it, but I've had my system installed for 2 years now and I don't regret the expense one bit.

I put together a guide on reverse osmosis systems detailing

• The basic components of a RO (Reverse Osmosis) system
• Some of the considerations when choosing a system
• A brief explanation of how they work
• How I chose to install my system

Here is a link to the full guide:

http://fermware.com/reverse-osmosis-system-installation/

 

[petemoss]

Nice guide. Thanks for posting.

 

[hausofstrauss]

You're welcome. I hope it helps in selecting your system.

 

[gnef]

Back when I was in Texas and brewing at my parent's house, they were on well water which was entirely too hard, and then they had a softener, which also isn't great for brewing. I worked at a bio research lab that had an industrial RO system, and the professor let me draw off from that as much as I wanted, so I learned how to build my water profiles from scratch.

I now have a 25 GPD RO system for just drinking water, but like you, I've teed it off for the ice maker, as well as a water tap in the garage/basement. I also added an 11 gallon tank, so in total, I have access to at least 8 gallons of RO water at any one time (the bigger tank is good since my membrane is on the slow side).

Since I live in Atlanta, I don't really have to worry about the water like I did back in Texas, so I just use a GAC-10 carbon filter for the chloramine, and then do minor pH adjustments based on my grist.

Looks like a good guide for those that need RO though!

The only thing I would recommend you add, are some links or info on how to build water profiles from scratch, so that people browsing your site wouldn't try to brew all grain with straight RO water. There are some good spreadsheets and info out there, and you could even provide a guide for a basic water profile, an IPA, a stout, etc using basic brewing salts per gallon of water.

 

[opercularia]

I have been buying RO water and adding minerals since I first started paying attention to water quality. Since buying a TDS pen, I have discovered that my local source is scarcely better than my tap water (270 vs 330 mg/L!). I can still get 20 mg/L in the next town 35 km away, but that's a real pain.

I think I have to go to home RO, but have reservations. I will only use it for brewing. I am not averse to collecting water before a brewday, so a 5 gpd system would be totally adequate - collect for a few days before brewing in the same containers I presently buy water in. However, this size unit is not readily available. I also worry about "mothballing" a system for the winter months when brewing outside is worse than running out of stock. How do RO units react to long periods of no use? Are there any special procedures required if the water is not moved through them regularly?

Does anybody with an RO system deal with these same issues and, if so, how does it work?

 

[hausofstrauss]

The only thing I would recommend you add, are some links or info on how to build water profiles from scratch, so that people browsing your site wouldn't try to brew all grain with straight RO water. There are some good spreadsheets and info out there, and you could even provide a guide for a basic water profile, an IPA, a stout, etc using basic brewing salts per gallon of water.

Thanks for the suggestion. I will update to make sure the reader knows not to use straight RO.

Also, as far as building profiles from scratch. I'll have a new post on Monday that will pretty much address just that. Adding pre-set profiles to Beersmith3 so that you don't have to think. Just use the built in ingredient calculations.

 

[hausofstrauss]

How do RO units react to long periods of no use? Are there any special procedures required if the water is not moved through them regularly?

Does anybody with an RO system deal with these same issues and, if so, how does it work?

I can't say that it was the right thing to do, but when I was only using a carbon filter for my tap water and it was dedicated to brewing, I would disassemble and dry out the housing and filter between each use.

Then upon re-use, I would flow several gallons through it prior to preparing my brewing water. There was no scientific method to it or knowledge, I was just assuming some sort of funk would build up if I stored it wet.

 

[gnef]

I have been buying RO water and adding minerals since I first started paying attention to water quality. Since buying a TDS pen, I have discovered that my local source is scarcely better than my tap water (270 vs 330 mg/L!). I can still get 20 mg/L in the next town 35 km away, but that's a real pain.

I think I have to go to home RO, but have reservations. I will only use it for brewing. I am not averse to collecting water before a brewday, so a 5 gpd system would be totally adequate - collect for a few days before brewing in the same containers I presently buy water in. However, this size unit is not readily available. I also worry about "mothballing" a system for the winter months when brewing outside is worse than running out of stock. How do RO units react to long periods of no use? Are there any special procedures required if the water is not moved through them regularly?

Does anybody with an RO system deal with these same issues and, if so, how does it work?

Is there are a reason why you wouldn't want to use it for your drinking water and ice in the house?

I would say that if you use one of the quick disconnect style cartridges, you will have less to worry about, since they essentially come sanitized, and with the way they connect, it stays pretty sanitary for the life of the cartridge. My system is the Watts Premier RO-Pure (bought from Costco, if that makes any difference), and I really like the quick disconnect style filters. It is more expensive, but I inherently trust the packaging style more than bare filters in a box. I actually only use my RO system for drinking water and ice.

For brewing, I use a very specific carbon filter, a Pentek GAC-10. I used to use whatever I could find at home depot, but I never liked that the water could shortcut through the pleats of the filter. With the GAC-10, the filter itself forces the water through the entirety of the filter. I do throttle the water going to the carbon filter, as it is only rated for 1 GPM, so I set it for about .7 GPM with my flow meter and also set it to automatically shut off when I get to my target volume. I also flush 5 gallons before I collect for my strike every brew day, as some times I haven't brewed in months. I replace the GAC-10 filter annually, and now that I have the flow meter, it also keeps track of total volume through the filter.

 

[matt_m]

Curious about your choice of a small tank. I've been thinking about adding a 20 gallon tank to our system so I can use it for brewing. The dual 4 gallon tanks only provide about 6 gallons at once (and I need to leave some for daily household uses. )

 

[augiedoggy]

whatever "Funk" your concerned about growing in the cartridge area would only be whats already in the pipes and water already?
I use my RO system on a pretty regular basis at home but I do have a GAC filter for my water at my camp trailer and it sits sometimes for months without any issues.

 

[Genuine]

Thanks for the guide! I've been toying with the idea of this. I don't mind going to the store to grab distilled water but this would be easier.

 

[ScrewyBrewer]

@hausofstrauss looks exactly like the SpectrePure CSP system I use.

 

[Buckeye_Hydro]

Great to see all the interest in RO - it is a cool technology/piece of equipment!

A few comments on the content of the guide:

Number of filter stages (more is better??).

In general, folks new to RO place too much emphasis on the "more is better" line of thinking. For a typical RO with an atmospheric tank treating chlorinated water, think of a 3 stage as your default configuration:
Sediment filter->carbon block->RO membrane

If you want a pressurized storage tank, you'll need to add a fourth stage - a "Taste and Odor Filter."

If your tap water contains chloramines, you'll want an additional. high end carbon prefilter.

Daily throughput. Again, decide what your needs are. Ours is just for brewing and drinking water at two faucets. 75 gallons per day is completely sufficient for us. If you are starting a nano-brewery, you’ll probably need more.

It is the capacity of your RO membrane that drives the speed at which purified water will be produced. Realize that unless you provide factory spec conditions, you won't get the full production out of a membrane. The two most important factors in temps of speed of production are water pressure, and water temperature. The best residential-scale membranes in the US are made by (DOW) Filmtec. They are spec'ed at 77 degrees F and 50 psi. Other brands are typically spec'ed at 60 psi or 65 psi and 77F. Colder water and or lower water temperature will slow production. How much? We have a calculator for that here: https://www.buckeyehydro.com/calculator/

Stage 2 Granulated Activated Carbon (GAC): pre-filter reduces and removes: chlorine, volatile organic compounds (V.O.C), pesticides, nitrates, herbicides, tastes, odor, and disinfection by-products (Chloramines, THM, TCE)

Regarding prefilters - The diagram shows the use of GAC as a prefilter - this is to be avoided. A carbon block will typically offer much better performance. If you see standard GAC used as a prefilter I'd question the expertise of the vendor - it is typically used because of it's low cost, not because of its optimum functionality. Carbon blocks are only very marginally more expensive.

Regarding the position of your "Probe 2" on the inline TDS meter, a better location for that probe would be BEFORE the Taste and Odor Filter as the RO water will pick up TDS going through that carbon filter.

Since I care about the overall PPM and not necessarily the rejection rate, I’ll probably replace all of the filters when I see a PPM close to 20.

Realize that the TDS of your RO water needs to be measured with the pressure tank valve CLOSED if your goal is to evaluate the condition of your RO membrane. Also be aware that the TDS of your RO water tells you nothing about the condition of your prefilters or when to change them. The answer to our first FAQ ("When should I change my filters?") addresses this issue in detail, here: https://www.buckeyehydro.com/faq/

Russ

 

[Buckeye_Hydro]

I also worry about "mothballing" a system for the winter months when brewing outside is worse than running out of stock. How do RO units react to long periods of no use? Are there any special procedures required if the water is not moved through them regularly?

Any RO system should be used at least once a week.

 

[Buckeye_Hydro]

Curious about your choice of a small tank. I've been thinking about adding a 20 gallon tank to our system so I can use it for brewing. The dual 4 gallon tanks only provide about 6 gallons at once (and I need to leave some for daily household uses. )

A couple of things to consider regarding pressurized storage tanks:
You'll pay a price for using a pressure tank:

• the water from a full tank is less pure than the water straight from the RO membrane
• You'll produce relatively more "waste water" when using a pressure tank
• The speed at which you produce pure water will be reduced with a pressure tank.

Russ

 

[Buckeye_Hydro]

I use my RO system on a pretty regular basis at home but I do have a GAC filter for my water at my camp trailer and it sits sometimes for months without any issues.

Ahhh... I don't recommend you do this, especially with water you're going to drink.

 

[augiedoggy]

Ahhh... I don't recommend you do this, especially with water you're going to drink.

We dont drink it unless we make coffee with it and the water has been run for a bit before we use it for that but I'm curious why you dont recommend it?

 

[Buckeye_Hydro]

It's not uncommon for filter system with (or without for that matter) carbon filters to develop microbial growth in stagnant systems. Remember that everything downstream of the start of the carbon filter is dechlorinated - there's no disinfectant in it.

 

[matt_m]

How do you recommend storing a carbon filter? I have one I use today for my brewing water. I'm draining all the water from it but its likely staying wet long term. Same with the RV use case.

 

[Buckeye_Hydro]

What you want to avoid is stagnant water. With or without the filter being immersed in it. And remember that potable water systems should be sanitized periodically. We have instructions for sanitizing residential scale RO systems here: https://www.buckeyehydro.com/instructions/

Russ

 

[augiedoggy]

I get what your saying, I just figured since the water going in is chlorinated and disinfected and since its a sealed system more or less that the filter shouldnt have nasties inside it that kind of like a fermenter or keg setup, it would stay relatively clean inside. I have never gotten sick from doing it this way over the last 10-15 years Ive used the filter at my camp.. I replace them every summer. I may rethink my procedure now

 

[KevinP]

Is getting an RO/DI system even advisable if I only intend to use it ~once a month for brewing?

I may also hook it up to the fridge for water and ice but even that only gets used a couple times a month.

 

[MaxStout]

My RO system isn't hard-plumbed. It's in my utility room over the wash sink and I attach it to one of the hose fittings there. I don't brew very often, but I also use RO for coffee-making, and the room humidifier during winter (no white layer of salt on eveything!). I fill a couple 1-gallon jugs every week or so, and that keeps the system flushed and clean. I'm a happy Buckeye customer--I highly recommend them.

By the way, DI water tastes very flat. It's overkill for brewing, so just get an RO system.

 

[Buckeye_Hydro]

Is getting an RO/DI system even advisable if I only intend to use it ~once a month for brewing?

I may also hook it up to the fridge for water and ice but even that only gets used a couple times a month.

Like Max said - you'll want an RO, not an RODI.

With any RO system, you'll want to run it at least once a week. That's easy to do outside of brewing if you set it up to feed a little faucet on your kitchen sink - no need to buy bottled water, and it makes great coffee.

Russ

 

[ScrewyBrewer]

I’ve been using my RO filter weekly for nearly five years now. Using it for everything from brewing beer and coffee to watering the houseplants.

 

[KevinP]

Rgr that on the no DI.
The way my house is laid out, I can't get a line to my kitchen sink AND garage/brewery. The fridge shares a wall with the garage so brewery and fridge is doable.
The fridge would need to be supplied by a pressure tank yes?
Is it ok, once a month for brewing, to redirect the RO membrane away from the fridge pressure tank to fill brewing kettles? I assume yes but...

 

[Buckeye_Hydro]

Yes - would need a pressure tank to feed the fridge, and then another outlet (from the pressure tank or not) that would go to the garage for brewing. This is not an uncommon configuration.

Russ

 

[milldoggy]

Can you elaborate why no DI?

 

[Buckeye_Hydro]

A working RO membrane will get the TDS levels down to 5% or less of whatever is in the feedwater. So if your feedwater is 193 ppm TDS, your permeate (RO water) should be (0.05 x 193=) 9.7, or about 10 ppm TDS. For most brewers, that's "close enough" and zeros can be entered across the board into the brewing software programs.

If you want to make that 10 ppm permeate -> 0 ppm, you'd send it through DI resin. In this hobby, very few people go this route.

Russ

 

[fun4stuff]

Great to see all the interest in RO - it is a cool technology/piece of equipment!

A few comments on the content of the guide:

In general, folks new to RO place too much emphasis on the "more is better" line of thinking. For a typical RO with an atmospheric tank treating chlorinated water, think of a 3 stage as your default configuration:
Sediment filter->carbon block->RO membrane

If you want a pressurized storage tank, you'll need to add a fourth stage - a "Taste and Odor Filter."

If your tap water contains chloramines, you'll want an additional. high end carbon prefilter.


It is the capacity of your RO membrane that drives the speed at which purified water will be produced. Realize that unless you provide factory spec conditions, you won't get the full production out of a membrane. The two most important factors in temps of speed of production are water pressure, and water temperature. The best residential-scale membranes in the US are made by (DOW) Filmtec. They are spec'ed at 77 degrees F and 50 psi. Other brands are typically spec'ed at 60 psi or 65 psi and 77F. Colder water and or lower water temperature will slow production. How much? We have a calculator for that here: Reverse Osmosis Drinking Water System | RODI Systems | Home Water Filtration System - Buckeye Hydro


Regarding prefilters - The diagram shows the use of GAC as a prefilter - this is to be avoided. A carbon block will typically offer much better performance. If you see standard GAC used as a prefilter I'd question the expertise of the vendor - it is typically used because of it's low cost, not because of its optimum functionality. Carbon blocks are only very marginally more expensive.

Regarding the position of your "Probe 2" on the inline TDS meter, a better location for that probe would be BEFORE the Taste and Odor Filter as the RO water will pick up TDS going through that carbon filter.

Realize that the TDS of your RO water needs to be measured with the pressure tank valve CLOSED if your goal is to evaluate the condition of your RO membrane. Also be aware that the TDS of your RO water tells you nothing about the condition of your prefilters or when to change them. The answer to our first FAQ ("When should I change my filters?") addresses this issue in detail, here: Reverse Osmosis Filters | RODI Systems | Commerical Water Filtration System - Buckeye Hydro

Russ

can i use something like this as both a sediment and carbon filter (to remove sediment and chlorine)?

Aquaboon Coconut Shell Water Filter Cartridge | Activated Carbon Block CTO | Universal 5 Micron 10 inch Cartridge | Compatible with DWC30001, WFPFC8002, FXWTC, WHEF-WHWC, WHKF-WHWC 6-PACK https://www.amazon.com/dp/B01LYBM876/ref=cm_sw_r_cp_api_glt_fabc_6BGWK92BG6KCCZY3CW40

 

[Buckeye_Hydro]

Can you? Yes.
Should you? Probably not.

The primary purposes of carbon blocks are to treat chlorine/chloramine, organics, and taste and odor. To be effective they should be kept free of sediment. This is accomplished by using a sediment filter ahead of the carbon block. 1 Micron Depth Sediment Cartridge - Buckeye Hydro

 

[fun4stuff]

Can you? Yes.
Should you? Probably not.

The primary purposes of carbon blocks are to treat chlorine/chloramine, organics, and taste and odor. To be effective they should be kept free of sediment. This is accomplished by using a sediment filter ahead of the carbon block. 1 Micron Depth Sediment Cartridge - Buckeye Hydro

Thanks!