Bitter aftertaste... it was my water filter and plumbing.

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

#1: Post by ShelbiRyan »

I'm posting this for those who have been battling a bitter after taste and are at their wits end of troubleshooting. If you have a plumbed in machine, all basic espresso brewing parameters have been beat to death and a bitter taste is still present, you may want to have a look at your carbon filter and plumbing.

I'll start from the beginning. My local cafe is only a few blocks away, so for me to compare drinks was relatively easy. On top of that, I also have a coffee subscription with them and they happen to share their brewing parameters. I would match things identically, pull a shop, taste it and walk over to the cafe for one of theirs. The difference was undeniable, something was very wrong with my coffee and had been for quite sometime. After exhausting every dose, yield, temp and coffee combination imaginable I was down to water. I retested my TDS, PH, alkalinity and calcium hardness. Nothing was out of whack. I emailed the cafe and asked to compare water test results, they were happy to. Yet again, nothing stood out. At this point they were nice enough to lend me a jug of their water. I flushed out my machine and used my onboard tank to compare water with my plumbed in filtration system. Low and behold....the bitterness was gone!!! I switched my machine back to my filtration, flushed, and as predicted...the taste was back! I did this 3 times to verify. What gives!??

I changed all my water filters, topped up my softener, flushed and retested. Still the same bitter taste. I then went as far as removing my current filtration system and purchasing the same one as my local cafe. PROBLEM SOLVED! My coffee for the next 3 mornings was absolutely glorious.....until the taste came back...

My apologies for the long post, I'll get right to the point from here. With help from a local barista we discovered that my carbon filter was being ruptured internally and bypassing bitter tasting water (from the carbon) into my machine. The issue was that I had tee'd off of my cold water tap into my filtration system. Whenever the cold water tap in my kitchen sink was turned on and off two things would happen.
1 - It would draw water back out of my filtration system (like a Venturi) when my sink tap was on.
2 - Cause a pressure spike when it was slammed shut.

Our theory was that this was causing the filter to internally rupture and leach carbon into the water.

How I fixed this was by adding a one way check valve off of the tee and into my filtration system. I also moved my pressure regulator before the filters instead of after. I then replaced my filter again and my coffee has been superb for almost two weeks now.

I would assume a lot of you know about these things or have experienced similar problems. For those who don't, I hope this post will help!


#2: Post by Cerberus »

I'm waiting for my water filtration system to arrive in the next week or so (looking to buy the system that Clive Coffee sells). I follow what you did, but could you share a pic of your setup? I'm not a plumber, but it seems easy to install; however, I rather not go through the installation process twice... Thanks!

Prescott CR

#3: Post by Prescott CR »

First off- good job and perseverance!

That's both crazy and makes sense all at the same time. Thanks for sharing that resolution. There are already so many variables that we have to consider and control with espresso and the filter blowing out isn't one that automatically comes to mind!

Were there any signs of carbon particles? For example from steaming or a hot water spout? I can see where one would think they were espresso grounds if there were.

Thanks again for sharing this, no doubt it doesn't happen often but when it does this will be helpful!

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#4: Post by danetrainer »

Thank you for your detailed post and well done on getting to the root of your water problem.

In a minor way I just went through a similar period where my espresso was not tasting as it should. At home I have some of the best water right from my tap and I am plumbed in with no filtration system required.

I'm away for two months and brought my own roasts, my Robot and Kinu grinder, I ran out of water I brought along, my go-to water to buy is Crystal Geyser from the Weed California source, but now being in the Southeast I can no longer get that source & tried around 4-5 other " bottled at the source" spring waters. My Espresso was sometimes bitter or sour, eventually I found some CG from the Blue Ridge Mountains and it's back tasting how it should.

This is just a good reminder to not automatically blame the roast, the equipment or your procedure when your coffee isn't tasting as it should.


#5: Post by wachuko »

Great information!! Thank you for sharing.

I have mine plumbed the same way (T off cold line from sink)... looks like I will be ordering a check valve as well.

I also ordered sediment filters to place before and after the main filter. I have the Bestmax filter that I got from WLL...

I do not have a water softener in this house, so that filter is all that I have...
Searching for that perfect espresso!

Wachuko - LMWDP #654


#6: Post by wachuko »

Also, as mentioned, if you can share the setup you have... that would be great.
Searching for that perfect espresso!

Wachuko - LMWDP #654

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#7: Post by Nick111 »

Congratulations for persisting in finding the reason.
Very helpful information.Thank you for sharing.

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#8: Post by Peppersass »

The check valve makes sense for your installation, but normally isn't needed for installations with a separate input feed.

From what I can tell online, the pressure rating of carbon filters ranges from 4-10 BAR (58-145), depending on brand and model. I've seen some good ones in the 6-7 BAR range (90-100 psi.) So the location of the regulator depends on your supply pressure. If it's higher than the filter rating you have to put the regulator before the filter. If not, and the filtration system has sufficient headroom, it may work better to put it after the filtration system.'

I would guess that unless your water source has very high pressure the main problem was the water slam and back-pressure from the sink tee.

FWIW, I have my regulator after the filtration system because 1) my well system produces a max of 70 psi, 2) I use a commercial filtration system, 3) I tried putting a regulator before the filtration system and there was too much pressure fluctuation in the well system, 4) My filtration system is in the basement about 8 feet below the machine, so my gear pump has to work a lot harder if pressure is dropped too far downstream, and 5) I sometimes use the regulator to set a low flow rate for flow profiling so it has to be near the machine.


#9: Post by Cerberus »

I suppose putting backflow preventer would be in line with Jim's (1st-line Equipment) plumbing recommendations.


#10: Post by wachuko »

I went ahead and ordered this one... easy to cut the tube and insert inline...

Image ... 337&sr=8-6
Searching for that perfect espresso!

Wachuko - LMWDP #654