Chicago Suburbs and astringency

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

#1: Post by Chingachgook »

Let me preface this by saying I would consider myself a seasoned enthusiast. I've been brewing and home roasting for four years. My goal remains unchanged : enjoying the craft and drinking good coffee. I'm always eager to learn but I wouldn't call myself an avid tinkerer either. Hence why I still don't own a TDS meter.. I know, I really should... :oops:

I recently moved house and have been stumped by problematic pour over and Moka brews. Everything has been incredibly sour. My previous home was in an area known for very hard water but the house had an RO system in the basement. In my new place I've been using straight tap water, with no RO system. The water here seems fairly soft by my standards, based on the city water report there's obviously mineral content but I have no problems with deposit buildup on dishes, etc.

I tried purchasing RO water from Whole Foods, but same problem; incredibly sour light roasts, lesser so with dark roasts but still noticeable. I use a stovetop hario kettle, if that's useful information. Finally, I tried a MUCH finer grind on the Niche -- finer than I've ever attempted for pour over. It was a slow brew - about 4 minutes but the results were SO much better. It still lacks a certain mouthfeel that I am accustomed to, but maybe I'm used to brewing with really, really hard water? My only other thought pertains to a botched roast and better water shining light on that.

pham

#2: Post by pham »

I'm based out of the chicago suburbs. My suburb gets lake michigan water, which is quite good on tap for drinking but is not amazing (but not horrid) for coffee. For very light roasts, it's quite dull and muddy.

If you used to live in a very hard water area, chances are your RO system was working to a level which suited your roast profiles. Here, the GH and KH are around 100ppm as CaCO3 (the two most relevant stats for coffee extraction) so an RO system will take that down much closer to zero, and hence, thin and sour coffee. I bring my water down to 0TDS and remineralize myself using magnesium/calcium salts along with baking soda to add buffer. Water is extremely important so controlling the composition is annoying, but very necessary for good coffee.

If you are willing to remineralize yourself, I recommend having a GH between 40-80ppm CaCO3, and a KH between 20-60ppm CaCO3. Otherwise, I'd add some tap water bypass to your RO system until the TDS meter reads between 40-90 TDS and your coffee tastes good.

TallDan

#3: Post by TallDan »

Which suburbs are the two of you in? I'm in Northbrook, and our water is sourced directly from Lake Michigan, I believe it's the only suburb that does not have any Lake Michigan shoreline that directly pumps and processes it's own water from the lake. I've recently switched from mineralizing distilled water to mixing one part tap water with two parts RO water from whole foods for my espresso machine. I chose that ratio based on the results of a water sample test that I had done a couple of years ago.

Chingachgook (original poster)

#4: Post by Chingachgook (original poster) »

TallDan wrote:Which suburbs are the two of you in? I'm in Northbrook, and our water is sourced directly from Lake Michigan, I believe it's the only suburb that does not have any Lake Michigan shoreline that directly pumps and processes it's own water from the lake. I've recently switched from mineralizing distilled water to mixing one part tap water with two parts RO water from whole foods for my espresso machine. I chose that ratio based on the results of a water sample test that I had done a couple of years ago.
I moved from Barrington to the Dundee area - I thought South Barrington used Lake Michigan water but I know for a fact Barrington has pumping stations. Interesting idea to mix RO and tap, I may give that a go. I'm grinding finer than what should be necessary to get drinkable results and it's still thin.
pham wrote:I bring my water down to 0TDS and remineralize myself using magnesium/calcium salts along with baking soda to add buffer.
If you are willing to remineralize yourself, I recommend having a GH between 40-80ppm CaCO3, and a KH between 20-60ppm CaCO3. Otherwise, I'd add some tap water bypass to your RO system until the TDS meter reads between 40-90 TDS and your coffee tastes good.
I'm curious, which method do you employ for remineralization?

pham

#5: Post by pham »

I remineralize by making concentrates of CaCl2, MgCl2 and KHCO3 that correspond to 1L batches per this article https://awasteof.coffee/how-to/mixing-water/ (My consumption isn't super high) and I manually remin my water whenever I make it. Not super convenient but I love the coffee that I drink

TallDan

#6: Post by TallDan »

Based on some quick searches, it looks like Dundee and Barrington both draw water from their own municipal wells, so no surprise if the water is significantly different. The Dundee water report that I found only covers contaminants and not mineral content, so you may want to contact them to see if they have water analysis that covers mineral content. I wouldn't necessarily expect a useful response, they may not have or may not publish that information.

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another_jim
Team HB

#7: Post by another_jim »

It may be a question of consistency and stability. If you want stable extractions, use water that reads 75 ppm TDS or higher, grind fine, brew long, with water that is not too hot. That will create a brew that has asymptoted to the highest extraction yield possible; and that is therefore stable and easily repeatable.

The problem is that lighter roasts can taste dull at this maximum extraction asymptote. With such roasts, you are chasing an unstable extraction point for the best tasting brew or shot. Small variations in water composition, grind, or brew temperature will create big taste variations and big disappointments.

If this is what is happening, I humbly advise changing your coffee, not your water. Life is too short to chase after coffees whose best taste requires hitting an unstable point in the extraction phase space.
Jim Schulman