Unusually High pH?

[kenthelawyer]

I made a batch of California cab in 2019 and followed the standard process - ferment, MLF in barrel, racking, etc. I barreled it for two years in oak and am preparing to bottle. I tested it in mid-2020 and in Dec 2021 - both tests showed a very high pH (3.9). Online articles say it's hard to protect with sulfite at that pH level (my free SO2 is pretty low ~4ppm), and the amount of sulfite to be added based on charts online seems ridiculously high. TA is 6.5 g/l. It's a little flabby, but a reasonably OK wine for my first attempt I think. I don't want to oversulfite and ruin it entirely.

I followed the same process for my 2021 cab and the pH is 4.0. Again, super high. But it's delicious so far (I think it's pretty high octane and possibly has some residual sugar).

Does adding acid make sense? To decrease by 0.5 pH for my 60 gallons of 2019 cab would require about a kg of tartaric acid. Seems like a strange thing to do to a wine.

Open to advice.

 

[sour_grapes]

It's a little flabby, but a reasonably OK wine for my first attempt I think. I don't want to oversulfite and ruin it entirely.

I would absolutely try a bench trial adding some tartaric acid. Mostly to see if it improves the taste. You may get the pH a bit lower AND get a better wine.

Personally, I wouldn't chase the pH at the risk of harming the wine's taste.

 

[winemaker81]

I agree with Paul. Keep in mind that your pH meter will not be drinking the wine, you will. I say that tongue-in-cheek, but the statement is accurate.

Regarding SO2, the rule of thumb is 1/4 tsp K-meta per 5 gallons. If you think the SO2 will be low, increase that as much as 50%.

 

[sour_grapes]

I would absolutely try a bench trial adding some tartaric acid. Mostly to see if it improves the taste. You may get the pH a bit lower AND get a better wine.

Personally, I wouldn't chase the pH at the risk of harming the wine's taste.

I should state explicitly that, by "bench trial," I mean a small amount. Try comparing three or four glasses with different acid additions (and no added acid in one of them).

 

[kenthelawyer]

Super helpful, fellas. I will try that. Much appreciated!

And I looked up "bench trial" just to be sure. I'm a lawyer and bench trial has a slightly different meaning in my work.

Looking forward to any excuse to taste more wine!

 

[kenthelawyer]

And is there a pH meter that you recommend? I've been driving about 90 minutes to testing facilities (I live in the SF Bay Area), and while it's quite fun to go to wine country, I think it may be a more efficient use of my time to have the capability at home. And it will be much less expensive, since every time I drive up there I wind up buying a case of something I don't really need or have room to store. Life is tough.

Also, do you typically try to target a TA level? A friend and fellow amateur winemaker religiously targets a TA level in her wines (less focus than pH). Not something I've focused on before.

 

[ChuckD]

This came up a few weeks ago. Several here use the Apera pH 60. I have it and it’s a good meter for the price ~$80. It includes a nice case and laminated instructions.

ETA. It has a replaceable sensor too.

 

[Chuck E]

I use a Milwaukee 102

 

[BarrelMonkey]

I use a Milwaukee 102

Second vote for the Milwaukee 102, I bought one last year and it's been great so far. There are several threads here on the merits or otherwise of different pH meters:

Recommendations for new pH meter
The battle of the pH meter

And regarding running a bench trial: I recently did this for my 2021 pinot noir. After ML, the pH and TA came out to be 3.70 and 5.55g/L respectively. This is right on the edge (high pH/low TA) of what I would consider OK, allowing for the fact that this is a relatively 'big' style of pinot noir. I set up a double blind bench trial with the base wine and two levels of tartaric acid addition, the highest being 1g/L which would be expected to shift pH by ~0.1 unit. I made my additions and left the samples for an hour before tasting. Two tasters independently identified the wines in the right order (i.e. no addition, low addition, high addition) and both agreed that the unadulterated wine was the best. It's possible that 1 hr wasn't enough time to integrate the acid addition, but both of the acid-modified wines tasted disjointed, to the point of distraction. The goal of adding acid was to brighten up the fruit in the wine, but interestingly it was the original untreated sample that tasted the brightest and fruitiest. So I'm going to leave it as is, and monitor carefully as the year progresses (I'll probably bottle around August).

 

[sour_grapes]

Delete. I missed an important word!

 

[crushday]

(my free SO2 is pretty low ~4ppm)

With a wine at 3.9 pH and only 4ppm FSO2, I'll add to @sour_grapes suggestion to bench trial TA additions - You NEED to sulfite the wine. The commercial legal limit for free SO2 is 300ppm - which gives some people a headache. It's a common criticism of red wine... You could get away with racking and adding kMeta to 70 ppm with no problem w/o TA additions. You probably already have such a chart, but here goes:



**chart image courtesy of @Johnd

 

[Rice_Guy]

Also, do you typically try to target a TA level? A friend and fellow amateur winemaker religiously targets a TA level in her wines (less focus than pH). Not something I've focused on before.

Welcome to WMT. Any pH meter is better than none. The digital electronics just works and the bulb needs to be clean and moist/ not dry.
one targets pH to force the chemistry (pKa) to work as Crush noted and pH operates as a fence which excludes several families of microbes from growing. ,,,, ie fermentation works better. ,,, In many foods pH is a control point.
one targets TA on the finished wine to produce balanced flavors, mainly a finished wine function. Do you like to drink dry or sweet?

A guideline for where to balance TA on wine;
after club contest this year I collected eight first place wines which are the red triangles
View attachment 81200
The sample set "cloud" is primarily commercial wines, with some collected in the vinters club and here on WineMakingTalk
NOTE: TA is one of several quality traits which a first place wine has as absence of flavor defect, appropriate aroma for the variety and clarity , , , etc.
NOTE 2: this is an easy test, if ya'll are interested in your wine ,,, PM me

 

[managuense]

Few things to add to this...

Firstly, adding acid this close to bottling is well, less than ideal for sure. All the notes above regarding taste and disjointedness of acid additions are very normal in wine and usually get better over time. The hesitancy to add acid earlier in the game because of this leads to this very issue. If you are looking to adjust your pH this close to bottling I might recommend doing lactic acid trials over tartaric acid for 2 reasons. Lactic acid won't have the same impact on the texture and flavor of your wine. . The other problem with adding Tartaric this late in the game is that you will greatly destabilize your wines cold stability. This will lead to tartrate formation in bottle. The downside however is that lactic acid isn't going to be as pH reactive as tartaric...Maybe not a big deal to you just drinking it at home but thought it was worth mentioning so you're not surprised later.

FS02: all free S02 is not created equal, in that x ppm Free will not have the same antimicrobial or antioxidant properties in wines with a lower than x ppm Free S02 at lower pH. Proper wine health is obtained by setting your wines in a pH spectrum that both tastes and smells great but also allows your S02 more bang for its buck. As someone stated above you want to limit the pH spectrum of what bugs will be allowed to live and even flourish in. The higher the pH the more FS02 you will need to control microbes. A better way of looking at FS02 is in the molecular range. This range takes into account both your pH AND your FS02. For instance most professional winemakers make decisions about where they want their final FS02 by understanding what bugs are in the wine through a micro scan and controlling accordingly with the right amount of molecular S02. 0.5-0.8 is the typical range we look at. 0.5ppm molecular Free S02 will control bugs like oenococcus (wild ML bugs) but will not control things like Acetobacter (bugs that produce VA) which require 0.8 just to slow them down. All of the various spoilage organisms in wine have a known molecular range that will slow or even kill their progress. Some however require such a high molecular range organisms like Brettanomyces and Lactobacillus require molecular ranges over 1.0 ppm to slow the growth. In those cases filtration and S02 are needed as 1.0ppm molecular S02 will destroy or burn aromatic compounds in the wine. Heres a link to a molecular S02 chart you can look at: http://srjcstaff.santarosa.edu/~jhenderson/SO2.pdf (sorry I'm not good at formatting things on here).

I would encourage you moving forward to take a proactive approach to this problem earlier in the game. Corrections to your chemistry in juice phase ALWAYS yield better results without compromising the smell or taste of your wine. My own method is to get the juice as close as possible predictively before I start primary. I run analysis again after primary and make any small tuning adjustments before I inoculate for MLF. The resulting wines have both proper chemistry health and taste and smell beautiful.

If you need help with how to predict your acid shifts as well as pH feel free to reach out I can provide you with more info. Good luck and don't let this one get ya down, I am sure the wine will be great

Cheers!

 

[stickman]

I just wanted to point out that care needs to be taken when following the molecular SO2 chart with high pH wines.

The following was quoted from the outdated 2005 Gusmer Managing SO2 document above:

"In general, we suggest a lower molecular SO2 for reds than for whites, perhaps around 0.4-0.6 ppm at bottling. Wines with higher pH levels, red or white, may require too high a total SO2 level to achieve desired free SO2 levels. Rather than have excessive bound SO2 (which may give a “chemical” taste), it is best to rely on a combination of factors, including susceptibility to spoilage. Some pH problems can be relieved by adjusting the pH downward with tartaric acid."

What is also interesting is that the above Managing SO2 article from Gusmer indicates "Adapted from: Enology Briefs I (#1), Feb/Mar 1982. University of California Cooperative Extension". Clark Smith was involved with that publication as noted in the references below, and he made a revision in 2012.

Sulfur Dioxide Basics Revisited, Wines & Vines March 2012 by Clark Smith is the article I referenced above; you can read the full article if desired, though it may be behind a pay wall. There are a lot of details, but didn't want to reprint the entire thing here, a few items are noted below.

Clark indicates in the article:

"Thirty-two years ago my first published piece, printed in the inaugural issues of the University of California, Davis, Extension’s Enology Briefs (1)(2), concerned the basics of conventional SO2 management. A table I worked out with pencil and paper in a Shields Library basement can still be found tacked up on winery lab walls throughout the United States. There are omissions I have since regretted, and it is high time for a rewrite. The most important omission in my 1980 article was to point out the folly of applying the table to high-pH wines."

"In low-pH winemaking, we stress the role of molecular sulfur dioxide to control the growth of microorganisms. Since its effectiveness as an inhibitor is greatly lessened at high pH, it is more sensible to forget about molecular SO2 in this zone and instead regulate free SO2 (FSO2)."

"Free SO2, which is substantially all bisulfite, should be maintained to combine with H2O2 as it is formed as a side product of chemical oxidation of diphenols. The reaction of sulfites and peroxide is the fastest reaction known to chemistry, and it may be relied upon to prevent the formation of aldehyde from ethanol oxidation. Since SO2 is depleted by this action and by aldehyde binding, it must be measured by aeration/oxidation and maintained at a reasonable level (20-30 ppm) throughout aging."

References

(1.) Enology Briefs, University of California, Davis, Extension, Vol. 1 No. 1 (1980)

(2.) Enology Briefs, University of California, Davis, Extension, Vol. 1 No. 2 (1980)

(3.) Smith, Clark. Studies on Sulfur Dioxide Toxicity for Two Wine Yeasts In a Wine like Medium and the Mechanism of Cell Death. (1982)


Read more at: https://www.winesandvines.com/columns/section/92/article/97777/Sulfur-Dioxide-Basics-Revisited
Copyright © Wines & Vines

 

[managuense]

I just wanted to point out that care needs to be taken when following the molecular SO2 chart with high pH wines.

The following was quoted from the outdated 2005 Gusmer Managing SO2 document above:

"In general, we suggest a lower molecular SO2 for reds than for whites, perhaps around 0.4-0.6 ppm at bottling. Wines with higher pH levels, red or white, may require too high a total SO2 level to achieve desired free SO2 levels. Rather than have excessive bound SO2 (which may give a “chemical” taste), it is best to rely on a combination of factors, including susceptibility to spoilage. Some pH problems can be relieved by adjusting the pH downward with tartaric acid."

What is also interesting is that the above Managing SO2 article from Gusmer indicates "Adapted from: Enology Briefs I (#1), Feb/Mar 1982. University of California Cooperative Extension". Clark Smith was involved with that publication as noted in the references below, and he made a revision in 2012.

Sulfur Dioxide Basics Revisited, Wines & Vines March 2012 by Clark Smith is the article I referenced above; you can read the full article if desired, though it may be behind a pay wall. There are a lot of details, but didn't want to reprint the entire thing here, a few items are noted below.

Clark indicates in the article:

"Thirty-two years ago my first published piece, printed in the inaugural issues of the University of California, Davis, Extension’s Enology Briefs (1)(2), concerned the basics of conventional SO2 management. A table I worked out with pencil and paper in a Shields Library basement can still be found tacked up on winery lab walls throughout the United States. There are omissions I have since regretted, and it is high time for a rewrite. The most important omission in my 1980 article was to point out the folly of applying the table to high-pH wines."

"In low-pH winemaking, we stress the role of molecular sulfur dioxide to control the growth of microorganisms. Since its effectiveness as an inhibitor is greatly lessened at high pH, it is more sensible to forget about molecular SO2 in this zone and instead regulate free SO2 (FSO2)."

"Free SO2, which is substantially all bisulfite, should be maintained to combine with H2O2 as it is formed as a side product of chemical oxidation of diphenols. The reaction of sulfites and peroxide is the fastest reaction known to chemistry, and it may be relied upon to prevent the formation of aldehyde from ethanol oxidation. Since SO2 is depleted by this action and by aldehyde binding, it must be measured by aeration/oxidation and maintained at a reasonable level (20-30 ppm) throughout aging."

References

(1.) Enology Briefs, University of California, Davis, Extension, Vol. 1 No. 1 (1980)

(2.) Enology Briefs, University of California, Davis, Extension, Vol. 1 No. 2 (1980)

(3.) Smith, Clark. Studies on Sulfur Dioxide Toxicity for Two Wine Yeasts In a Wine like Medium and the Mechanism of Cell Death. (1982)


Read more at: https://www.winesandvines.com/columns/section/92/article/97777/Sulfur-Dioxide-Basics-Revisited
Copyright © Wines & Vines

All relevant and good information. This should have been my conclusion in the FS02 portion of my topic, well some of it.
The ultimate point I was trying to make, and perhaps not doing the best job of, was not to make wines that require 75-100 ppm FS02 in the first place. Looking at the chart I linked shows what massive shifts in FS02 that are required to protect high pH wines vs low pH wines.
So yes, I would be very uncomfortable having 75ppm FS02 in any wine I make. I would be equally uncomfortable with making a wine with a 4.0 pH as well.
I don’t know many people who would pay much attention to this scale when making high pH wines. However I find it oddly common that people that make low PH wines do not follow it either but with the opposite error. Some aromatic whites for example with low pHs have no business being bottled at 25-30ppm FS02, yet I see it all too often because 15-18ppm FS02 just doesn’t feel like enough (according to the chart… I’m just giving an example).
I don’t recall ever bottling a wine with more than 35-36ppm FS02. I would think if you planned to consume a high pH wine with that FS02 in a reasonable short aging window it would probably be ok.
Thanks for pointing this out though stickman!