Rpavlis water in Breville Dual Boiler

#1: Post by **oksako** » April 27th, 2022, 6:34 am

Hi!

I came across this topic Lelit Bianca, particles forming in boiler (rpavlis water) and out of curiosity I contacted Lelit and Breville to ask about what they think about such recipes. Lelit did yet now answer and with Breville I chatted using their love chat with the following result:

Me

I am about to buy a Sage (Europe) dual boiler and I want to use the best water I can to protect the machine (non-scaling water). I have seen many users using rpavlis water recipe: "The recipe simply calls for 100 milligrams (0.1 grams) of potassium bicarbonate per liter of pure water."
This would yield a water without hardness which is supposed to protect against corrosion and scaling.
Because I am not a chemical expert I wanted to ask you if such a formula is good or harmful to the machine.

They:

Well i would really advise to use our water filters wit hthe different scale for hardness
It is included in every new coffee machine and designed by following exactly the different stages .
Yana

Me:

Sure if I would use normal tap water I would use the filter but I want to understand if I can use pure water with the formula above so that I NEVER have to be afraid of scale because the water has no scaling components.

They:

Well, I will not recommend to use other solutions as the machine is designed this way. Of course, you can try but if a damage is detected, this might lead to voiding your warranty.

That's it.
I assume the person I was talking to was just a 1st level support, however, that's was strange.

I know what you think about rpavlis water. However did you ever spoke with an expert (e.g. 3rd level support) from the company regarding rpavlis water? As I said, in the beginning, the lelit bianca topic confused me a little considering #21 on page 3.

Best regards
Okan

#2: Post by **Smo** » April 27th, 2022, 7:02 am

I know you have a water specialist.
Can distilled water + NaHCO3 40 mg/l be used?

#3: Post by **tennisman03110** » April 27th, 2022, 8:06 am

I've used Rpavlis in my BDB for two years. The insides look like new. Tank is always super clean, it always has some water in it. Never really clean it.

No disrespect to the Breville rep, but they are not experts in espresso machines, or really any appliance. They've got standard responses for most things, and field a wide variety of questions. Just try asking them about the Slayer mod

April 28th, 2022, 1:22 am

Compared to the Breville support I got a much more qualified answer from Lelit, which really let me again think about my decision (bdb vs Elizabeth.. Feels like a never ending story haha)

thank you for your message.

We are not chemical experts but we can indicate the water profile that we consider suitable for our coffee machines.

Ideal water for coffee machine has a pH 6.5-8, alkalinity of 40-70 ppm CaCO3 and a total hardness of 60-120 ppm CaCO3, water free of chlorine and chlorides below 50 ppm.

Considering #3 in No Water Alkalinity. Good or Bad? I would get the recommended alkalinity using rpavlis recipe. But why should I add hardness? Is this only for taste or does it has to do with machine protections as well? Also wouldn't I increase the potential of scale when I add hardness to my water (let's say using Epsom salt, right?).

Edit: Considering Using hot water tap to manage steam boiler water concentration (thanks pat for all this awesome information) would I also have to care much more about the water in the steam boiler because the hardness would become more concentrated there?

Thank you for your time!!

Best Regards

#5: Post by **Smo** » April 28th, 2022, 4:42 am

https://dailycoffeenews.com/2018/08/29/ ... sory-data/

Here is an interesting article, you will be very surprised to read about distilled water.

#6: Post by **homeburrero** » April 28th, 2022, 6:29 pm

oksako wrote:Considering #3 in No Water Alkalinity. Good or Bad? I would get the recommended alkalinity using rpavlis recipe. But why should I add hardness? Is this only for taste or does it has to do with machine protections as well? Also wouldn't I increase the potential of scale when I add hardness to my water (let's say using Epsom salt, right?).

There is a long-standing concept of 'protective scale' that I think drives some of the manufacturers to recommend that your water have hardness minerals, the idea being that some limescale coating is desirable to protect the metal surfaces from corrosion. I think most water corrosion experts got away from this idea years ago. Dr. Pavlis pointed out that limescale deposits are not at all uniform, and are also porous and don't provide protection. More importantly, if you do use scale prone water you will need to periodically descale, and descaling can remove thin oxide layers that actually do provide corrosion protection. The bicarbonate level in the R Pavlis recipe is near ideal for maintaining a healthy oxide layer on copper and brass.

Then there's a long held conventional wisdom that you need hardness minerals for optimal taste. That idea was bolstered by computational chemistry experiments in a 2014 paper by Hendon and Colonna-Dashwood. Their summary said that their experiment provided a compelling argument that Mg++ and Ca++ rich water would provide a favorable extraction yield, with magnesium having the advantage of not increasing limescale risk. This paper, plus the Hendon and Colonna-Dashwood Water for Coffee book, and the Barista Hustle water discussions have generated a lot of interest making coffee water with magnesium hardness. Measurements of extraction yields have failed to show higher extractions with magnesium or calcium rich waters, and I think the idea that you need any hardness minerals to make tasty coffee is not well supported. For those interested in the latest ideas on that, check out today's Instagram post by Samo Smrke here: . And especially the excellent thesis paper he references -- Tove Bratthäll's Influence of divalent cations on extraction of organic acids in coffee -- PDF available here: https://www.diva-portal.org/smash/get/d ... TEXT01.pdf

Dr. Pavlis sometimes made the compelling argument that adding hardness minerals to the brew water makes little sense when you consider the fact that the water flowing through the coffee bed is rich in these minerals irrespective of the small amount that came in with the brew water. The water coming out the bottom of the PF basket will have over 3000 mg/L of magnesium in CaCO3 equivalents. So whether you have soft water with 10 mg/L hardness or BH water loaded with 100 mg/L, the difference in the solvent flowing through the coffee bed would be insignificant.

oksako wrote:Considering Using hot water tap to manage steam boiler water concentration (thanks pat for all this awesome information) would I also have to care much more about the water in the steam boiler because the hardness would become more concentrated there?

For those with HX or DB systems we don't need to worry about the possible effect of concentrated minerals on extractions and taste, but do have to be especially vigilant about scale because the steam boiler is hotter as well as subject to concentration through steam wand use. So using rpavlis here gives you a lot more breathing room -- even after becoming highly concentrated in the steam boiler there is no silica, calcium sulfate, calcium carbonate, magnesium hydroxide, - - nothing in there that would create scale.

May 11th, 2022, 2:21 am

homeburrero wrote:There is a long-standing concept of 'protective scale' that I think drives some of the manufacturers to recommend that your water have hardness minerals, the idea being that some limescale coating is desirable to protect the metal surfaces from corrosion. I think most water corrosion experts got away from this idea years ago. Dr. Pavlis pointed out that limescale deposits are not at all uniform, and are also porous and don't provide protection. More importantly, if you do use scale prone water you will need to periodically descale, and descaling can remove thin oxide layers that actually do provide corrosion protection. The bicarbonate level in the R Pavlis recipe is near ideal for maintaining a healthy oxide layer on copper and brass.

Going through the forum I also saw many posts from rpavlis pointing out the oxide layer which will build up over time. Especially considering a brass boiler (e.g. Lelit Elizabeth) this would be, for my understanding, a good thing for protection and drastically reducing the risk of lead leakage as long as one wouldn't descale (which wouldn't be necessary with rpavlis).

homeburrero wrote:Then there's a long held conventional wisdom that you need hardness minerals for optimal taste...

I would like to leave this as a conventional wisdom for now instead of bothering with it. To protect the machine I would prefer rpavlis water from scale buildup perspective.

homeburrero wrote:Dr. Pavlis sometimes made the compelling argument that adding hardness minerals to the brew water makes little sense when you consider the fact that the water flowing through the coffee bed is rich in these minerals irrespective of the small amount that came in with the brew water...

Meanwhile I also researched the water which is sold as 'distilled' here in Germany by contacting the company. We had a discussion related to this in Remineralise Water #6. The company told me that it the 'distilled' water is either RO water or (more often) DI water. Free of chemical or bacterial contamination. I also asked them about the risks of drinking that water, because of the label 'Not recommended as drinking water'. Basically they told me that it isn't in issue unless one inject the water directly into ones blood system and unless one invariably drinks the distilled water in enormous amounts combined with a very unbalanced diet. So I think everyone can decide for themselves whether this water can be used to mix rpavlis water or. At least I know that I can use it without risking anything. One more thing, I also asked a local pharmacist explaining what I want to do. He also basically said that the water should be OK.

To start my journey I just have a few more questions to be really sure what I am doing and hope, that one can support me:

Is it better to use baking soda or potassium bicarbonate? The latter was not available in the pharmacy and the pharmacist brought me baking soda as an alternative. However, I can order potassium bicarbonate via the pharmacy, which I would do if it is better?
I found another bottled water which has low minerals. But for my understanding, rpavlis water will always be better in terms of no-scale buildup, right? (the bottled water would have 15.8mg/l calcium, 4.7mg/l magnesium, 17.4 sulfate (considering some of rpavlis posts, this could lead to sulfat scale, right?), 24.8mg/l chloride, 45.8mg/l hydrogen carbonate).
I have found that the machines I'm considering (Lelit Elizabeth and Lelit Mara X) will heat up the water during their warmup period to approx. 140 C/284 Fahrenheit. I know that hotter water will scale more (sciolism). However, I assume that with rpavlis water this will be no issue at all, correct?
Just to be sure, rpavlis water is not acidic so that it wouldn't damage brass boilers or coatings inside them, right?
I found weird snow flake-like things on the tubes on the Lelit Elizabeth I ordered (see image below), also some water came out after using the steam knob. Either the water is from someone else who tried the machine and send it back or this is water from tests Lelit made after production. But what are those snow flake? (see image below) Production residuals? Will using very hard water once is bad (assuming someone else did this)?

#8: Post by **homeburrero** » May 11th, 2022, 12:39 pm

oksako wrote:Is it better to use baking soda or potassium bicarbonate? The latter was not available in the pharmacy and the pharmacist brought me baking soda as an alternative. However, I can order potassium bicarbonate via the pharmacy, which I would do if it is better?

Either is fine. Dr Pavlis preferred potassium, and offered the rationale that using potassium should not affect taste because coffee is already loaded with lots of potassium. If you use baking soda (sodium bicarbonate) at 84 mg/L you will have 23 mg/L of sodium in your water, and it may be worth noting that the old SCAA water recommendation was that around 10 mg/L sodium was ideal and that over 30 mg/L was perhaps too much.

oksako wrote:I have found that the machines I'm considering (Lelit Elizabeth and Lelit Mara X) will heat up the water during their warmup period to approx. 140 C/284 Fahrenheit. I know that hotter water will scale more (sciolism). However, I assume that with rpavlis water this will be no issue at all, correct?

Correct. Limescale is calcium carbonate, and other things that might form 'scale' deposits are magnesium carbonate, magnesium hydroxide, calcium sulfate, and silica. Rpavlis water has zero calcium, magnesium, sulfate, and silica, so none of these will form even if the water is heated and concentrated.

oksako wrote:Just to be sure, rpavlis water is not acidic so that it wouldn't damage brass boilers or coatings inside them, right?

Right. At room temp and in equilibrium with air it has a pH of around 8.2 and an alkalinity (acid buffering capacity) of 50 mg/L as CaCO3. The half-strength recipe would have a pH of around 7.9 and an alkalinity of 25 mg/L as CaCO3.

oksako wrote:I found weird snow flake-like things on the tubes on the Lelit Elizabeth I ordered (see image below), also some water came out after using the steam knob. Either the water is from someone else who tried the machine and send it back or this is water from tests Lelit made after production. But what are those snow flake? (see image below) Production residuals? Will using very hard water once is bad (assuming someone else did this)?

I have no idea what those snow flake-like things are, but I wouldn't let that bother me. It's normal for new machines to arrive with evidence of use. Ideally they are given a QA test by the vendors, and the water they use will have some mineral, and even if this water is soft you can have dry residue left on wet surfaces that have dried out. That residue will dissolve with use.

May 13th, 2022, 3:10 am

Thank you very much for your reply. Reading through other threads always leads me to the question, why so often brita filters and in tank filters are recommended, while rpavlis water seems to be the allrounder/no brainer solution?

#10: Post by **tennisman03110** » May 13th, 2022, 8:44 am

A Brita won't soften water. It's an excess of minerals that cause scale. Starting from zero and adding your own salts, etc is foolproof.

I'm not sure what other threads you're referring to, but on this site most won't advise the simple tank or pitcher filters.