Potassium Carbonate vs Potassium Bicarbonate post fermentation.

[Tnuscan]

Which do you prefer/use after fermentation and why? Most articles speak of Pot. Bicarbonate, but not as much info on Pot. Carbonate.

 

[geek]

I have potassium bicarbonate and what I use, if needed, because it's what I have on hand. It requires cold stabilization afterwards.

 

[Tnuscan]

I also use Pot. Bicarbonate, but I notice on many posts that some use the potassium carbonate. I was hoping myself and others might could see some easy to understand reasons for choosing/using each.

 

[Boatboy24]

I use Carbonate because that's what the MoreWine manual said to use. Additionally, they don't even sell Bicarbonate.

 

[Tnuscan]

I saw this on www.brsquared.org.

Approximately 0.67 g of potassium bicarbonate is reported to practically reduce the TA by 1 g/l (2.53 g reduces 1 US gal. by TA of 0.1 %; 3.03 g reduces 1 Imperial gal. by TA of 0.1 %).


Approximately 0.92 g of potassium carbonate\ is reported to practically reduce the TA by 1 g/l (3.49 g reduces 1 US gal. by TA of 0.1 %; 4.19 g reduces 1 Imperial gal. by TA of 0.1 %) and raises pH by between 0.2 to 0.25 units.


The difference between the two are the grams it takes to reduce the TA.

Exception being that potassium carbonate raises pH by between 0.2 to 0.25units.

 

[geek]

I remember someone saying or I read somewhere that potassium bicarbonate is 'healthier' than potassium carbonate (or maybe calcium carbonate?).

 

[ibglowin]

The Carbonate is more reactive than the Bicarbonate as the Bicarbonate already has one (H+) so it can only accept one more (H+) where as the Carbonate can accept 2 Protons (H+) thus making it "more reactive". Either will work fine for wine making adjustments. You have risk with the Carbonate that you may add too much and lower your pH too much right off the bat so use extra caution. I have used Acidex which is the bicarbonate form and found it to be extremely efficient at lowering pH.

 

[garymc]

I remember someone saying or I read somewhere that potassium bicarbonate is 'healthier' than potassium carbonate (or maybe calcium carbonate?).

It might have been sodium bicarb that is considered less healthy.

I'm wondering if there's any difference in the taste of the wine after treatment with potassium bicarb vs potassium carb. Twice as much potassium left with the bicarb? Some people take potassium supplements. But does it leave a bitter, salty, or metallic taste?

 

[Tnuscan]

It might have been sodium bicarb that is considered less healthy.

I'm wondering if there's any difference in the taste of the wine after treatment with potassium bicarb vs potassium carb. Twice as much potassium left with the bicarb? Some people take potassium supplements. But does it leave a bitter, salty, or metallic taste?

Sorry, I just noticed your second paragraph.

Is this what your refering to: Potassium carbonate can react with malic acid (though as stated above, tartaric takes precedence) to form potassium bimalate. However, potassium bimalate is soluble in wine and will not (or may be difficult to) precipitate out.

Potassium bi/carbonate should be used carefully due to additions increasing must/wine pH (by the inevitable presence of increased potassium ions). Bench testing may be conducted on samples to ensure that the desired level of deacidification does not cause a pH shift beyond acceptable levels.

Either chemical is usually added to the entire batch, carbon dioxide is given off while the batch is well mixed, and cold stabilization is conducted several days later to encourage precipitation. The deacidified liquid can then be racked off the potassium bitartrate salt lees. This deacidification is often conducted after fermentation, but should be used before cold stabilization so that full precipitation is achieved.


I've read conflicting articles on the pot carbonate. I have both but at the moment I'm using the bicarb for my additions, then cold stabilizing.

I've read if you don't do CS the potassium will not fall out, and can ruin your wine. But I myself, have not tried the experiment to prove this true or false.

"As with tartaric acid, for the purpose of testing for the proper additions of potassium carbonate, make a 5% solution. Put one litre of wine into a refrigerator and chill to about -3 or -4°C. Set up a few glasses with 100 ml of the chilled wine. Using one as a control, add 1, 2, 3, etc, mls. of the solution which will be the equivalent of 0.5, 1.0, 1.5, etc, g/l. Refrigerate for two hours or so stirring regularly - 7 or 8 times. Let the samples warm up to cellar temperature and taste to determine the amount to add to the batch. It is necessary to taste the wine after the potassium carbonate has been added to the glasses in order to determine whether there is a resulting flabby taste. I have found that some wines, particularly aromatic wines lose their crispness when potassium carbonate is used even in very small amounts".

 

[garymc]

All I can add is to ask more questions. I see you're in Tennessee, where you might be seeing some muscadines. That's what I use for most of my winemaking. What I make that is not muscadine, is elderberry, blackberry, and aronia. In other words, all this research on vinifera and labrusca and hybrid wines and their tartaric acid may have little relevance. I don't know if any of these things that I use have more or less tartaric acid than "normal" grape wine. I do know that muscadines and blackberries are highly acidic, elderberries are very low in acid, and I suspect, but have no specific information that aronia is not very acidic. My best efforts in acid adjustment has been to blend elderberries and muscadines right from the start before pitching. Oh, and I've done the same with blueberries and blackberries or elderberries and blackberries.

 

[NCWC]

Calcium bicarbonate must - pre and during fermintation and for larger reduction in ph if smaller ph reduction is needed potassium will work here too
potassium carbonate post fermentation to touch up the wine
both will precipitate out and need racking