When to cold stabilize

[drainsurgeon]

I have read quit a few threads lately about cold stabilization, and have tried researching it further to find out what type of wines benefit from cold stabilization. To confuse me further I read one that after CS they actually added acid after because the pH got too high. Seems like chasing your tail somewhat. Just trying to understand the what and when. Tips please.

 

[cmason1957]

Whites and higher acidity reds tend to benefit most from CS. There are two main reason to CS 1) so that when you chill your whites, no tartartes fall out and "look bad" at the bottom of the bottle. 2) lower the acidity in higer acidity reds, since they tend not to be chilled when served.

If your wine is near the magic Ph of 3.6, the Ph may go up and may go down when you cold stabilize.

 

[drainsurgeon]

Whites and higher acidity reds tend to benefit most from CS. There are two main reason to CS 1) so that when you chill your whites, no tartartes fall out and "look bad" at the bottom of the bottle. 2) lower the acidity in higer acidity reds, since they tend not to be chilled when served.

If your wine is near the magic Ph of 3.6, the Ph may go up and may go down when you cold stabilize.

So, tartartes and tartaric acid are not the same? I thought "Diamonds" are tartaric acid falling out of the wine therefor making the acidity go down (pH up). If I've got that right, how could the pH go down?

Still not clear of exactly when to cold stabilize. Is there a magic pH number where one would say "OK, i'm going to CS this one for 3-4 weeks". Would you CS a skeeter pee that's at 3.0 pH?

I have yet to see the "Diamonds" in any of my chilled whites. I have mostly made kits over the years however. I made several whites from fruit and juice this summer and no diamonds yet.

 

[cmason1957]

I wouldn't cold stabilize a skeeter pee. There probably isn't enough tartaric acid in there for anything to drop out. Yes, the pH can go up and can go down with cold stabilization. I don't totally understand the chemistry that makes the difference. But I do know 3.6 is generally regarded as the tipping point ph.

 

[Johny99]

I'm going from memory and that is dangerous, but I believe the dianonds are potassium bitartrate crystals, a salt. They precipitate at colder temperatures. When doing so, they remove tataric acid. Of course if there isn't any tartaric acid, no salts. I also recall reading an article about seeding as well. So, since it is removing one of the acids it lowers TA referenced as tartaric but can affect pH either way depending on the various acid concentrations. Remember, TA is concentration of acid, pH is strength and different acids have different strengths. So, you could end up wanting to adjust acid after CS. Even tartaric

So, that said, I CS to stabelize and deal with or let the acid and pH be what they are. Why? Because I can't always control what happens to my wine after it leaves my cellar. E.g., my Christmas gift wine, 2011 Cab, road around in my truck at ~25 degrees most of a day.

 

[Stressbaby]

This is the way I think of cold stabilization.

T is tartaric acid. It has 2 hydrogens to give, and gives the first at average pH of 2.9, second around 4.3.

H2T <--> HT- <--> T--

The max amount of HT- is at pH of 3.6, right in the middle of 2.9 and 4.3. Whenever you cold stabilize, you are precipitating potassium bitartrate, or KHT. KHT removes HT- from the equation. The wine wants to maintain equilibrium.

So if the pH is above 3.6, you are on the right half and you can ignore the left half of the equation. Removing KHT as wine diamonds removes HT-, and to maintain equilibrium some T-- grabs a hydrogen, converts to HT- and raises the pH.

If your pH is low, you can ignore the right and only worry about the left half of the equation. Remove KHT and in order to maintain equilibrium H2T converts to HT- and H+, which means it gives up a hydrogen, decreasing the pH.

 

[drainsurgeon]

Thanks for all the responses. I've got some more reading to do obviously. Cheers!

 

[geek]

I bet you're still confused [emoji4][emoji4]

 

[drainsurgeon]

I bet you're still confused [emoji4][emoji4]

Just a little bit. I wish there was a simple rule, like whites below 3.5 would benefit and reds below 3.7. The #6(@4)7*{{^+=Mc2 formulas confuse me a bit.

 

[stickman]

If wine was just a mixture of acid and water, you probably could have a simple rule, but it's more complicated than that. Generally when you cold stabilize wine, if crystals drop out, the TA will decrease and the resulting wine should taste less tart even if the PH also drops a little. General rules have limitations and things like the potassium content of the wine, as well as the malic acid content, can make the outcome unpredictable. I have never tried it, but I see procedures for conducting cold stabilization bench trials, which is basically an overnight freeze of the wine, then thaw and pour the wine off of the crystals, and re-measure the TA and PH.

I make mostly reds and don't cold stabilize other than what occurs naturally in a 59F cellar during 9 to 12 months.

 

[zadvocate]

I have been wondering about this myself lately and it is very confusing. However as a general what I've read is that under 3.6 cold stabilization can lower your pH and above 3.6 cold stabilization can raise your pH. I mistakenly added too much acid at crush time. My cabs pH was 3.17 and TA 8 so I added pot BiCarb. The direction for that state to cold stabilize after adding. One day after my ph was 3.59 and TA 7.5. I have been cold stabilizing for a few days and will check the results later this week(ran out of sodium hydroxide). I will post if you like

 

[Stressbaby]

I have been wondering about this myself lately and it is very confusing. However as a general what I've read is that under 3.6 cold stabilization can lower your pH and above 3.6 cold stabilization can raise your pH. I mistakenly added too much acid at crush time. My cabs pH was 3.17 and TA 8 so I added pot BiCarb. The direction for that state to cold stabilize after adding. One day after my ph was 3.59 and TA 7.5. I have been cold stabilizing for a few days and will check the results later this week(ran out of sodium hydroxide). I will post if you like

Please do post back your results. How much did you use?

I just used potassium bicarb on a fruit wine. I have a blueberry that was undrinkably tart even after a preferment adjustment with calcium carbonate to 3.27. Postferment it was 3.07 and it was harsh, I suspect it has lots of malic. We did bench trials and arrived at 1.5g/L which got us to a point where it was easy to balance the wine with a pinch of sugar. The pH turned out to be 3.36. I've treated the batch and we're cold stabilizing, although it is not clear to me that cold stabilizing will have any effect given the lack of any tartaric in this wine. KHM is supposed to be pretty soluble in wine.

 

[drainsurgeon]

If wine was just a mixture of acid and water, you probably could have a simple rule, but it's more complicated than that. Generally when you cold stabilize wine, if crystals drop out, the TA will decrease and the resulting wine should taste less tart even if the PH also drops a little. General rules have limitations and things like the potassium content of the wine, as well as the malic acid content, can make the outcome unpredictable. I have never tried it, but I see procedures for conducting cold stabilization bench trials, which is basically an overnight freeze of the wine, then thaw and pour the wine off of the crystals, and re-measure the TA and PH.

I make mostly reds and don't cold stabilize other than what occurs naturally in a 59F cellar during 9 to 12 months.

Thanks stickman. The bench trial sounds like a good idea. Generally you feel reds do not benefit?

 

[stickman]

In my case, most of the reds I have made have required acid addition, due to low acid and high PH at crush. After acid addition, usually I see significant tartrate crystals dropping out during or after fermentation. Any acid addition I've made in the cellar after fermentation also has produced tartrate crystals, most seem to drop out over a couple months of storage at 59F, though at that stage I'm not in any hurry. I think there is a benefit for reds if your concern is lowering TA and tartrate stability, if you lower the temperature to drop out additional crystals you will get a corresponding drop in TA and reduced tartness, and an acid adjustment can be made, if needed, to correct taste before bottling. If crystals drop out in the bottle you will not have a chance to correct for the associated drop in TA, although maybe no correction is needed. It is a moving target, if the wine is a bit tart, crystals dropping may be desirable, and you can choose where they drop, in a tank or in the bottle. In my case, the cellar storage time is adequate to allow most of the precipitation to occur in the tank, with some minor crystals forming in the bottle over time, which doesn't really bother me. It should also be noted that bulk storage with lees contact, as well as gum Arabic addition before bottling, can also help to delay the formation of crystals in the bottle, if that remains a concern.