BWT Bestmax Premium filter not working as expected

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.

#1: Post by IridiumBlackberry »

Hey alll,

Having some troubles with my water filter from BWT. About a week ago I decided I wanted to go the plumb in route for my espresso machine. After reading online and watching some videos I thought that BWTs bestmax premium should fit my needs. Since I'm Berlin Igermant I also decided to purchase a flow meter so I'm always sure of when to change my filter.

After I installed everything, I check my TDS with a HM tds meter and noticed that the tds was only 220ppm from 320ppm which Berlin water is normally at. I was honestly a bit disappointed here as the bypass is on 1 which is the lowest I can go. I've been mostly mixing my own water up to this point so that now double from what I'm used to. As a result I decided to hold off on hooking up to the machine and decided to trail it with my filter brews. Initially I was somewhat impressed with the flavour. Taste seemed to be good whilst having no dirty taste that you get from having to much hardness in the water. Fast forward to a week later when I was having another hand brew, this time it tasted horrible. At this point we hadn't hooked up the filter to the machine but we're using the water out of the tap. My wife also noticed the bad taste. I decided then also to buy a dGH and dKH test kit. From that kit I noticed that readings were 8dKH and 13dGH which is 1 point down from the Berlin tap water!!! That equates to around 142ppm for calcium hardness. Way too high for a machine.

But it gets more bizarre, after another day I decided to retest the water. I then obtained a reading of 3dKH and 7dGH. That's half! Wtf! I then decided to fill my espresso tank with the water which is around 2 lifers. Just to be sure not to report myself from the other day I retested it again with the kits. It now jumped up to 8dKH and 13dGH again. What the heck is going on with this filter!!!

Having the worst experience with this plumped solution. Kinda sucks too since I dropped around 300 euros with the filter and a new 3 way tap just accommodate it!

If anyone is familiar with BWT and their systems I would greatly appreciate it if someone could help me troubleshoot this issue.


#2: Post by palica »

Did you test tap water as well, to check if there are fluctuations?
Also, there is a bypass position 0 on BWT heads (so no bypass: all the water is filtered and descaled, instead of all filtered and some descaled).
Is the filter new? Did you completely flush it after installation?
Also, did you communicate with BWT hot line? They may have suggestion as well.

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BaristaBoy E61

#3: Post by BaristaBoy E61 »

palica wrote:Did you completely flush it after installation?

You might have to flush more than you already have done.
Unless you're using a lot of filtered water it's best to buy the smallest size filter as it will expire well before it has exhausted its capacity.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

IridiumBlackberry (original poster)

#4: Post by IridiumBlackberry (original poster) »

Ok, I was not aware that they have a 0 setting. Perhaps I'll try this.

Regarding testing the tap water. I was testing that as well as the treated water. The tap water results were quite stable.

I have the "S" size, BWT recommended flush was 1L I think. Initially I flushed 3L. Plus also it's been a week of use, shouldn't it have stabilised by now?

I have reached out to BWT but I'm still waiting on a response.

Do these filters have a max flow in a given time window? I.e. no more than 1L in 5min?

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BaristaBoy E61

#5: Post by BaristaBoy E61 »

IridiumBlackberry wrote:I have the "S" size, BWT recommended flush was 1L I think. Initially I flushed 3L

It's good that you purchased the smallest size. Installation instructions indicate "Minimum Flushing of 1L" & "After a break in operation exceeding two days, the filter system must be flushed with a minimum of 4-5 litres of water."

Try flushing some more and do a cold water taste test by drawing water from the filter head straw (Best Max Flex Head) refrigerate and taste test by drinking a glass to see how it tastes and compares to straight tap water taste.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

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#6: Post by kolu »

Hey there mate, you say Berlin? BWT Bestmax premium is as far as you can get taste-wise without going for RO. Berlin water has really high sulphates content so problem with most decarbonisation filters (Bestmax) is the precipitation of gypsum. The only way to prevent that is RO or using water softener (Bestprotect for example - but the taste isn't great).
Be careful to measure your water alkalinity (temporary hardness, KH) and set your bypass according to that otherwise your water will still be able to deposit gypsum but will be corrosively acidic as well. From my memory water in most parts of the Berlin was averaging 11-13 dKH, suggesting bypass setting of 2 as optimal. General hardness though is very high in most places, around 16-20 dGH.
Also, measuring tds with conductivity meter is useless and tells you exactly nothing. Do not use conductivity meter reading as a basis of setting your bypass otherwise you will seriously damage your machine long-term. What it is good for is periodic checkup on the state of the filter - if your TDS increases around 30% from fresh it might be good to think about replacing your filter. Any other use is nonsense.
Furthermore the Bestmax Premium replaces some of the Ca ions for Mg that doesn't for insoluble gypsum deposits, so it can be used in your area (compared to Bestmax filters that we have actively avoided just because of this issue) but still beware of setting the bypass too low and causing corrosion damage to your machine.

For record - I was working for 3.5 years as coffee machine tech in Berlin for die Espressonisten...