Reducing Acid

[Boatboy24]

I'm still looking into what to do about my acidic Cabernet Sauvignon. A few options are available, and I'm leaning toward simply trying to blend it away. But of the 3 varietals I did last fall, two are really, really good right now. This cab is good as well, if you can get past the acidity. I was doing a little reading and came across this article in WineMaker:

https://winemakermag.com/547-phiguring-out-ph

In it, Pambianchi states: Other products, such as ACIDEX®, can be used to increase pH by reducing tartaric and malic acids in approximately equal parts by precipitating them in their salt forms — a chemical process known as double-salt precipitation. The advantage of these products is that the precipitated solids can be separated from the wine within 30 minutes. Follow the manufacturer’s instructions as each product may have handling differences.

I was intrigued by this. 1) because I've tried MLF twice now, with no success, so reducing malic as well as tartaric is an attractive option. 2) because I think if I can reduce the acidity in this wine without taking away anything else, I'd have a great wine on my hands that would be great in a blend, or on its own.

Has anyone ever used Acidex? What was your experience? Aside from trying to blend it away, any other thoughts on adjusting the acidity of this wine? I recently measured pH at 3.25.

Thanks for your input.

 

[Johnd]

Jim:
Not being familiar with the product, but always up for a learn, I did some research and found the following, which I pasted in here for you:

"ACIDEXâ: This so-called double salt of calcium carbonate, in theory, reduces both tartaric and malic acids equally. Before fermentation a portion of the juice is treated wherein all the acid is removed and then added back to the rest of the juice. Do not use this procedure on wine, as the portion treated will have a pH close to 8.0 and the wine will oxidize irrespective of its SO2 content. Do not be alarmed at the dark brown colour of the deacidified juice; fermentation will clear it up. It is advisable not to use any SO2 in the treated juice, otherwise the colour may become "fixed" or bound. In order to use AcidexÒ effectively, it is necessary to consult the Desired Acidity table below.

Unlike the following carbonates, the juice must be stirred into the AcidexÒ in order to reduce the malic acid as well as the tartaric acid. In order to reduce the malic acid, the pH must be higher than 4.5, preferably above 5.0, during the entire process, so stir the juice in slowly. (See Explanations for Acid Reduction p. 4) Some winemakers have added AcidexÒ to the juice or the wine and observed an acid reduction, but only the tartaric acid has been reduced. The same result could have been obtained by using one of the carbonates described below at a fraction of the cost. "

If I'm understanding, this product is for use with juice/must prior to fermenting if you want to reduce tartaric and malic. Looks like you take a portion of your juice out, deacidify it, and put it back into the vat prior to fermentation, thereby raising your Ph with your very own deacidified juice. When added to juice or wine, it apparently only reduces the tartaric acid.

Just my two cents, I know somebody will come along, having already conquered this problem, and add something valuable.

 

[Boatboy24]

Thanks John. Looks like I'm too far down the road to use Acidex.

 

[ceeaton]

Jim, did you try doing any cold stabilization? Just curious, didn't see it mentioned on your other thread. Would be curious if you did it how much it affected the TA and pH.

 

[Boatboy24]

Jim, did you try doing any cold stabilization? Just curious, didn't see it mentioned on your other thread. Would be curious if you did it how much it affected the TA and pH.

Cold stabilizing a low pH wine can actually make it more acidic. While you're precipitating out tartaric acid, you also remove potassium, which buffers the pH. By doing that, you actually lower your pH (if I understand the process correctly). It's a new concept to me, but one that I've read enough about to be wary of cold stabilizing this particular wine.

Cold Stabilization

Cold stabilization is tricky! The procedure involves placing the wine in cold storage at a temperature between 25° and 40° F (-4° and 4° C) for a minimum of three weeks and then racking it. This has the effect of precipitating the tartaric acid as potassium bitartrate salt *— the tartrate crystals you find at the bottom of a bottle of wine that you forgot and left in the fridge for too long — which decreases acidity and hence TA. However, remember that potassium contributes to a higher pH. When it precipitates during cold stabilization, it then lowers the pH. This effect actually happens at a pH of 3.65 (use 3.6 if you have a 0.1 precision pH meter) or lower because of the relative concentrations of tartrate and potassium in the wine. At a pH of 3.65 or above, cold stabilization will actually raise the pH.

 

[Boatboy24]

I'm thinking about my post above even more now and the two EP kits I did a couple years ago. Both were cold stabilized and both have a tartness that I feel shouldn't be there. I did CS because I wanted to precipitate the crystals before I bottled. I may have done more harm than good in doing so.

 

[ceeaton]

Thanks Jim. That actually does make some sense (chemistry wise) and I had forgotten your Cab pH was rather low (like 3.25 or so?). Hope someone chimes in here with a solution so I can add a new tool to my toolbox.

Edit: This is an interesting article. Post ferment acid reduction is towards the end of the article:

http://wine.wsu.edu/research-extension/2010/10/managing-high-acidity/

 

[berrycrush]

I once used KHCO3 then cold stabilized a batch which I added too much tartaric acid. It worked well.
What is you current PH and TA? just curious.

 

[ibglowin]

Just be careful if you do go this route (Double Salt) and make sure to rack it ALL off. Worst (commercial no less) wine I ever tasted had been treated this way and they did not get it all out somehow. Tasted like a salty cabernet. Absolutely horrible.

 

[Boatboy24]

I once used KHCO3 then cold stabilized a batch which I added too much tartaric acid. It worked well.
What is you current PH and TA? just curious.

At last check, pH was 3.25. I tested TA prior to fermentation and got .65. But my pH meter wasn't working at the time so I was going by the color change. I may have been off.

I've had no luck getting MLF to complete either with VP41, or CH16. I suspect the pH is the reason.

 

[Boatboy24]

OK, I have a 1 gallon carboy of the misbehaving Cab. I think I'll experiment on that first to see how it works.

Next question: what's the shelf life of potassium carbonate? I have a 2 year old, unopened packet.

 

[stickman]

If it was sealed and is still a loose powder it is probably fine, although you can test activity by adding a small amount to some vinegar which should cause a visible reaction.
Once you increase the PH of the wine it may cause the MLF to proceed if you haven't added too much sulfite.

 

[Boatboy24]

If it was sealed and is still a loose powder it is probably fine, although you can test activity by adding a small amount to some vinegar which should cause a visible reaction.
Once you increase the PH of the wine it may cause the MLF to proceed if you haven't added too much sulfite.

I haven't added sulfite yet. I was thinking the same thing about MLF.

 

[Boatboy24]

Well, that was interesting. I siphoned off about 4oz of the cab into a measuring cup and added ~4g of potassium carbonate (by my estimates, this would get me to a pH of 3.35). There was a color change and a very noticeable difference in the nose. The color became almost blue-green. When I mixed that sample back in with the gallon, there was no noticeable color change. I'm hoping what I saw was just the result of a proportionally large amount of potassium carbonate. I put the gallon in the garage and will let it sit for a few weeks, then rack it off the sediment and compare to the 6 gallon carboy that has not been treated. Fingers crossed.

 

[GreginND]

I'm hoping what I saw was just the result of a proportionally large amount of potassium carbonate.

Yes, you are right. The anthocyanins that provide color are very pH sensitive. The pH of your small batch was very high. Once mixed in the bulk, everything should balance.

 

[Tnuscan]

Well, that was interesting. I siphoned off about 4oz of the cab into a measuring cup and added ~4g of potassium carbonate (by my estimates, this would get me to a pH of 3.35). There was a color change and a very noticeable difference in the nose. The color became almost blue-green. When I mixed that sample back in with the gallon, there was no noticeable color change. I'm hoping what I saw was just the result of a proportionally large amount of potassium carbonate. I put the gallon in the garage and will let it sit for a few weeks, then rack it off the sediment and compare to the 6 gallon carboy that has not been treated. Fingers crossed.

Any new info on this procedure?

 

[Boatboy24]

Any new info on this procedure?

It worked! See post #72. Going back to my notes, pH is now 3.63. So the 'experiment' went exactly as it should have.

http://www.winemakingtalk.com/forum/showthread.php?t=51136&page=8