Raise pH of RO water for kombucha

[kombujo]

How do you raise the pH of RO water?
It takes around 300mg/L of sodium bicarbonate to raise my water pH to around 7.
I have played around with sodium carbonate and this required much less.
I have also been using a mix of calcium carbonate and sodium bicarbonate.
Keen to hear how others raise their pH?
Thanks

 

[VikeMan]

Well, I don't make kombucha, but I can tell you that slaked lime (aka pickling lime, calcium hydroxide) is slightly more effective (by weight) than sodium bicarbonate at raising pH of solutions.

 

[hottpeper13]

My RO water is 6.8 pH. Why do you need 7 for booch? My finished booch has a 2.85 pH

 

[kombujo]

My RO water is 6.8 pH. Why do you need 7 for booch? My finished booch has a 2.85 pH

My RO water is around 5.5pH, hence why I want to raise it

 

[Yooper]

My RO water is around 5.5pH, hence why I want to raise it

You don't want to raise it! The idea is to have enough starter tea to keep the pH low, so that you have an environment inhospitable to unwanted microbes (like mold).
RO water will drop in pH when it is exposed to the environment since it has very little buffering, but that isn't at all something to worry about.

 

[kombujo]

You don't want to raise it! The idea is to have enough starter tea to keep the pH low, so that you have an environment inhospitable to unwanted microbes (like mold).
RO water will drop in pH when it is exposed to the environment since it has very little buffering, but that isn't at all something to worry about.

My booch drops to around 2.5 when ready and with a higher starting ph it buffers this giving more like 2.8 to 3. So I'm still wishing to raise the Ph of my water.

 

[VikeMan]

My RO water is around 5.5pH, hence why I want to raise it

With RO (or distilled) water, it's helpful to pretend that it doesn't even have a pH. The affect that it has on the pH of anything it's mixed with is very small.

 

[kombujo]

With RO (or distilled) water, it's helpful to pretend that it doesn't even have a pH. The affect that it has on the pH of anything it's mixed with is very small.

That's interesting, I've not heard this before. I do however wish to remineralise the water anyhow, so 2 birds 1 stone. Still keen to hear how people remineralise/raise PH of water.

 

[Yooper]

With RO (or distilled) water, it's helpful to pretend that it doesn't even have a pH. The affect that it has on the pH of anything it's mixed with is very small.

Right. That's what I'm trying to say- the RO water has a higher pH but it has NO buffering so it's absorbed some air from the atmospshere. It's fine, and the pH here is immaterial.

 

[Yooper]

That's interesting, I've not heard this before. I do however wish to remineralise the water anyhow, so 2 birds 1 stone. Still keen to hear how people remineralise/raise PH of water.

Most people don't raise the pH of the water except it very rare cases. They may raise the alkalinity/bicarbonate level, again, in very unusual cases. Some add some minerals for brewing beer, like calcium chloride, but for the most part RO water is fine for kombucha because you add sugar (nutrients for the SCOBY).

 

[kombujo]

Most people don't raise the pH of the water except it very rare cases. They may raise the alkalinity/bicarbonate level, again, in very unusual cases. Some add some minerals for brewing beer, like calcium chloride, but for the most part RO water is fine for kombucha because you add sugar (nutrients for the SCOBY).

I would like to get the best flavour from the tea. RO water gives tea a flat finish. I want TDS around 150.

 

[Yooper]

I would like to get the best flavour from the tea. RO water gives tea a flat finish. I want TDS around 150.

Well, it's your kombucha- but the tea may have a flat finish, but the kombucha gets it's flavor from the SCOBY and fermentation, and not from the tea. I wouldn't mess it with it at all, and perhaps give a tiny bit of calcium chloride if you feel that you have to, but no way would I add any alkalinity. You want a healthy SCOBY and that doesn't play well with alkalinity.

I've been doing this a LONG time, and never had a failed batch or any issues. You asked a good question, and we've given you answers but the choice is yours.

 

[kombujo]

Thank you for your help and suggestions.
I'm a bit of a tea nerd. I find there to be quite a difference in a straight cup of tea, depending on the mineral content of the water used, I assumed that this would also translate over in to kombucha.

 

[hottpeper13]

I find the same flatness with coffee when I use RO water. Can I ask why you are using RO instead of tap? I have very high cal-mag in my well water and find that my best fermentation and flavor come when I use 2 qts of tap in a 2 gal batch. If you are buying RO just switch to a spring water that has the 150 TDS you want. If making RO , mix it up a bit. By chance do you know the pH of the tea before you add the starter and scoby?

 

[kombujo]

I am in India and despite having access to well water and government water I prefer to use my RO filter. I do not boil the water so cannot remove potential contaminants. PH of sweet tea is around 5 to 5.5 (if no water treatment)

 

[Buckeye_Hydro]

How do you raise the pH of RO water?
Keen to hear how others raise their pH?

To repeat the content of other posts but use some different words...
Nearly all the buffers have been removed from RO water. This means it has almost no capacity to resist a change in pH. It will assume the pH of whatever you add it to, or whatever you a add to the RO water. THAT's why people are advising you not to be concerned about the pH of your RO water.

It is below 7 now because it absorbed CO2 (which converts to carbonic acid) from the atmosphere.

Now... if you want to add minerals to adjust flavor rather than pH, that is a different discussion.

Russ

 

[kombujo]

Thanks Russ.
Can you recommend minerals to adjust flavour?

 

[VikeMan]

Can you recommend minerals to adjust flavour?

Calcium Chloride
Calcium Sulfate

 

[Buckeye_Hydro]

Will calcite (calcium carbonate) work?