Hi all!

This is my first post on HB. I've been reading a lot here recently and have learned a lot already - thank you all for that! It has already cost my a lot of money though, since this forum 'forced' me to pull the trigger on buying a Solis Triple Heat (which is essentially the same a a Breville Dual Boiler if I understood correctly). I've previously owned a Breville Barista Express and before that, a Delonghi Dedica 685 (in combination with a Hario Skerton).

I'd like to take care of my new machine from the very start. Hence, I've tried to build a water recipe. I'm not a chemist by any means, so it's all quite hocus pocus tbh, but from what I've learned, there are four prerequisites for water in an espresso machine.

Water should:
- be non-corrosive
- be scale free
- enhance espresso flavour
- not harmful to the body i.e. safe for consumption

Therefore, I've tried to build a recipe that looks as follows:

Concentrate:
- 100ml distilled water
- 1gr Epsom salt (Magnesiumsulfat-Heptahydrat (MgSO4*7H2O))
- 0.75gr Potassium bicarbonate (KHCO3)
- 0.75gr Natron (Sodium bicarbonate (NaHCO3))

Brew water:
- 995ml distilled water
- 5ml concentrate

I was hoping that you guys could comment on my recipe and perhaps help my verify if this recipe meets the four prerequisites - not just for my new espresso machine, but also for my V60 brews. I'm fairly new to this, so please go easy on me!

Bas

It looks fine in terms of your final concentrations - gives you 41 mg/L bicarbonate alkalinity and 20 mg/L magnesium hardness in CaCO3 equivalents.

Most people mix their hardness concentrate and their carbonate concentrate in separate bottles. If you put them together in one bottle you risk getting a carbonate precipitate. In your case, where you have no calcium and a small amount of magnesium you should be OK. Still might be best to use two concentrate bottles so you can keep the alkalinity at that level but experiment with using more or less of the magnesium concentrate in your final mix.

homeburrero wrote:[...] Still might be best to use two concentrate bottles so you can keep the alkalinity at that level but experiment with using more or less of the magnesium concentrate in your final mix.

That is exactly what I am doing. My recipe actually looks as follows:

Concentrate 1:
- 100ml distilled water
- 1gr Epsom salt (Magnesiumsulfat-Heptahydrat (MgSO4*7H2O))

Concentrate 2:
- 100ml distilled water
- 0.75gr Potassium bicarbonate (KHCO3)
- 0.75gr Natron (Sodium bicarbonate (NaHCO3))

Brew water:
- 990ml distilled water
- 5ml concentrate 1
- 5ml concentrate 2

For V60 brews, I feel safe to double or triple the amount of concentrate 1, but I'm not sure to what degree it would be machine-safe. Won't higher concentrations of epsom salt deposit some sort of scale?

Furthermore, reading the legacy of Dr. rpavlis, I noticed he only uses potassium bicarbonate - but why? What are the pros of this? And what are the cons for sodium bicarbonate?

In order to keep my machine healthy for a loooong time, what cleaning procedures should I follow, besides the regular back-flushes?

homeburrero wrote:[...] In your case, where you have no calcium and a small amount of magnesium you should be OK. [...]

Can I conclude from Homeburrero's comment that descaling is not necessary?

Bas

Tak0 wrote:Furthermore, reading the legacy of Dr. rpavlis, I noticed he only uses potassium bicarbonate - but why? What are the pros of this? And what are the cons for sodium bicarbonate?

Dr Pavlis said you could use either, but preferred the taste using potassium, and made a convincing argument that since coffee is loaded with potassium you could use lots of that without doing anything to affect the taste.

In old guidance from the SCAA water quality handbook they recommended about 10 mg/L sodium ion as optimal (and never really explained why). Your recipe comes out to about 10 mg/L sodium.

Tak0 wrote:Can I conclude from Homeburrero's comment that descaling is not necessary?

I'd say never descale unless you see some scale buildup, and with your water you will probably never see scale buildup. You do have magnesium ion and bicarbonate ion in the water, and that opens you up to the theoretical possibility of magnesium carbonate and magnesium hydroxide precipitating as scale when the water is heated. But magnesium is far less likely than calcium to scale, and the usual prediction formulas for scale, based on hardness, alkalinity, temp, and pH, are based on calcium rather than magnesium hardness. We've seen reports of people using barista hustle recipes with magnesium hardness as high as 100 mg/L with bicarbonate alkalinity of 50 mg/L (CaCO3 equivalent) and not reporting any scale.

If you do a lot of steaming and don't offset that with occasional draining of your steam boiler, or with frequent purging of water from the hot water tap, then you can end up concentrating the minerals in the steam boiler, which might cause some scale.