Sauvignon Blanc high pH

[Denden5136]

I picked 160 lbs of Sauvignon Blanc this weekend. The harvest is a bit late. The Brix came in at 27. The grapes were on the "done" side, but were from a good, clean vineyard and the fruit looked really good.

Got everything crushed and pressed in a couple hours and checked the pH - 4.1. I thought my pH meter must be off, so I recalibrated....4.1. I then used the little test strips - similar. The TA also came in very hight at 9, so I tested again and it came in at 8.8.

I have adjusted SO2 up to 80ppm, which is still low for the pH, but will hold there until the primary slows before testing FSO2 later this week and making adjustments.

So high pH with high TA. This leaves little wiggle room. Suggestions?

On the good side, the aromas are amazing and the fermentation has been going well. I am keeping the fermentation temp below 70.

 

[CDrew]

It's going to come down to how confident you are about your TA titration.

The fruit was over-ripe but since it tastes good, all is well. I'd make an acid addition. I don't know if your measurement is right or not, but your TA sounds high, like double what it should be.

If fermentation is ongoing, why the SO2 additions to 80ppm? With nice clean fruit you don't need to add any sulfite until fermentation is over.

Does it taste overly sour? If not, I'd probably add 2-3 gm/L of Tartaric. That should get you to roughly pH 3.8 which is a bit better place to be. Excess tartaric acid will also fall out of solution over the next winter.

 

[ibglowin]

How did you determine TA?

 

[Denden5136]

It's going to come down to how confident you are about your TA titration.

The fruit was over-ripe but since it tastes good, all is well. I'd make an acid addition. I don't know if your measurement is right or not, but your TA sounds high, like double what it should be.

If fermentation is ongoing, why the SO2 additions to 80ppm? With nice clean fruit you don't need to add any sulfite until fermentation is over.

Does it taste overly sour? If not, I'd probably add 2-3 gm/L of Tartaric. That should get you to roughly pH 3.8 which is a bit better place to be. Excess tartaric acid will also fall out of solution over the next winter.

I upped the SO2 because of the high pH - so much gets absorbed there is little left.

The wine actually tastes balanced, which is what surprises me. This is why I tested twice on the TA. I do want to up the acid to bring it down to the 3.8 range, which is still a bit high for whites, but at least sounds more stable.

This is my first time with white wine after several years with reds. What an adventure!

 

[Denden5136]

How did you determine TA?

With the TA test kit I always use. 100ml distilled, 6 drops phenolphthalein, 5ml must then 0.1 NaOH solution. I tested my Cab Sauv last week and Zin a week earlier and the tests were accurate, so the solution should be good. I am scratching my head on TA this high for grapes this late. I expected something in the 6.x range for SB this late.

The only difference, is that I am used to reds, so the solution turns blue/grey, where with whites it goes pink. The endpoint (pink) was at 6.0ml for the first test and 5.9ml for the second. Is there anything different for whites?

 

[ibglowin]

While phenolphthalein will give you a decent number I would test again using your pH meter to detect endpoint more accurately (ph=8.2)

Here is a good guide:

https://morewinemaking.com/web_files/intranet.morebeer.com/files/W501.pdf
It would be unusual to have a white wine with that pH and that high of TA. Your tongue should be an excellent 2nd (or 3rd) opinion on the TA. That TA should be fairly tart on the tongue.

You can always let it finish and do a bench test(s) at some point and add more tartaric and then again let your tastebuds guide you along the way.

With the TA test kit I always use. 100ml distilled, 6 drops phenolphthalein, 5ml must then 0.1 NaOH solution. I tested my Cab Sauv last week and Zin a week earlier and the tests were accurate, so the solution should be good. I am scratching my head on TA this high for grapes this late. I expected something in the 6.x range for SB this late.

The only difference, is that I am used to reds, so the solution turns blue/grey, where with whites it goes pink. The endpoint (pink) was at 6.0ml for the first test and 5.9ml for the second. Is there anything different for whites?

 

[Denden5136]

While phenolphthalein will give you a decent number I would test again using your pH meter to detect endpoint more accurately (ph=8.2)

It would be unusual to have a white wine with that pH and that high of TA. Your tongue should be an excellent 2nd (or 3rd) opinion on the TA. That TA should be fairly tart on the tongue.

You can always let it finish and do a bench test(s) at some point and add more tartaric and then again let your tastebuds guide you along the way.

ibglowin,

Well said on letting the tongue be the second opinion - it is not overly acidic and in fact tastes/smells very well balanced. I did another test and it came out at 7.8. I think I am used to the more dramatic color changes at endpoint with reds. This has been a great learning experience (so far) for a white wine newbie!

Separately, another new observation with whites, without the skins there is nothing to keep the foam down when the primary really takes off - amazing to see - like bubble bath as a kid

I will raise the acid just enough to get the pH under 4 and re-test when it goes into the stainless at the end of the primary.

 

[CDrew]

The reason the end point is 8.2, is because that is the (traditional) phenolphthalein end point pH. And Phenolphthalein preceeded pH meters by decades hence the reliance on the pH at the color change point. Since there is very little NaOH amount difference between say 7.0 and 8.2 (since you are well out of the buffered zone by then), you could still use that as an endpoint. It's just everyone standardized their process using Phenolphthalein as the indicator, that we still use pH 8.2 as the indicator today. I think it's pretty cool actually.

 

[Denden5136]

Very cool indeed - I will use my pH meter for the test at the end of the primary. Then I can check it vs. the color change.

 

[Snafflebit]

check your bottle of sodium hydroxide. Once I had a bottle that was 0.2 N and I did not realize it. That made the acid measurements double. Never mind that would make the acid measurement half

I took a class taught by a very experienced winemaker this summer and he says he never even measures TA. He goes strictly by taste unless the grapes have a serious problem that needs to be fixed, like rot.

 

[BarrelMonkey]

I think I've posted this before but the Vinmetrica website has a useful guide to pH, TA and associated adjustments:

Managing pH and TA in wine – Vinmetrica – Sulfite (SO2), Malic, Alcohol & pH/TA tests for Wine, Beer & Kombucha.

Caveat - I am a white wine newbie myself (as a winemaker, though I help make white wines at the winery where I work). Even if the juice tastes nice now, I think it risks getting 'flabby' if it stays that high (though it will drop a bit during fermentation). Add some tartaric acid, maybe? Perhap as part of a water additrion since brix is high too? The earlier the better - if it only just stared fermenting it should be a good time to do it.

 

[Denden5136]

BarrelMonkey,
Similar situation for me - I help make whites at a winery, but my first time at home. Home has its own challenges - no glycol chillers and no super large primary fermentation tanks.
I have made one addition of tartaric acid and will re-test this evening. I moved the wine (down to 4 Brix as of yesterday, so will call it wine) to a Speidel stainless tank last night. The aromas are great and I don't want to lose them. Your comment on flabbiness is well taken. I will make sure the TA is where it should be.

I am already thinking about how I will do whites better next year and I haven't fully completed the primary of this yet. This hobby, no, "lifelong quest" is addicting even after more than 10 years!

 

[BarrelMonkey]

Similar situation for me - I help make whites at a winery, but my first time at home. Home has its own challenges - no glycol chillers and no super large primary fermentation tanks.

Yeah, wouldn't a glycol chiller be nice? I think I'd like to try making a couple of homemade white wines (and set up a more permanent home 'winery') before making that sort of investment. I'm currently fermenting in stainless steel kegs and although they're in my cool cellar they were 70 and 75 °F this morning. Wish they were 10° cooler...

 

[Denden5136]

So an update on the Sauvignon Blanc. I racked into stainless and reserved a small test sample. I work from home, and left the sample to sit for 3 hours while I had a conference call.

I test and now the pH is 3.77 and using the pH meter watching for 8.2 rather than just color change, it tests at 6.6 TA! This matches what my nose and tongue are telling me. Could it be that active fermentation itself has an impact that can skew test results? I have never read this or experienced this before. Anyone else with a similar experience?

 

[ibglowin]

Yes, active fermentation will skew your pH meter as CO2 produced in fermentation and water can form Carbonic Acid in solution.

 

[Snafflebit]

I wonder if 3 hours is enough time for the carbon dioxide to bubble out completely. Carbonic acid will lower the pH. If you add any more acid, I would do it very gradually if you can and test.

@ibglowin Jinx, owe me a Coke (speaking of carbonic acid...)