Author Topic: The Water Saga  (Read 391 times)

Offline stevea

  • Standard User
  • **
  • Posts: 214
The Water Saga
« on: May 01, 2018, 02:09:39 PM »
In some ways this is probably not the right forum, nor quite the right topic area for this , but ....

I've been experimenting with water wrt making drip coffee.

I've been starting with common RO water, which is nearly de-ionized (<2ppm of anything soluble) then adding ions and comparing the flavors. of the result.  I've been playing with ...
<table salt, baking soda, epsom salt, gypsum, chalk, lime (slaked), calcium chloride, magnesium chloride, lye>
aka
<sodium chloride, sodium bicarbonate, magnesium sulfate heptahydrate, calcium sulfate dihydrate, calcium carbonate, pickling lime, calcium chloride anhydrous, Mg.Cl2-hexahydate, , sodium hydroxide>

I was motivated by the SCAA guideline, and a paper describing "70/30" water which references a paper on calcium vs magnesium in coffee extraction.

(sorry for the column shifting, but here I've added milliMols to the SCAA fields, tho microMols (uM) are more appropriate.

SCAA guidelines   Characteristic   Target   Acceptable Range   comments   
   Odor   Clean / Fresh, Odor free      Duh!   
   Color   Clear color                         Duh!   
   Total Chlorine   0 mg/L                     Duh!   
   TDS   150 mg/L   75 - 250 mg/L      
   Calcium Hardness   68 mg/L   17 mg/L - 85 mg/L   0.68 mmol Ca ions (0.17 - 0.85)   
      or 4 grains   or 1 - 5 grains      
   Total Alkalinity   40 mg/L   At or near 40 mg/L   0.40 mmol X.CO3   0.80 mmol @pH7
   pH   7.0   6.5 to 7.5                         Meh!   
   Sodium   10 mg/L   at or near 10mg/L   0.435 mmol Na
--
The SCAA guideline has some very limited value IMO.   Clear, odorless, w/o chlorine are pretty basic rules.   Then things go off the rails.  TDS(total dissolved solids) isn't a very important factor in flavor, so long as it's below some rather high threshold.  It's mostly a "don't care" unless you live on the dead sea.   Total alkalinity is a very important factor, as it represents the total amount of buffering that will neutralize coffee acids.   pH, within reason is also a "don't care".  The amount of ions necessary to push the pH of pure water up&down is a tiny fraction(<1%) of that needed to overcome the buffering in the stated alkalinity range.   Their requirement for sodium near 435 uM is also questionable; as I'll note below.

So I mixed up reference solutions of the items on my list above, and I've been using a syringe pippette to add calculated/measured amounts to the 1.24 liter Breville Precision pot w/ 69 grams of groundsthen tasting the results.  I've been at this most of 3 months now.
===

W/o a lot of explanation I'll recite my personal findings.

Pure RO water - produces a relatively harsh and acidic cup.  Not good, tho' certainly not horrible.

Alkalinity - I won't digress into a water chemistry talk, but numerous anions contribute to alkalinity.  Most notably the species of carbonate/bicarbonate.   Combined with a divalent cation (calcium or magnesium for our purposes) this forms "temporary hardness and "lime"/chalk that is the bane of boilers.  Among alternatives - we can use a mono-valent cation (like sodium carbonate) for alkalinity and avoid the "chalking" problem, but frankly we want the divalent cation to make good coffee.   There are other anions that provide alkalinity - notably hydroxides (like sodium hydroxide and phosphates).   In my experience a water alkalinity around 750-850 uMev of alkalinity is perfect for most coffee.   The one parameter SCAA nailed.


Among the cations ....

Sodium - this IS the 'saltiness' factor in table salt (taste some baking soda for comparison).   My personal opinion is that the SCAA recommended 435uM of sodium is a reasonable compromise, but values from 200uM to 650uM are quite acceptable.  Values much above 800uM are beginning to taste like "Phoenix coffee" or "Bay Area coffee - saline.

Potassium - I didn't try potassium in any of these experiments, but from winemaking my opinion is that it's similat to sodium salts, but decidedly more bitter (in a bad way).

Calcium - is one of the two bi-valent ions available (Mg Magnesium is the other) and does allow proper flavor exrtaction and enhances any creamy, smooth characteristics to ~400uM.  Then it gets "chalky".

Magnesium - it is claimed should do a better job than calcium in extracting flavor components and also provides that creamy sensation.  In side-by-side comparisons I can smell the difference between the calcium vs magnesium coffee (magnesium generally better).  There are two downsides to magnesium. I accidental made an Italian roast (yeah I know) and extra magnesium REALLY accentuates the burnt notes.  Too much magnesium provides an odd bitter/sour note, and this seems to happen above 250uM and becomes fairly unpleasant around 400-500uM.

Among the anions ...

Carbonate - is the common alkaline buffer in most tap water, and the acidified carbonates disappears as CO2 (leaving no discernible taste) but excess residual carbonate in the cup tastes "chalky", esp in combination with divalent cations.

Hydroxide - requires about twice as many mols as carbonate to create the same amount of acid buffering (at reasonable pH values),  So tho' flavorless, we have to consider the matching cation concentrations.   For example getting 800uMev of alkalinity from sodium hydroxide means adding 800uM of sodium - which IS pushing the limits.  Slaked lime, calcium hydroxide (Ca.(OH)2) however adds ~400uM of Calcium for 800uMev of alkalinity and works very well flavor-wise.

Sulfate - often added to brewing water as epsom salts, in modest amount is a perfectly fine addition, however above ~ 200-250uM it begins to display a flat-dry 'taste' on the surface of the mouth (which isn't completly foreign to coffe)..  Ideally kept <180uM IMO.

Chloride (Cl-) - this one is really peculiar and hard to pin-point.  In small amounts it's great, but in excess provides a brackish-harsh seawater note.  It *seems* to accentuate the saltiness of sodium - so Na+Cl gets bad-salty a bit faster than sodium carbonate.  It also exaggerates the bitterness of magnesium in a more dramatic way.  250uM is quite acceptable, even with a lot of sodium (say 800ppm).   Hard to spec any upper bound except in reference to other ions.

Phosphate - I didn't try any phosphates in these experiments, but I think they actually may be promising given their alkalinity and flavor profile.


====

"70/30 water" - https://s3-ap-southeast-2.amazonaws.com/hosted.fivesenses.com.au/hosted_docs/water_recipe.pdf

This is actually a pretty good coffee-water.  Excellent aroma extraction and enough divalent cation for the good creamy sensation.   OTOH I find that it has a little bit too much sulfate ion, and by comparison produces a modest flat-dry mouth-feel.  One way to improve this (IMO) is to replace about 1/3rd to 1/2 of the epsom salt ions with Magnesium chloride ions.  This reduces the sulfates from ~250uM to toward 120-170uM, without adding too much chloride.

===

Another water I enjoy using  as 380 uM of slaked lime for alkalinity (with calcium) and 200uM of Magnesium Chloride.(this is pushing the chloride limit IMO).  Or switch out some Chloride for Sulfate as above.

A recipe for a liter involves 28mg of Ca(OH)2, and 40mg of Mg.Cl2.6H2O (the common hydrate) [Note lime is only marginally soluble in water, so you can't make a highly concentrated verion of this.

===

Third-wave water.

https://prima-coffee.com/equipment/third-wave-water/third-wave-water?gclid=CjwKCAjwoKDXBRAAEiwA4xnqv8-5Uel5HBjxDtVvIStcqesAlJ4UTEmqQ4nXL9Z7mdg5efk3LwLHdRoCMmwQAvD_BwE

I have not tried this, but if the written reports are correct is has WAY WAY too much sulfate for my taste, and costs about 50 times more than I'd be willing to pay for a pinch of basic chemicals.

===

Designing a great water is rather difficult due to the limited solubility of various salts ...

http://bluevision.us/solubility-chart/sample-solubility-chart-template-7-free-documents-download-in-intended-for-solubility-chart

For safety & flavor reasons we are primarily limited to the columns labelled Na, K, Mg, Ca and the rows labelled Cl, OH, SO4, CO3, and PO4  and ChCO3(acetate).

It's trivial at increase the amount of sodium, (or the less desirable potassium).  It's hard to get magnesium & calcium we''d prefer without a load of chloride or carbonates or sulfates  we'd like to limit.

Some like Magnesium hydroxide would be a great chem for water adjustment (magnesium + alkalinity), but it's not significantly soluble.  The soluble magnesium (or Ca) acetates look promising, except they have a slight vinegar smell and are probably flavor-problems in coffee.

I plan to keep 'experimenting', but aside from dissolving magnesium hydroxide in something like phosphoric acid and .... I'm running out of runway.


« Last Edit: May 01, 2018, 02:24:04 PM by stevea »
"Never put off until tomorrow what you can do the day after tomorrow."  Mark Twain

Offline stevea

  • Standard User
  • **
  • Posts: 214
Re: The Water Saga
« Reply #1 on: May 01, 2018, 02:28:06 PM »
Sorry - the other link to a solubility chart is rather variable.

Try rows<=>columns

https://en.wikipedia.org/wiki/Solubility_chart
"Never put off until tomorrow what you can do the day after tomorrow."  Mark Twain

Offline Ascholten

  • Distributor
  • *****
  • Posts: 7547
  • Artisian 6 and Behmor
Re: The Water Saga
« Reply #2 on: May 01, 2018, 02:51:24 PM »
Very interesting chemistry there.
I just want to caution people who are NOT chemists. (That would be most here I would safely bet)  Sodium Hydroxide, aka Lye will do TERRIBLE things to you.  Please do not put crystals of this into your coffee unless you KNOW what you are doing.

Did you try sodium metabisulfite?
Since you are already playing with caustics, TriSodiumPhosphate is a good oxygen scavenger, may help balance things a bit.

Aaron
As I have grown older, I have learned that pleasing everybody is impossible, but pissing everybody off is a piece of cake!

Offline ptrmorton

  • Standard User
  • ****
  • Posts: 956
Re: The Water Saga
« Reply #3 on: May 01, 2018, 03:12:02 PM »
Wow stevea, a lot of info to digest.  As a AZ guy, I can attest to "phoenix coffee".  Most coffee places just go with  RO water and call it a day.  I can also attest that my RO water for making coffee is improved when I mix it with some well water from the White Mountains.  However, pure "White Mountain" water isn't as good as the mix.  Gonna check the alkalinity. Next up - a batch of 70/30 water.    Thanks for posting stevea.
« Last Edit: May 01, 2018, 03:16:09 PM by ptrmorton »
AZ Peter

Proverbs 3:5-6

Offline Ascholten

  • Distributor
  • *****
  • Posts: 7547
  • Artisian 6 and Behmor
Re: The Water Saga
« Reply #4 on: May 01, 2018, 04:11:17 PM »
We have a nanopure machine at work.  It takes everything out, even deionizes the water down to parts per billion.  Super pure.  This is good to keep the scale out of your espresso boiler, coffee pot element, then as Steve said, adding flavor enhancers back in after you heated it up.

You know, that might be something, keep 'concentrates' in the kitchen of chemical mixes,  carbonate mixes whatnot, and just add a few drops or a squirt or whatever you need per cup of coffee.  Heat it pure, brew it great with carbonate.  :)

Aaron
As I have grown older, I have learned that pleasing everybody is impossible, but pissing everybody off is a piece of cake!

Offline stevea

  • Standard User
  • **
  • Posts: 214
Re: The Water Saga
« Reply #5 on: June 13, 2018, 08:42:29 PM »
[...] Sodium Hydroxide, aka Lye will do TERRIBLE things to you.  Please do not put crystals of this into your coffee unless you KNOW what you are doing.[..]

Did you try sodium metabisulfite?
Since you are already playing with caustics, TriSodiumPhosphate is a good oxygen scavenger, may help balance things a bit.

Aaron

Sodium hydroxide, slaked (pickling) lime, TSP - are all used in food processing in tiny measured amounts, but swallowing a teaspoon full of any would be a very bad idea.
My experience is that sodium metabisulfite leaves a pretty obnoxious sulfur note till all the sulfite is oxidized to sulfate, and the natural acidity of coffee would likely keep the sulfites around.  Also, some ppl are very sensitive to sulfites, even creating an anaphylactic reaction,  making it a bit dangerous too.  TSPp is actually a good idea, and I will give it a try, but 5 sodiums per 3 phosphates is a poor ratio and will hit the sodium limit before there is enough phosphate to be much of a buffer.

"Never put off until tomorrow what you can do the day after tomorrow."  Mark Twain

Offline stevea

  • Standard User
  • **
  • Posts: 214
Re: The Water Saga
« Reply #6 on: June 13, 2018, 09:13:54 PM »
Wow stevea, a lot of info to digest.  As a AZ guy, I can attest to "phoenix coffee".

Yeah, I used to spend a lot of time in 'the valley' a few decades ago, and a lot of hotels back then (even the high-end places) would make coffee from tap water.   Heck, as an outsider the shower water tasted salty, tho' I imagine you get used to it.  Guess they named it the Salt River for a reason.  Same for most of the SF area - from at least Berkeley to Los Gatos, tho' there the salinity was variable seasonally or based on drought.

You are absolutely right - RO water is inferior to a decent mix.  I can dilute 1 part of my (Ohio well) water 1:2 with RO and land in a better place than either.
"Never put off until tomorrow what you can do the day after tomorrow."  Mark Twain

Offline stevea

  • Standard User
  • **
  • Posts: 214
Re: The Water Saga
« Reply #7 on: June 14, 2018, 10:33:47 AM »
We have a nanopure machine at work.  It takes everything out, even deionizes the water down to parts per billion.  Super pure.  This is good to keep the scale out of your espresso boiler, coffee pot element, then as Steve said, adding flavor enhancers back in after you heated it up.

You know, that might be something, keep 'concentrates' in the kitchen of chemical mixes,  carbonate mixes whatnot, and just add a few drops or a squirt or whatever you need per cup of coffee.  Heat it pure, brew it great with carbonate.  :)

Aaron

Except the claim is that the bivalent cations - Calcium and esp Magnesium -  help extract flavors & aromas during brewing - and you won't get those cations w/o matching anions.  You *might* also need enough buffers during brewing to keep the pH high enough to avoid over-extraction - but that's a guess.   So I believe you'll want to brew with water w/ some decent amount of Ca&Mg, but very modest amounts of carbonate (the cause of 'scale').
"Never put off until tomorrow what you can do the day after tomorrow."  Mark Twain

Offline Ascholten

  • Distributor
  • *****
  • Posts: 7547
  • Artisian 6 and Behmor
Re: The Water Saga
« Reply #8 on: June 14, 2018, 01:27:24 PM »
Ive seen filter housings (which can also be used for ion beds or 'infusing beds' to put chemicals back in for flavor, that can stand 250 degree or so liquids.  you could also go stainless too.   Unless you are pumping through an espresso machine where this kind of mod might a bit more of a pain in the ass than normal, boil the water pure, run it thru the 'filter bed' to add your desired chems back in and then through the coffee or into the french press or whatever.

in other words,  heat pure, add flavorants then let it hit the coffee grounds.   pure keeps your heating elements clean, and then your flavor extractors can do their job after heating is done.   Again,a little squirt bottle or a mix of your PPM mixed to whatever you want,  pour pure water into french press, put 3 drops of your 'magic potion' in with it, then add coffee grounds.  or run it through filter / injector on way to pot, or ..something.  You seem the type who can figure out a delivery method pretty good.

Aaron
As I have grown older, I have learned that pleasing everybody is impossible, but pissing everybody off is a piece of cake!