Calcium Carbonate vs. Potassium Carbonate vs. Potassium Bicarbonate

[jaxn]

I've used Calcium Carbonate (CaCO3) on a few batches already to raise pH; few times to restart a stuck fermentation and another to preemptively keep one going. It seems to do the trick, but I have yet to taste test any of them to see if it leaves a chalky taste.

After reading hightest's FAQ about Potassium Carbonate (K2CO3), I started looking around for suppliers. It seems like wine shops carry only Potassium Bicarbonate (2KHCO3). There are other vendors that carry potassium carbonate (photography and chemistry suppliers), but not wine and homebrew shops.

Is potassium bicarbonate a fair substitution? Do the same benefits mentioned in hightest's FAQ apply? I am not sure about putting something from a photography equipment vendor in my mead.

I got a 60lb bucket of clover honey that seems particularly acidic, so I definitely feel the need to buffer somehow.

 

[MedsenFey]

Calcium carbonate if used with reasonable amounts will not cause a problem, however, I prefer to use the potassium products because potassium is an important ion that the yeast need nutritionally to help balance the electochemical gradient across the cell membrane created by a low pH. All those H+ ions on the outside of the cell get balanced by K+ ions on the inside. This helps the yeast to function better even if the pH is not raised as much.

Potassium carbonate is a stronger base than the potassium bicarbonate, and can result in more violent chemical reactions. The bicarbonate is less caustic and classified as a GRAS (generally regarded as safe) food additive by the FDA. This is why you'll find the bicarbonate at most brewing retailers rather than the carbonate. Either one will work.

If you don't have either of those available, another way to buffer your meads is using Cream of Tartar (potassium bitartrate). Most grocery stores carry it. Roger Morse was a proponent of it recommending 4 grams per gallon be added at the beginning of fermentation.

Medsen

 

[jaxn]

Wow. Great respsonse. Thanks.

I don't have any potassium bicarbonate at home, but I definitely have some cream of tartar. However, I'm only a 30-minute drive from Rebel Brewer.

4g/gallon of cream of tartar, you say?

 

[vulture1963]

A Google search will uncover sources if you wish. Potassium carbonate is great - little to no taste, and very effective.