Calcium Carbonate - Lime Flour?

[Goatherd]

I'm wanting to de-acidify a grape must, and wondering if I can use the same type of Calcium Carbonate powder I already have 25kg of.

I found info on winemaking calcium carbonate saying it is powdered chalk. This bag says it is calcium carbonate, powdered lime. Is there a difference?

It is milled limestone flour, intended to be mixed with water or food as a dietary supplement for dairy cattle.

It is a new bag only opened for one use and then closed up so it is clean, and it looks like a very fine off-white powder.

I've just bottled last year's red wine and wish it was less acidic.
Meanwhile the grape vine is heavy with ripe grapes and I need to do the next batch, so I'd like to treat the must for acidity if I can.

But, I'd like to avoid going into town for new supplies - the covid wave is peaking right now in there.
Is the calcium carbonate I have any good do you think?

 

[cmason1957]

I would think it is probably fine, but before you use it, try adding just a small amount of sweetening to your wine. I am guessing you don't have a PH meter to determine what Ph and Ta you might be dealing with, just the taste. It might lead to better results if you had some numbers to back up what you are doing, how much calcium carbonate you plan to add. adding to much can lead to a chalky taste, I believe.

If you decide sugar helps things out, you can just add a known amount to every bottle you open to cut back the harshness.

 

[Goatherd]

I would think it is probably fine, but before you use it, try adding just a small amount of sweetening to your wine. I am guessing you don't have a PH meter to determine what Ph and Ta you might be dealing with, just the taste. It might lead to better results if you had some numbers to back up what you are doing, how much calcium carbonate you plan to add. adding to much can lead to a chalky taste, I believe.

If you decide sugar helps things out, you can just add a known amount to every bottle you open to cut back the harshness.

In fact I did backsweeten when I bottled, I think if I did more it could be a bit too heavy on the sweet ... but I will try a sample with a little more and see.

I'm about to harvest the next season grapes though, and it is this fresh batch I'd be using the calcium carbonate in.

I do have a PH probe, but it is being used for hydroponic solutions. I hesitate to sterilise it to use in wine, as I don't know what the chemicals will do to the electrolyte in the probe. It's prone to being un-calibrated by weird solutions.

As well as the flavour, I noticed a lot of tartaric crystals growing in the wine at each decanting which is why I thought, next time I'll deacidify right at the beginning when I start the must.