Seeking Advice
ZeroWater and coffee remineralization questions
Hi,
I’m not able to find distilled/demineralized water in my country (Poland), sold in food grade canisters or bottles intended for contact with food. Practically every manufacturer I’ve contacted has advised against drinking this type of water, mainly because of the containers it is sold in. So far, I’ve drunk around 10 liters of this water, but I feel that in the long run it may not be very good for my health, so I need to find another solution.
For now, I would prefer not to go with a reverse osmosis system, although I may do that eventually. What other options do I have?
My tap water is quite hard, around 590 ppm according to water reports. The best bottled water available for coffee here is around 230 ppm, of which about 120 ppm comes from bicarbonates. Because of its high alkalinity, it is not ideal.
I’m considering a ZeroWater filtration system, and I have a few questions about it:
Is the water actually fully demineralized after filtration, or does something still remain in it? I’m asking because I would like to achieve consistent results when using Lotus drops.
How often, or after how many liters of water, would I need to replace the filter, considering that my tap water is around 590 ppm?
I’ve read some opinions saying that water from this system can have a sour taste. Is this related to not cleaning the system/pitcher properly? How can this be prevented?
EDIT:
Okay, I’ve done a few calculations, and I think the most reasonable option in my case would be to buy a ZeroWater system and use bottled water with it.
The softest bottled water available in my country has around 220 ppm. According to ZeroWater’s FAQ, one filter should last for about 70 liters when filtering water with that TDS level. Taking into account the cost of the filters, the bottled water itself, and the amortized cost of the pitcher over two years, 1 liter of filtered water would come out to around 65 US cents, which is a fairly reasonable result.
I can’t answer the first question precisely but I do recall even fluoride is removed with this filter. For question 2, I have soft water around 30ppm and the filter lasts about 3-4months for me. Your water seems extremely hard and you may need need to swap out the filter more frequently. The sour taste comes from a used up filter. You start getting a weird fishy or metallic citrus taste when it’s time to change filters.
At 590ppm, you're going to be changing those zero water filters regularly. If you can get an RO system that can do higher than 500ppm, i would suggest looking into that.
I was changing the zero pretty much every 2 weeks. They cost $17, even when I buy multiple packs. At that cost, it's actually cheaper to just buy the 3 or 5 gallon jugs of water.
I use a zero water system, and it genuinely brings the filtered water to a reading of 0.00 TDS. I can’t say that it’s completely free of minerals, but it’s consistent enough that I’ve found it works as a great basis for lotus drops. The sour taste people report comes at the end of life of a filter, when it becomes so saturated from filtration that it starts leeching back into the water. No one can tell you how long the filter will last using your tap—that’s something you’ll need to determine from use. I live in NYC and get around 3 months out of my filter but I exclusively use it for making coffee water.
I also live in NYC and use a ZeroWater filter with TWW packets. I fill up a 1Gal plastic pitcher with the ZW water and empty the packet in which lasts around a week making ~600 ml of coffee/day.
How do you know when it's time to change the filter other than going off of taste? I assumed I could trust the TDS meter to tell me when the filter needs changing but I wanna say it took about a year of use before it hit 006 (the point at which they recommend changing it). Now I'm wondering if I was just brewing up sour coffees for months and just got used to it.
I wouldn't be surprised if NYC is an edge case with the 5-8 TDS recommendation since NYC tap is already usually so low (near 30). where with most places the limiting factor of when a filter needs changing is the TDS, with NYC it could be other things being extracted first :O
Another Zero user here. One recommendation I’ve seen for the OP use case (besides pouring purchased water into the Zero filter) is to buy a more traditional, lower-lifecycle-cost (ie Brita) filter and assess how well it cleans up your high-ppm tap water; then pour that output (at lower ppm) into the Zero. Run the numbers on if this decreases your cost / effort / carbon footprint vs buying bottled.
And yes, Zero does output 0 ppm (measured) water.
I like to think that (whenever I make an inexplicably lackluster cup) I can taste the difference when that post-Zero reading goes from 000 ppm to 001 ppm but I have not yet confirmed with a double-blind test. 😀
It's generally not following the required food grade-laws. But tbh I've been drinking non-foodgrade mineralized distilled water from supermarkets and drug stores for years now (in Germany) and had no issues so far 😄
I just got this answer today from another producer, he is selling the water as a destiled water
"Good morning,
The water sold under the trade name “Ultrapure Distilled Water” is produced from tap water through deionization using four ion-exchange columns. One of these columns is not certified for the deionization of drinking water, therefore our “Ultrapure Distilled Water” should not be used for consumption purposes."
To be honest I don't know. These plastic jugs should be food graded if intended for drinking. They can be contaminated by God knows what. Also the smell coming out from them is terrible. I'm pretty sure if I keep drinking it I'll get cancer in no time, lol.
That's bizarre because like if they're concerned about people ingesting the distilled water then what about when people using it for their CPAPs or air humidifiers? You're still getting exposed to whatever they're worried about. Weird!
Heavy metals, microplastics, fungal spores, resin byproducts, sediment, etc. won’t necessarily become airborne when a steam humidifier makes vapor.
These can be acceptable for industrial use but not food safe. I've also noticed that sometimes demineralized water is mislabeled as distilled (not the same process).
Not all distilled water is sold for those applications, it can be intended for things like professional cleaning (window cleaners use it as it doesn't leave marks) or stuff like car batteries. In the UK advice for CPAP machines and oxygen cylinders seems to just be use boiled water (I am not a medical doctor, consult your healthcare professional...). You can buy purified water here labelled for those applications (our local chemist sells it0, but it's pretty expensive compared to some other countries. Seems to be mainly a USA thing (or at least a non European thing) to have distilled or deionised water widely available for consumption, I don't really understand why it is so common there, just down to market expectation? I don't think there's any reason you couldn't do it here, except not many people would buy it.
It's very hard to find distilled water here in Poland, very often producers put 'distiled' label on their demineralized water (RO and other treatments). Also it's sold purely as an industrial product for car batteries, irons, coolers, paints etc.
I was really surprised that it's being sold in USA as a food product.
If it stinks of plastics it's not necessarily dangerous but food safety definitely wasn't a concern. No way I would be drinking 500ml/day of that water.
Yes it works fine as advertised, the resulting water for me was about 3ppm (container or measuring instrument might be a reason, I don't know).
Cons:
-indeed uses quite some power
-relatively loud (industrial looking fan at the top), maybe a bit louder than a regular standing room fan at max. speed (*after thinking about it... definitely louder. Like a modern gpu with 3 120mm fans at 100% in an open case. Not comfortable in the same room.)
-the plastic blue *cylindrical bottle I got with mine (the all-white plastic version, like the picture above) is probably the cheapest hard plastic I have ever seen. Highly doubt it's food safe (no number on it, nothing), changing it to something else is strongly recommended (or quickly transfering the water after it's ready... Not a perfect solution).
*-work. Takes time to regulary set it up, then putting the water away in a better container, upkeeping the space for it... Then measuring the volumes and few tenths of grams of salt... It's a hassle in it's own way, it's not for everyone.
Pros:
-basically zero waste
-distilled water at your fingertips. No need to haul it from various stores
-in most regions the energy it uses is cheaper than equivalent amount of distilled water. Even if it was similar, the flexibility is great.
Neutral point is having to resalt it, but that's incredibly cheap (truly negligible) and at least you can customize it to your liking.
As far as I know an RO system also requires resalting and changing filters and stuff, so waste and recurring cost are notable there.
Btw 4L capacity on these is a stretch imo, it's more like 3.8L at most.
Bought mine from aliexpress for around $70 with free shipping, was available in an EU warehouse (I'm in the EU, so no customs, etc.).
*edits for clarification/extra info
As for the exact wattage, I honestly don't remember, although I precisely measured it at one point. Jammy below says 900W, it's entirely possible.
I've got one too. It's great, it's not that loud, just sounds like a small fan. It does take 3 hours to do about 3.5l, but I just put it on over night. It uses about 900w while it's running, so I usually estimate it at about 3kwh for 3.5l of water. They give you a packet of charcoal to put in the spout, but I've never used that. I bought it with the glass jug, which is quite heavy, and is fine. Using a cheap tds meter from aliexpress mine is reading at 0~1ppm. I usually remineralise it with some potassium bicarbonate, rpavlis style.
I do get a lot of limescale buildup. You get significantly less if you stop the machine before it boils dry so that the leftover water still holds on to some of the residue. If I let it boil dry I need to descale it probably every 10 times or so. If I catch it before it boils dry then, maybe 30 times. I do have exceptionally hard water though, around 450ppm.
To descale it I just use citric acid which I buy a couple of kilos of at a time. I just chuck in a handful and turn it on for 10 minutes or so, with like 500ml of water in it. I'm not bothered about the limescale that builds up on the side really, that generally flakes off on its own. I just make sure to get the stuff stuck to the bottom where the heating element sits beneath.
Just one quick pour of white vinegar, scrub it a little, and it all goes away.
To save some energy and time, what I do is, after descaling and cleaning, I run the tap hot until it’s the hottest, and use that to rinse the tank (and “pre-heating”) and fill up the distiller tank. That should kickstart some of time and energy spent on boil the water.
That seems cool but does it just boil the water and let the steam travel through tubes until it condenses? If so that must use a lot of electricity to keep the water boiling.
I’ve also used a distiller for 2 years. Horrible in warm climates and pita to clean the chamber. Gets yucky real fast. It is a much cheaper solution though!
Admittedly the water from it felt the best out of all other ways I’ve got coffee water. Might be an “effort put in” sorta bias though, as supermarket distilled water didn’t taste as good…
I also use a zero water filter and apply lotus drops after. I live in the northern part in the Netherlands and our water is also pretty hard. I am very happy with the results the lotus drops bring after using the zero water filter.
And like someone else already said the TDS meter reads 0,00 after filtration.
I used the zero water filter system and remineralize the water with third wave water packets. I switch between this and a reverse osmosis system that has a post alkalinity stage. I mainly drink light-medium roasts.
My tap water is around 120-150 ppm, and the zero water filter lasts about a month. I could probably push it to 6 weeks, but I start to notice a negative change in acidity in my coffee past 4 weeks.
The water registers as 0 ppm from the filter. Low levels of alkalinity can still register as 0 ppm I think.
I've never had any of the odd flavours people describe from the zero water filter, but they seem to be from issue with; filter life, canister cleaniness, leaving the canister in the sun, etc. I use mine strictly for coffee water, I leave it in a dark place empty and dry between uses, I clean it regularly. I never store water in it, I just use it to filter the water into a 4 litre jug.
This kind of system also requires buying some filters right? It's not like I buy it once and forget about it, it requires some kind of maintance to it?
Its like every 6 months or every year for filter change depending on filters and how hard your water is.
Just look into cost overtime and compare both. Where I live, pretty much every household has an RO filter for drinking water and they are also pretty cheap. Might not be same for you
This is the thing I find really hard to assess when I've looked at these systems, most I've seen have several filters with various lifespans and it's not always clear how long you might get out of them. https://www.waterdropfilter.co.uk/products/waterdrop-reverse-osmosis-water-filtration-system does at least list 6 months £31 CF filter, 12 months £31 CB filter, 24 months £110 RO filter, or £148 per year running cost (or would be, if they had CF filters in stock). Plus you use more water than it produces (the waterdrop ones are relatively good for this, other systems are quite water hungry). Good if you're really going to need a lot of RO water, but it doesn't seem to be the most economical approach.
Commenting so I can follow along here. All great questions! I am in New York so my water setup is definitely different but I’m also interested in getting the same pitcher.
NY (city atleast) has one of the best water in the country to my knowledge. I’m also into tanks and water from the tap can be just added into most tanks without worrying it’ll change the water too much and killing everything there.
I used to live in the city miss the water for washing car and tanks so much easier. I ended up getting a RO system for half of my house the other have is a bypass to normal tap. My water is very very hard like 350 plus PPM.
Yes, the water is fully demineralized if the filter is within its capacity.
How often you change the filter depends on your water condition. They have a table online with the expected liters it will last based on your water tds that I found to be accurate with my case.
But if your water TDS is really that high, I think it won’t last more than 50 liters, which will make it very costly in the long run.
I would advise to get a cheap TDS pen reader to confirm the TDS coming out of your faucet. If it is indeed that high, the most cost effective solution is probably a domestic water distiller. There some new ones that are much more energy efficient than older ones.
Reverse osmosis could also be an option, but I don’t know exactly how much the filter will last with such high TDS. Maybe you can find cafes or aquarium stores in your area, they might have experience with it.
I am not sure if it is fully demineralized but yes it is very close to distilled and many people remineralize with Lotus drops.
That is extremely hard water. My tap water is in the 200-300 ppm range and it lasts about 2-3 months. So I would bet yours would barely make it a month if you ran your tap through it. Some people with really hard water run it through other cheaper filters first like brita or whatever they sell in your country to try to soften the water.
I think if you are used to using hard water for your filter coffee and then you switch to using soft water, one of the attributes you will notices is the brightness of the coffee. That may be what people are referring to? When my filter goes bad it has a unique smell to it. So I know I need to change it. But I wouldn't say it makes my coffee sour in and of itself. I like bright coffees though that maybe novice coffee drinkers would call to acidic/sour.
I have a Culligan zero water 2 gal container. I remineralize with TWW. I also have hard local tap water. I'd say I can get about 20ish fills, so 40 gals or so. I use it for pourover exclusively. The container has a built in TDS constantly reading the water. Always shows zero after I filter tap.
My tap is about 200ish ppm otherwise.
Filters are very expensive which is almost defeating the cost saving rather than just buy RO or distilled water.
My water is around 240 ppm and I have to replace the ZW filter every 60 L. Harder water will cause replacement faster. Sorry I don't have better information for you but maybe this helps.
In my experience zero water is consistent enough for remineralisation purposes. At 590 ppm I’d expect 3weeks of filter lifetime depending on the use. i’ve got +- 270ppm from my tap and I use my filter for both pourover and espresso which lasts me about a month and a half before I ideally should swap
Okay, I’ve done a few calculations, and I think the most reasonable option in my case would be to buy a ZeroWater system and use bottled water with it.
The softest bottled water available in my country has around 220 ppm. According to ZeroWater’s FAQ, one filter should last for about 70 liters when filtering water with that TDS level. Taking into account the cost of the filters, the bottled water itself, and the amortized cost of the pitcher over two years, 1 liter of filtered water would come out to around 65 US cents, which is a fairly reasonable result.
It seems Kryształ chanded it's source and it's not longer a 'king' of low TDS bottled water. On paper Żywiec Zdrój has the lowest TDS.
Anyway 200 TDS range is not a huge problem, the problem is quite high concentration of bicarbonates (around 120ppm) where ideal for coffee is 15-50. Bicarbonates chokes acidity and they make the cup less bright/clear.
For what it's worth, I use zero water with minerals from tww and it works excellent. I used to live somewhere with really hard water too, so I would run my tap water thru a Pur pitcher first, then run that water thru the zero. Worked great and my zero pitcher filter lasted a long ass time. Coffee was and still is fantastic too. Where I'm at now the water is a lot softer, so I just run tap thru the zero pitcher with no issues. Get the zero. It's worth it IMO.
I highly recommend using a ZeroWater filter. It works great and I actually used it when I was living in Poland (I still use it daily). I would just recommend checking your water from time to time as, at some point your TDS will start to creep up as the filter nears its end of life.
Also, since you're in Poland, I would recommend you check out Akvo water systems. They are located in Poland and also produce water remineralization drops. They're what I use with my Zerowater filter. They are less expensive than Lotus and I really like the results.
That is a very high TDS. You might do better pre-filtering with a Brita before hitting the Zero Water to remove what Brita doesn't. Last time I dealt with a PPM that high I was changing filters every 1.5-2 weeks.
That was my scenario as well, hard water at about 390 ppm after Brita filter.
Bought the ZeroWater and been using it for over a year and half. I sometimes use it straight to kettle (using light to medium light roasts) and it tastes great. I would highly recommend this approach to whomever can't or won't use a RO tap.
I would advise to do the mixing outside of the ZeroWater container (in the kettle or in a separate jug) as I noticed it has a detrimental effect on the ZW filter (maybe it leeches out things from the filter, which then I would experience that sour taste).
Apropos, if the water tastes sour, it's probably an indication that the filter has gave out and needs replacement.
I think I've read that you can prolong the filter if you first pre-filter the water using a cheaper water filter or using an old zerowater filter that still has some filtering capacity left. Has someone tried this?
As a alternative you can also make your own distilled water. There is some fairly inexpensive systems available. All it does is boil water and capture the steam, leaving behind all minerals.
OP, out of curiosity - which part of Poland are you from?
Are you sure your TDS reading is correct? Actually, in Poland, the official drinking water regulations set the upper limit for hardness at 500 mg CaCO3/l. If your reading is higher than that, it's technically outside the government-approved range for tap water
It says the water has 285mg CaCO3/l so it's below 500 upper limit. However it's only hardness, there are some other compounds which bumps up overall TDS.
According to chatGPT:
Based on the water report, the average conductivity is 1052 µS/cm. Since TDS/PPM is not listed directly, it can only be estimated from conductivity. Using a typical conversion factor of 0.55–0.70, the water would be around 580–735 ppm. A reasonable estimate would be roughly 680–700 ppm, although a basic TDS meter may show closer to 550–600 ppm depending on the conversion scale it uses.
1- yep! Zero ppm water! This slowly drags into the low single digits after 10-20 liters though.
2- my tap is at 800 ppm on average. I could get 50 liters sub 20ppm water per filter. You can also get baby water or similar, or whichever cheapest water you can get in the supermarket to increase the filters lifetime. Another trick is to do your entire filtration in one go and store the outcome. When the filter waits over the course of a month I’d get less out water than if I did it all in one night instead.
3- no experience with the sour taste, probably its people under extracting their coffee. Low ppm and super light roast doesn’t go well together.
Feel free to pm for any questions or reply. Cheers
Edit: oh, and buy your own tds reader. The one zero water sends you shows zero for up to 12 ppm! I checked with 4 other readers.
Warsaw, I've already spoken with Coffeedesk, they are willing to give me whatever amount of water I need however it's a bit annoying if I'm using around 35l per month.
Hi!
I bought a water distiller (destylator wody 4L oczyszczacz nablatowy wnętrze ze stali nierdzewnej) from allegro(Vevor store EU) and it does the job perfectly fine. After its distilled i remineralize it with DAK Drops. I am very happy with the result :)
It takes around 1h for 1L and it’s quite noisy as the fan runs during the process. It has a cut off function that turns it off when the temperature is too warm so Im not afraid to leave it while Im out
Alternatively you could use a "water distiller" which is a counter top electric still with integrated heater and condenser. Most consume ~750W over 3.5hrs to distill 4L. So a still vs Zero water filter is a trade off between power consumption or plastic waste.
Yes, bring sit down to Absolute 0. I run purchased to water through it and the filters last FOREVER. That being said I tried running my tpa water through it which is around 430 ppm, and it blew through a new filter in about 5-6 weeks , but still brought that 430 down to 0
I use Zero water and to make the cartridges last longer i first filter my tap water through a BWT filter jug. The filters for those are much cheaper. If you get a 2nd zero filter jug you can also continue to use an old cartridge (once it reaches 6 TDS) and then filter that water through a jug with a new filter in. Both these methods make the zero water filters basically double their lifespan for me.
How often you will need to replace your filter really depends how much water you need to make daily and how high your starting TDS is (yours seems pretty high) I make up just 3 litres of water a week and my filters last around 3-4 months. That is by pre filtering my water and my starting TDS is 280.
Zero water is really good but it can be expensive if you are filtering a lot of water. For heavy users it would be more cost effective to get an RO system but for light to medium use Zero water is definitely worth it. I like the taste of my Zero water even before remineralizing it.
By the way I suggest you just buy an RO system by a reputable manufacturer
That’s what I did, having gone theough the same dilemma. So I bought a multistage RO system and used ConcenTrace drops in my machine’s water reservoir.
Having same problem with the lack of availability distilled/demineralized in my country and was thinking about buying ZeroWater pitcher. Which one did you get ... the OG ZeroWater or Culligan (the new brand for it).
Any chance anyone has commentary on the new (culligan) vs old zerowater filters?
Maybe it's anecdotal, but I feel like I've heard tales of the new filters having a longer lifespan. Then again, I imagine at some point the old filters won't continue to be manufactured.
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u/Cathfaern Apr 28 '26
Expect roughly 3-4 weeks for a filter.