another_jim wrote: Calcium and magnesium carbonate are found in all natural water. Sodium is added by ion exchange softeners that have been used for decades. Sulfate, on the other hand, is both a new idea, and has never been present in regular water, since it is classed as a contaminant. Moreover, it's not a regular kitchen ingredient either; its traditional household use is as a bath salt and constipation remedy. I was astonished to see it used in a coffee water recipe.

Adding magnesium sulfate to water is nothing new, it's in bottled water like Dasani(1). Also sulfates are natural occuring and are in peoples tap water. They only become a problem when the levels are elevated; just like sodium chloride and calcium bicarbonate (2). Lastly magnesium sulfate is not considered a contaminant. The FDA classifies it as Generally Recognized as Safe (GRAS) and regards it as a "flavor enhancer" & "nutrient supplement" (3). It's clear you have an opinion on TWW and the wider "Water for Coffee" style water recipes but that opinion is not grounded in fact.

(1) https://time.com/3029191/bottled-water- ... on-health/
(2) https://www.health.state.mn.us/communit ... ulfate.pdf
(3) https://www.accessdata.fda.gov/scripts/ ... r=184.1443

Um, quick version, https://water-research.net/index.php/sulfates, long version: https://www.epa.gov/sites/production/fi ... report.pdf The particular problems these reports cite are discoloring reactions with the bleach in cleaning products, and the growth of sulfur fixing bacterial films.

I have no problem with water recipes in general. I personally thought using Epsom salt was odd; but at 50 or so ppm, it is well below the 250 threshold the EPA permits. In terms of my personal peeves, it doesn't even make the top 1000. Now however there are a rash of problem reports with PIDed boilers; and the vendors say the problems are strongly correlated to the use of some particular custom water mixes. All of ones mentioned use Epsom salt as their non-scaling hardness source; while all the other recipe ingredients are found in naturally sourced waters.

So if you like your recipe and it works in your machine, fine. But if you are experiencing problems, and are using an Epsom salt recipe; try stopping.

A different kind of a question concerning the problem: why now? Is that because in the pandemic many more people started using water recipes (since we're sitting at home with more time to browse the forums, experiment etc.) Or is it a specific batch of components that hit the market a few months ago and made it to a large number of machines?

I only started using full rpavlis recipe recently. I'm finding the espresso made on it a little bit less pronounced and I was planning to start adding some Epsom salt (raising hardness by 20-40 max). Now I'm wondering, as many others probably are as well.

How about adding 10% to 20% tap water?

Sure, it's always an option. But it defeats the purpose of knowing exactly what's in your water and ruling out stuff that is harmful for the machine. If I mix distilled with 10% of my tap water, I actually get pretty much perfect parameters of what's needed: around 9mg/l Ca, around 2mg/l Mg, alkalinity of around 50, hardness around 35-40. But I also get some sulfates (around 5mg/l), some chloride (1.5mg/l) and who knows what else. So it does not seem like a fully controlled harmless environment, does it?

I still keep hoping someone can explain how the mineral content of water can cause a PID to fail?

Ira

Different and probably more accurate word, but it doesn't change the question.

Ira

ira wrote:I still keep hoping someone can explain how the mineral content of water can cause a PID to fail?

Ira

I have a theory

It used to be that almost all espresso machines (above the Gaggia Classic) had brass or copper boilers. On those boilers, there was no issue, as the thermocouples were mounted on the exterior of the boiler, or in a thermowell cast in the brass (like the v1 Silvia!).

These days, plenty of boilers are made from stainless steel pipe, and stainless steel doesn't have the thermal characteristics of copper or brass. Thus, the thermocouples have to go inside the boiler. The usual way (generically, not coffee machines) is with a thermowell:


-image from: https://www.instrumentationtoolbox.com/ ... 5.html?m=1

However, I am guessing that a separate thermowell + thermocouple combination was not used; a sheathed thermocouple was used. The essential difference for the matter at hand - corrosion resistance - is thickness. Metal sheaths around thermocouples can be very thin.

Now, Epsom salt is a sulfate. My guess is that if excessive sulfates were used or built up, then that will cause pitting of the alloy used for the thermocouple sheaths. The pitting starts all kinds of issues, especially if the sheathing is thin enough for the pits to eventually allow some leakage.

(Inconel 600 is probably the alloy to use, but it costs more. Inconel 600 still doesn't like sulfates, but it should be resistant enough to sulfates at coffee boiler temperatures.)

Just my guess.

Rufus T.F. wrote:Sure, it's always an option. But it defeats the purpose of knowing exactly what's in your water and ruling out stuff that is harmful for the machine.

So you avoid using an unknown amount of carbonates, calcium and magnesium, the normal minerals in drinking water, for a known amount of sulfate, a minor contaminant. Moreover, since sulfates are highly soluble, they won't scale in a steam boiler, no siree, you are safe! ... instead their concentration in a steam boiler will keep rising until you get a corrosive brew that eats at the seals and controls.

If you really believe that Epsom salts are a god send for tasty coffee -- purge your boiler weekly, i.e. run the water tap to flush out the water, and let the autofill refill it from the tank, one preferably filled with distilled water (and a dash of tap water to keep the conductance up).