Please comment on my crush numbers TA pH

I would approach this the other way around. Add tartaric acid to bring pH into the 3.5 range then check the TA. pH is much more important from a microbial stability standpoint, than TA. Excess tartaric acid can be dropped out when cold stabilizing. The potential problems of a high pH environment are less easily remedied.

I would not skip the ML on your Zin, again, more for stability than style. Consider lysozyme if you decide not to ML your Chard.

RD

I have no idea how much Acid to add to lower pH?

RD wrote:

It's not easily calculated as pH depends on the buffering capacity of the juice among other factors. I simply want to point out that TA is a less important bogey than pH. Add your tartaric acid incrementally, monitoring pH rather than TA. You may (or may not) need to exceed your desired TA value of 0.7%, in order to bring the pH down to a safer level - that's ok it can be dealt with later.

RD

I think I am doing some math wrong. I need to figure it out. I added 40 grams of acid which should have gotten me to .7 g/l But it only took me from .46 g/l to .6 g/l So I added the same amount again... and did not check it.

I added acid until I was about pH 3.65 or so. This was twice my calculation to go from .46 to .7

I am going to let it sit over night and recheck the acid and pH

RD wrote:

I guess I should also add..

I did taste the must as I was going, it does taste much better now.

homebrewdude wrote:

Some comments -

I agree with RD up to a point. pH is more important from a microbial stability point of view. The one caveat I would make is that TA is important for the perceived quality of the wine, especially the chardonnay. I would recommend doing what RD suggested - increme3ntal additions of acid and continue to check both pH and TA and taste.

The other comment I'd make is that those are kinda weird numbers. Low acid, but also low sugar. With those acid readings, I would have expected a much higher sugar reading. Are you confident in your testing equipment and procedures?

I am using a ATC refractometer I calibrated it with distilled water.

I measured juice direct from berries and after the crush.

I am using a calibrated Hanna Phep5 meter. I am using Hanna calibration solution. New probe a week ago.

I am going to take a SG reading with my hydrometer today, to check the sugar again.

The grapes are from California shipped to the midwest.

AxisOfBeagles wrote:

My Chardonnay sat over night It is much clearer now, I added yeast last night but there is no activity yet.

I re-calibrated everything Brix 24 SG 1.110 pH 4.07 TA .35 g/l

THis is how I worked through my TA

15ml of juice 15ml of distilled water 3 drops of indicator

The was in a beaker placed on a stir plate with pH meter

I added 3.5ml of NaOH then it hit pH 8.22

Based on my math this would be .35 g/l

these new readings are after I added 20 grams of acid last night... The wine tastes sweet, I still think it is low on acid.

Now I am confused...

homebrewdude wrote:

I added 70grams of acid

Now

pH 3.60 TA .65 g/l

10 more grams will bring the TA to .7 g/l

Then I will recheck pH, which should drop more.

I was planning on ML this one, but I guess not now... I think I will add some oak to the primary

homebrewdude wrote:

I went ahead and added acid to get my TA to .75

My final pH is 3.49

homebrewdude wrote:

On reds from grapes I usually try to get the pH to 3.6 and then stop. I do use tartaric only for that type of addition. I had to add a lot this year too. My rule of thumb is 4g/gal to increase TA by 1g/l. If you want to change the pH by 0.1 4g/gal (US) is about right. Bigger swings than 0.1 PH get a little crazy to calculate. It's easier to add some acid and just remeasure rather that try to calculate. It's a logarithmic measurement so you will drive yourself crazy trying to calculate it out since we think in linear values. Your numbers seemed a little odd to me too but calibrated is calibrated so go with that.

Joe

What number seems odd?

Your numbers seemed

I don't usually do ML on grapes like this, your initial acid numbers kind of point to overripe but your sugar does not. Overripe grapes don't have a lot of malic acid as I understand it. People that do ML routinely usually want to get the target pH a little lower, like

3.3.

Joe

Malolactic conversion will typically reduce acidity. Malic acid, a dicarboxylic acid, gets decarboxylated to form lactic acid, a monocarboxylic acid, and CO2(g). This will likely raise the pH (though not dramically in my hands), not lower it.

Malate, like residual sugar, is a potential energy source for bacteria. One goal of ML'ing is to remove that potential energy source. Many species of lactic acid bacteria may be present in a wine. Some are benign, some are considered spoilage bacteria. Any of them may eventually utilize the malate under the right conditions (temp above 65F, pH above 3.2, low sulfite levels, sufficient nutrients, etc.). It can and does occur after bottling, which can be heartbreaking after all your effort, leaving you with spoiled wine. Encouraging the ML conversion by innoculating with a benign strain (O. oenos) helps me sleep a bit better at night.

To ML or not is entirely up to you. Be sure to maintain adequate SO2 levels for your wine's pH if you choose not to ML.

RD

This is an excellent thread!! I'd like to skew off on a related but tangent subject if you guys will humor me for a moment...

I recently attended a seminar in which one of the topics was winemaking techniques for Cynthiana/Norton grapes. These grapes are typically very high in acid (>1.2) and often high pH (>3.5). The presenter was advocating the addition of tartaric acid to drop the pH down to 3.5 prior to fermentation and let the acid fall where it may. Then cold stabilize after fermentation to precipitate out tartrates and get the acidity back down. Here's my rub(s):

1. Some resources claim that ML is inhibited in musts with acidity greater than 1.0. By adding tartaric, the must acidity will exceed

1.2! If these resources are correct, wouldn't the odds of ML inception and completion be slim? They say ML is particularly important in wine musts high in malic acid like Cynthiana. What gives?

1. If resources mentioned in #1 above are right, wouldn't acidity in a pre-fermented wine must be more important than pH to ensure successful ML? I know pH is very important for long-term stability of wine after bottling but does it really matter during vinification? Can't wine stability issues from high pH levels be dealt with after fermentation simply by adding a little more SO2 prior to bottling?

2. Once the cold stabilization precipitates out the tartaric acid, wouldn't the must acidity and consequently pH end up right about where it started before the tartaric addition? If yes, what was the point?

Please enlighted me. I sense I've been missing something crucial in my winemaking process!

Concerned, Charles Erwin

I've included my understanding of your points within your message.

I hope I'm not being too technical to be understood.

Gene

Charles E wrote:

I've not heard before about acidity greater than 1.0 inhibits MLF. One commercial winery I know of occasionally adds 1 gm/liter tartaric acid without inhibiting MLF. Can you provide a reference that I might read in which this claim is made?

MLF is inhibited when the pH is lower than 3.1. Adjusting pH downward to 3.5 is not enough to inhibit ML fermenation.

MLF is inhibited by small additions of fumaric acid, but we don't adjust pH in our grape must with fumaric acid.

The yeast's ability for vinification of grapes is not noticeably affected even at high grape pH. High grape pH does allow some kinds of bacteria to grow during vinification which can cause off-flavors, so you have pay more attention to sanitation practices when fermenting high pH grapes.

At pH greater than 3.8, the chemical form of sulfur which protects the wine (called molecular sulfur) is in such low concentration that oxidation and bacterial spoilage of the wine are real risks, unless so much SO2 is added that you begin to taste it in the wine.

Oxidation and bacterial spoilage is more a problem for white wines than red wines because the polyphenol compounds in the red wines do offer some protection.

Potassium ions in the grapes are largely responsible for the high pH. When you lower pH using tartaric acid additions, the tartaric acid reacts with potassium ions to form potassium bitartrate. Cold stabilization precipitates (forms crystals) of potassium bitartrate which do not redissolve in the wine at normal wine storage temperatures. With the fraction of potassium ions gone from the wine, the pH will stay lower than where it started.

Other chemical reactions in the wine can raise the pH again, but usually less than the amount we have lowered it by removing the potassium ions.

Charles, I've not heard anything about high TA being an issue with ML either but most of the books I read don't talk a lot about hybrid winemaking. I have a few that do so I'll look. I'm hoping to make a few hybrids this year and it's always good to brush up. I'm sure the people at Cornell have thoughts on this and most of their work is not to hard to find on the internet. An email to them always gets answered also.

Did the mention using Lalvin 71B? It likes malic acid and often consumes a bit of it during fermentation.

RD, I probably could have phrased that previous post better; I was not saying ML will lower pH. I was saying shooting for a pH of 3.5 might not add enough tartaric to bring the potassium out. It's my understanding that high TA and high pH usually indicates a high potassium level. Genes post was much clearer on that. Tom S always shoots for 3.3 as I remember it.

Joe

Hi Joe, Thanks for the clarification. I see what you meant now about high TA/ high pH/ and K+.

RD