I’ve got a problem with my 2010 Sonoma county Cab and Zin. Both wines (from different appellations) are testing out with pH over 4 and TA at about 6.5. We’re just over halfway through MF, and are very concerned about longevity with these pH readings. I’m hesitant to add more acid, as the wines are already borderline tart.
I’m getting the feeling this it taboo in the wine making world, but an assistant wine maker at an unnamed but prestigious winery suggested adding sulfuric acid to lower the pH without jacking up the TA. I can’t find any information on sulfuric acid additions anywhere. Anyone willing to give me a straight answer?
I’ve read about Velcorin (to protect high pH wines - need a license?), ion exchange (complicated), mobile wine chemists (expensive), and cold storage (does it work?). I’d love some feedback - I’ve got about 130 gallons of wine with good potential at stake here and was hoping to barrel age for at least a year. Thanks in advance for the help!!
As far as I know, it’s not legal to add sulfuric to wine, even pharmaceutical grade. But if the wine is borderline tart, why add acid at all? As long as you keep the wine sulfured right after ML, who cares what the pH is? You’ll never meet a pH meter with a better palate than your own. You can have the wine tested and plated for all types of spoilage yeast and bacteria at any point in the barrel aging, right up until bottling. Then depending on what you see, you can investigate velcorin or sterile filtration. Good luck with your Cab and Zin.
Trent,
I never trust pH and TA numbers from wine still fermenting or in MLF. Retest when its done. Also, are you testing in your own lab? Changed your NaOH in awhile? Weak chemicals would give you high readings for TA. Sorry if that is a completely obvious suggestion but it seems strange to me that you have a fairly unusual combination in two different wines from two different places.
And I agree with Ed about going with your palate instead of your meter. But even if you were to add more tartaric after ML, a TA of 6.5 is not high by any means, so I wouldn’t worry about that going up a bit. Velcorin is added at bottling- the half life is measured in hours, so adding it before hand (even if you could), would not be of any use. It is meant to be a quick kill at bottling, when the wine will be in a closed system for the remainder of it’s life. If you added to a barrel for instance, you would get the quick initial kill, but that doesn’t mean something else wouldn’t be able to grow in your wine down the line.
I’ve gotta echo what others have said and ask some of the same questions:
Did you run the TA’s yourself or have them sent off to a lab? If yourself, did you degas the samples (since they are still going through ML, they should still be a bit gassy which will affect TA numbers)
How do you know they are ‘half way through’ ML? Lab tested? Paper chromatography?
What were the numbers like pre-ML? Did you get malic numbers? What kind of shift are you expecting?
It gets very dangerous to make wines ‘via the numbers’. Yes, high pH’s can lead to more issues during elevage, but as Ed points out (and he IS the king, by the way), you can monitor these things and take other measures later on if need be . . .
Hope that helps - but please provide a bit more info . . .
…and there are persistent rumors about a winemaker now very much in the natural wine camp adding phosphoric acid in similar situations in years past.
High pH/high TAs were a bit of a problem this year, especially on Pinots. Your best bet is to be able to blend out of the conundrum, if you have the raw material in the winery. Otherwise, AGP is advertising an acid (I think its the Fumaric – you eggheads know anything about this?) that hits pH without affecting TA much. I haven’t ever had to use it, so I can’t vouch for it. But its out there. If you do try it out, do bench trials to get your target amount then make up a couple of bottles and leave them for a few weeks.
your TA is probably inaccurate due to CO2; wait for ML to finish and be sure to degas your sample before measuring…we have the same problem and the difference is bigger than you think possible (recently a difference of >1 g/L between a degassed and non on a Chard)
adding these unusual acids (why not miuratic while you’re at it?) if you are pleased with the way the wine tastes is what we call mind-f’ing yourself, not to mention some are not legal. If it tastes right, leave it alone, keep your free SO2s higher (don’t be afraid to go high…the molecular portion of the sulfite is also the one with sensory implications) accordingly and pay some extra attention to these barrels at racking with sanitation. I deal with some high-pH, high-TA situations up here due to soil and warm nights, and if there is no inoculation with bad bugs, it follows that nothing will grow.
of all the pH-only remedies, I would probably look at the dialysis (the STARS system, which was originally developed to cold-stabilize without the “cold” part) first. Might be the most expensive, but probably also the most effective. If you try it, let us know how it goes…never used it.
finally, if you really want to mess with it, you could acidify it to an inch of its life to a reasonable pH and then de-acidify later. Again, a mind-f in my opinion, but a “logically” reasonable option.
The fumaric is ostensibly legal for wine production, at least that’s my recollection from the AGP catalog. Phosphoric is the main acid in Coca-cola, so I think it’s approved for food, not sure about wine. Bad for your teeth, though. Not in defense of their use, per se, but there are options out there if you’re backed in a corner. I suppose the biggest question re: bottling a high pH wine is what is your tannic structure like; a high pH, low tannin wine becomes real ugly real quick in the bottle (in my experience), but if there’s pretty good tannin, it can persist and age beautifully for some time. Often surprisingly so. In that light, I’d be more worried about the Zin than the Cab. It wouldn’t hurt to do several bench trials. Worst case scenario: you might learn what not to do.
I have never used fumaric and wasn’t terribly familiar with it, so I got out my textbook and found three things about it that might make me think twice about using it:
It supposedly has an “unusual” sensory profile, so bench trials as far as taste is concerned would be warranted. Not sure why it is unusual.
It does cause TA’s to rise. It doesn’t say by how much, but it didn’t make any claims that the rise might be less than other acids (it is a fairly sttrong acid, so it would stand to reason that it would be a bit less than tartaric).
Unless the add is enough to inhibit growth of microorganisms, it actually can be used as a carbon source. So that tells me that if you don’t whack the crap out of your wine, it might have the opposite effect than what you are looking for.
Thanks everybody for their detailed and speedy replies. I’m amazed how fast you all responded and with the caliber of your suggestions and resumes…
To answer Larry’s question:
We’ve conducted tests using our own pH meter and using paper chromatography tests for ML. Again, we think we’re a little over halfway thru ML.
Zin:
Pre ML TA 8.4g/l, pH 4.0, current = TA 6.6g/l, pH 4.05
Cab:
Pre ML TA 9.3g/l, pH 3.68, current = TA 6.95g/l, pH 3.91
Based on your suggestions, it looks like the best course of action will be to finish ML and retest making sure we have degassed. Our NaOH is pretty fresh, but we’ll run some tests to ensure the pH meter is calibrated correctly.
We’ll run bench trials utilizing various TA additions to arrive at the best variation for taste. Depending on our pH levels at that point, we have some decisions to make.
As a home winemaker, it doesn’t look we will have access to Velcorin if we choose to bottle w/ a high pH. Are there any more accessible alternatives?
Your other option is Lysozyme. The ‘main’ benefit of Velcorin is it’s very good at killing Brett. Velcorin can kill a wide variety of other things, but not nearly as effectively as Brett. Lysozyme will kill LAB (lactobacillus, pediococcus and similar) and can be purchased in home winemaker quantities. Lysozyme is basically a fining agent that you add to your barrel, usually a bit before bottling, but could be added at any time. An advantage to both Lysozyme and Velcorin is the higher the PH is the more effective they become. In fact, I believe Lysozyme has no effect below 3.8ph.
Clean barrels and frequent topping up also go a long ways toward keeping your wine clean. Also, if a piece of equipment touches one barrel, sanitizing it before it touches another barrel will help a lot. That way, if you develop a problem in one barrel you won’t be spreading it to your other barrels.
Maintaining higher sulfur levels for your topping wine will give you some extra insurance that your topping wine won’t get infected with something and spread it everywhere. Or if you want to, you could sterile filter your topping wine.
How much of this wine did you make, and how long do you plan to / hope to keep it around?
BTW, like Ian says, I too have heard rumors (which seem likely true) of the use of phosphoric acid, but have never spoken any commercial producer who admits to using it. The rumor is that phosphoric acid was very effective in lowering pH without a big jump in TA.
As a home winemaker, you may well be free to add acids which are not permitted in commercial wine.
As others have suggested, wait until ML is done and get good data, before you do sample additions.
Let me share the 2 most important lessons I have learned over the past 6 years making wines.
Rule #1. Listen to Ed Kurtzman
Rule #2. When in doubt, always refer to rule #1
In all seriousness, I would be topping every week. I top all of my wines each week, but in your case I would be especially diligent. Hauling out the Velcorin Death Star will probably not be a possibility for 2 barrels of wine when it is time to bottle, but you are going to have to filter.
If the wines taste tart, I wouldn’t be adding anything. How good is your analysis? Any possibility you have bogus numbers?
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