A Note on Potassium Carbonate

[Boatboy24]

Just a note: I've now had the 'opportunity' to dose a handful of wines over the last few years that have somehow ended up with low pH after fermentation (numbers were decent, or very good prior). In all cases, pH increased and the wines improved significantly. I've been using the MoreWine example of 1g/L to increase pH by 0.1. In all cases, I've overshot. So I highly recommend treating this like you would any other acid adjustment. Start with half the dose you think you need. If you need to repeat, so be it. But it is better to come up short of your goal and repeat the process than to overshoot.

 

[ibglowin]

The only time I have used any type of acid reducing agent I figured out what I needed to get to a pH ~3.65 then added only 50% of what was supposedly needed.

Added that in and stirred well. Checked the pH after letting settle for a few hours. My pH was 3.65.........

 

[Johnd]

I'll certainly third that opinion, my method and experience is the same, calculate the amount needed, put in half, and the wine is generally in the desired range.

 

[Tnuscan]

Ditto.

Bench trials are suggested, and even these, with pH adjustments, can try the patience of a saint.

 

[AKsarben]

We bump the wine acid up on occasions, but use tartaric acid and figure 15% will fall out as cream of tartar. Other acids, no. Our apple ciders are always low acid and high pH, so we generally bump up the acid from .300 eg to .600 by adding 0.3% Malic acid, and that does not loose any of the acid. pH will come down accordingly. Above is just an example of acid adjustment. We rarely adjust based just on pH.

 

[Ajmassa]

Just a note: I've now had the 'opportunity' to dose a handful of wines over the last few years that have somehow ended up with low pH after fermentation (numbers were decent, or very good prior). In all cases, pH increased and the wines improved significantly. I've been using the MoreWine example of 1g/L to increase pH by 0.1. In all cases, I've overshot. So I highly recommend treating this like you would any other acid adjustment. Start with half the dose you think you need. If you need to repeat, so be it. But it is better to come up short of your goal and repeat the process than to overshoot.

What I saw on morewine went by TA. 3.8 g/gal reduces by TA by .1%. So if 3.8g/gal is the same 1g/L to raise ph by .1 then potassium carbonate effects TA and Ph proportionately ? (3.8 L in a gallon)
But it also mentions the need to cold stabilize. Am I correct to assume adding potassium carbonate prior to AF is a simple addition that raises ph in a couple hours. But added after AF requires cold stabilization. And do the numbers for TA and ph remain proportionate moving down and up by .1 respectively when done after AF?
I ask because Adjusted TA before AF with tartaric as it was extremely low at .325% Raised to .425%. But inadvertently also lowered ph from 3.4 to 3.2. Haven't checked TA since then. I'm waiting until after MLF. Hoping these numbers shift. So far ph hasn't. What I really need is a way to check levels of specific acids I think. All I know for sure is that there's no more malic. And plenty of lactic. Low ph as well as TA just doesn't make sense to me.

 

[AKsarben]

We never add Potassium carbonate before fermentation, and only on some rare occasions after. We have used calcium carbonate to completely neutralize only a small portion of a high acid juice, which is done in separate tank. Rack off the juice that has basically no acid and pump back into the main batch. It is in effect taking all the acids out and a lot like diluting with water, but it's actually juice. It will raise pH, but if the wine was very low to begin with (high acid) such as 3.00 the increase of pH is alright. Later the finished wine can have Tartaric acid added back in if the TA is not up to where we want it. Usually done around cold stabilization.

 

[Ajmassa]

We never add Potassium carbonate before fermentation, and only on some rare occasions after. We have used calcium carbonate to completely neutralize only a small portion of a high acid juice, which is done in separate tank. Rack off the juice that has basically no acid and pump back into the main batch. It is in effect taking all the acids out and a lot like diluting with water, but it's actually juice. It will raise pH, but if the wine was very low to begin with (high acid) such as 3.00 the increase of pH is alright. Later the finished wine can have Tartaric acid added back in if the TA is not up to where we want it. Usually done around cold stabilization.

You gonna be in Jersey any time soon? I'll leave a key under the mat for ya!

 

[Greg_Salyer_13]

According to this: http://www.bcawa.ca/winemaking/acidph.htm

"potassium carbonate reacts immediately and does not leave a deposit"

So is cold stabilization required after and if so, how long for 6 gal at 32 F?

What I saw on morewine went by TA. 3.8 g/gal reduces by TA by .1%. So if 3.8g/gal is the same 1g/L to raise ph by .1 then potassium carbonate effects TA and Ph proportionately ? (3.8 L in a gallon)
But it also mentions the need to cold stabilize. Am I correct to assume adding potassium carbonate prior to AF is a simple addition that raises ph in a couple hours. But added after AF requires cold stabilization. And do the numbers for TA and ph remain proportionate moving down and up by .1 respectively when done after AF?
I ask because Adjusted TA before AF with tartaric as it was extremely low at .325% Raised to .425%. But inadvertently also lowered ph from 3.4 to 3.2. Haven't checked TA since then. I'm waiting until after MLF. Hoping these numbers shift. So far ph hasn't. What I really need is a way to check levels of specific acids I think. All I know for sure is that there's no more malic. And plenty of lactic. Low ph as well as TA just doesn't make sense to me.

 

[GreginND]

I always recommend cold stabilization anytime potassium is added as your balance of potassium to acid will be changed.

 

[JimInNJ]

Cold stabilization will then further lower acidity but also lower pH, depending on the starting pH. Is that correct? Is that planned for when adding the potassium?

 

[Ajmassa]

Haven’t been able to read that article yet.
But yes. 3.65ph is the magic number they say. Cold stabilizing under that ph will lower TA AND lower ph. Done to a wine above 3.65ph will raise ph while lowering TA.
I just recently did CS (without using any acid removing chems) to 2 wines both under 3.65ph and the levels moved as they said.

 

[JimInNJ]

So, if I wanted to increase the pH of a wine from say 3.30 to 3.40, I could do so by adding potassium carbonate. But then I would cold stabilize and the pH would go back down, possibly lower that where it started? Is there a way to predict how much?

 

[Ajmassa]

So, if I wanted to increase the pH of a wine from say 3.30 to 3.40, I could do so by adding potassium carbonate. But then I would cold stabilize and the pH would go back down, possibly lower that where it started? Is there a way to predict how much?

You could do the antacid addition and then pull a sample for a cold soak 1st. Probably the only way to know for sure.