This is a real wealth of info, if you haven't seen it - https://coffeeadastra.com/category/water-for-coffee/

That's a great link and a ton of information. I think the thing I appreciate most about what Pat advised is that I can use a simple filter on my tap water and then 1 or 2 simple amendments and get close to ideal brew water. I try to avoid waste where I can so I'm happy not to have to buy water and the associated bottles/containers.

I'll report back about what minerals I end up preferring.

So, I bought a HM Digital COM-100 TDS meter to do some verification. I set it up to run at the 0.7 setting since that seems best for drinking water.

I started with distilled water and was getting somewhere between 1.2-2.5ppm depending on which glass I poured the distilled water in.
Then I moved onto my tap water at 52ppm.
That same tap water filtered through the BWT pitcher was 40ppm. This is just before a filter change is due.
Just after a filter changes the BWT filtered tap water reads 44ppm.
The BWT filtered tap water (1 gallon) with .2g of potassium bicarb and .5g of Epsom salt added which came out to 162ppm.

Does this seem reasonable? Should I back off the minerals to get the TDS a bit lower?

So far my taste experiments have not been conclusive since it's a time lag to swap water in a machine with a 1L brew boiler. So I guess it's going to take a while of swapping water back and forth to gain some insights.

That's a nice TDS meter. But you can't just assume that 0.7 is the best calibration factor. Note in your case that your tap water has a conductivity of 84 microsiemens per centimeter and a TDS of 46.5 ppm. That's a conversion factor of 0.55. But your TDS number really doesn't matter that much. The important things are to get your alkalinity up to recommended levels, then make sure your undesirables like chloride and sulfate are nice and low, then consider whether you may have a scale prone hardness level. Knowing your TDS can help, especially with natural water. But focusing on precise TDS is letting the tail wag the dog.

In your case i'll stick with my earlier opinion - keep that 0.2 gram per gallon bicarbonate spike to give you machine healthy buffer. Then taste experiment with less or no additional Epsom salt. Use less if the taste is fine.
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Thanks Pat.

I'm not sure I follow about how to determine whether to use the 0.5 or 0.7 factor correction but I do understand that none of these inexpensive meters are going to be accurate enough to give a real world number outside of my own relative testing.

I am going to continue to use the Potassium Bicarb and drop the Magnesium Sulfate down some after I get a better handle on how this tastes. The lag introduced by the amount of water that needs to be exchanged in the boiler makes back to back comparisons impossible.

Since you've helped me better understand brew water I've been paying closer attention and asking more questions to the roasters I buy from. One of the best ones is Phil & Sebastian. They put brew water recommendations on every coffee page and it's a very interesting makeup.



I've had quite a lot of success with their coffees and now I think I understand why. The tap water I've been using isn't far off their recommendations. I'm guessing that you might say that this water may be borderline unsafe for boilers?

Once again thanks for taking the time to explain these things. I feel like I'm starting to get a rudimentary handle on this important component of our silly hobby making tiny drinks.

PIXIllate wrote:Since you've helped me better understand brew water I've been paying closer attention and asking more questions to the roasters I buy from. One of the best ones is Phil & Sebastian. They put brew water recommendations on every coffee page and it's a very interesting makeup.

It certainly is!

18 mg/L HCO3 is an alkalinity of only 15 mg/L. That's getting pretty low, but I suppose if you are confident that the water is free of chloride and sulfate you could live with that. The recommendation from SCA is that you need at least 40 mg/L alkalinity, but that probably allows for a range of tap water with some 'undesirable' mineral content. The R. Pavlis water recipe recommendations allowed for a 25 mg/L alkalinity in pure water with nothing but bicarbonate. Dr. Pavlis said that he preferred the low alkalinity recipe version when brewing dark roasts.


5 ppm Ca and 2 ppm Mg is oddly precise. It's probably what happens to come out of their RO unit up in Calgary. In hardness units it would be 12.5 ppm calcium hardness and 8.2 ppm magnesium hardness (in CaCO3 equivalents) for a GH of 21 ppm.

It's always interesting to see recommendations that fall outside of the conventional wisdom. This would be well down in the lower left corner of the old SCAA "adequate brew" zone, at hardness = 21 and alkalinity = 15 on my hardness:alkalinity chart.

PIXIllate wrote:The tap water I've been using isn't far off their recommendations. I'm guessing that you might say that this water may be borderline unsafe for boilers?

That Pockwock tap water, with alkalinity of 21.5, hardness of 11.3 (ppm CaCO3 equivalent) , and chloride ion of 8.5 ppm, is in the ballpark of their recommendation, and I think you might* safely use it. For charcoal filtration of that water I think I'd avoid any filter that contains a WAC resin, which includes most pitcher filters out there. (WAC resins tend to drop the alkalinity and acidify the water, and you don't want that if you have low alkalinity and some chloride in the water.) The new Brita Longlast has no WAC resin and would be OK. Most refrigerator filters have no WAC resins.

* Although I still think that a small bump in alkalinity by adding sodium or potassium bicarbonate would make it safer and in my opinion would not detract at all from the taste of the espresso. You might possibly detect a difference when tasting the coffee by cupping, but espresso tolerates much more alkalinity.

Pat,

I've been using just my filtered tap water without any amendments for the past 5-6 days as I'm currently pulling the P&S coffee. I still have some more experimenting to do but so far I'm not sure if the Epsom salts are adding anything positive, as you suggested they may not.

I'm going to try just the 0.2g of potassium bicarb in my next gallon of brew water while still pulling the other bags of P&S I have.

From what I have learned from you and others the higher alkalinity created with the bicarb is MUCH more significant with pourover or cuppings as water is a much larger component of those drinks while espresso is less effected due to the much smaller quantities. Additionally the bicarb makes the water much safer for steam boilers and is not necessary for kettle safety as they are easy to descale.

Do I have this line of thinking correct?

I am considering switching from the BWT water filter to the Brita that you mention. Is the further acidification produced by the WAC filter still an issue if I amend with bicarb? I've heard that the Brita filters are PAINFULLY slow. Do you have any personal experience with them? I have to say the BWT does produce very nice tasting drinking water.

PIXIllate wrote:From what I have learned from you and others the higher alkalinity created with the bicarb is MUCH more significant with pourover or cuppings as water is a much larger component of those drinks while espresso is less effected due to the much smaller quantities. Additionally the bicarb makes the water much safer for steam boilers and is not necessary for kettle safety as they are easy to descale.

Do I have this line of thinking correct?

The first sentence, about alkalinity having more effect with pourover and cuppings, yes. You've probably already seen it, but for others who want to see the logic and numbers, here's an article by Marco Wellinger: https://scanews.coffee/25-magazine/issu ... e-issue-9/

The second sentence I would word differently. Adding bicarb to a given hardness water does not reduce the need to descale; it actually may increase it. Having a good level of alkalinity does, however, tend to reduce the risk of corrosion, especially if the water is below around 40 mg/L alkalinity. It's especially important in espresso machines because pinhole corrosion can be very expensive, sometimes catastrophic in a vintage machine.

The best reference for understanding how alkalinity and hardness together tend to cause scale deposits is the Insanely Long water FAQ that Jim Schulman (another_jim here on HB) posted on the alt.coffee newsgroup many years ago.

PIXIllate wrote:I am considering switching from the BWT water filter to the Brita that you mention. Is the further acidification produced by the WAC filter still an issue if I amend with bicarb? I've heard that the Brita filters are PAINFULLY slow. Do you have any personal experience with them?

If using the BWT and bumping the alkalinity up to par with bicarb I see no reason to worry.

I'm currently using the Brita Longlast for drinking water in my fridge. It does filter more slowly than the standard Brita filters. I like it because it's well over-capacity (about 120 gallon per filter change) for my use rate and I don't have to track how much it has filtered - just replace it every 6 months by the calendar. I don't have a water tap and filter on my fridge -- If I did I would just use that instead of the Brita.

Pat,

Thank you for your clarifications. I can see where I misspoke and I do understand the two extremes of machine safe water now. Also, that article is just excellent. Very well written and clear in it's demonstration of the variables at play and the mechanisms through which they work. Worth reading or even a sticky. One thing that stood out for me was the last paragraph:

"Carbonate hardness is another way of saying the common minimum of total hardness and alkalinity. An easy metaphor for this involves dancing partners, where the number of pairs you can form is limited by whatever count is lower the number of people who want to "take the lead" and those who want to follow through. So, if you want to make sure there is at least 40 mg of protective layer per liter of water able to form in your boiler, neither total hardness nor alkalinity may be below 40 mg of CaCO3 per liter (40 ppm CaCO3)."

So, would this make a case for someone with water like mine adding a small amount of hardening in the form of Epsom salts just to get it to equal the amount of alkalinity I'm targeting?

PIXIllate wrote:So, would this make a case for someone with water like mine adding a small amount of hardening in the form of Epsom salts just to get it to equal the amount of alkalinity I'm targeting?

I think you are under the impression that since your water has an alkalinity higher than the hardness, there is no downside to adding more non-carbonate hardness because until it is higher the the alkalinity, your carbonate hardness is still the same. That's true, but carbonate hardness (as properly defined by Marco Wellinger) is not all by itself the predictor of scale risk. It's a little more complex than that - has to do with the product of the hardness ion concentration and the carbonate ion concentration, so if hardness goes up and carbonate stays the same you still get increased scale risk. Also with respect to scale, calcium is more scale prone than magnesium. But in your case you could certainly add a small amount of Epsom to your recipe without increasing the scale risk if you thought it made the coffee taste better.

P.S.
That definition of 'carbonate hardness' by Marco Wellinger is well explained, and is the proper definition in my opinion. It's also the way Hach and most water chemistry literature define it. But you often see that term defined differently, so that "carbonate hardness" is a measure of the amount of carbonate and bicarbonate in the water - essentially equal to the alkalinity irrespective of hardness ions. Wikipedia, unfortunately, currently favors that definition.

All of the drop titration tests that purport to measure carbonate hardness are actually simple alkalinity titrations. With typical natural waters it's moot, because the total hardness of natural water is almost always higher than the alkalinity, so you can measure alkalinity and call it KH, or carbonate hardness, or temporary hardness and be correct. For softened water or recipe water, where you may have little or no hardness ions and plenty of carbonate ions, using the term carbonate hardness for an alkalinity measurement is confusing, and using the term temporary hardness is just wrong.