PH Adjustment--when

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johnc3

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We have about 160 Zinfandel vines near Calistoga California.

Harvested today. Field measurements were 26.2 Brix and PH 3.2, on the low but acceptable side.

After crush measurements were 25 Brix and PH of 3.15.

I am considering adjusting the acidity downwards as I've had past vintages ruined by excessive acidity.

Should the must be adjusted now, before introducing yeast? Or better to ferment and adjust after pressing, or waiting even longer until after malolactic fermentation and see where things sit then?

Appreciate any insights on this.
 

NorCal

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Wow, we have the opposite problem here in the Sierra Foothills; at 26 brix you will most likely be seeing a 3.8-3.9 pH wine. I’ve found that being aggressive on the adjustments pre-ferment and then living with the wine has served me the best. I’ve seen too many wines ruined by trying to hit a pH or TA number post ferment.
 

Rice_Guy

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Your pH will move during fermentation so I am not surprised to see a bounce of 0.1 unit today. You still have tools to move the acid as chilling and malolactic fermentation. Next as far as fermentation, a low pH is safer.
From a midwest perspective I got a white juice bucket from the local winery yesterday with a pH of 3.04 (TA 1.8%), I expect that it will change some as the solids drop out, and the yeast/ CO2 will push the pH to about 2.8 and still make a dry fermentation.
 

Johnd

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Personally, I'd attempt to raise the pH a couple of points prior to AF and MLF, values as low as the ones you have can cause difficulty in both AF and MLF. As @NorCal said, you need to be a little aggressive in this preferment adjustment, as the pH will typically trend back to its previous level. I believe that this occurs because when we adjust the pH of the must, we are only monitoring the affect of the adjustment upon the juice that has been freed from the grapes, and there's still a lot left to be liberated as AF progresses. Your adjustment will have no effect upon the juice still locked inside the grapes. As this low pH juice is released during AF, it'll pull your pH back down a bit. If I were the winemaker, I'd be shooting for somewhere around 3.6 as a preferment reading, knowing that it will likely fall back, but if it sticks, 3.6 is still a great place to be.......

Make sure that you are 100% confident in your pH reading!!!!
 

takenbywine

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i consider being a new wine maker but someone tell me about the ph acidity? what am i looking at in the taste such as muscadine and fruit wines. Last year my wine was very sour to bitter. Is that a high or low acid taste? When a recipe calls for malic acid, tartaric acid in different amounts, how do i balance this with acid blend? I do appreciate all the suggestions on the site.
 

johnc3

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Thanks for the thoughts. I've never actually adjusted the PH of must before AF, only afterwards when the wine was finished. Results were not good, 10 gallons of wine down the drain.

I plan to try potassium bicarbonate. Does anyone have a good link for a spreadsheet to do some calculations? Stressful as time is passing on the must at this point.
 

Rice_Guy

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pH is a measure of intensity and sort of like feeling the wind with your hand out the car window, total acidity is like how big is something that went splat on your hand. Everything relates back to what your taste buds detect, ex
* whites are usually pH 3.2 to 3.5 with a TA of .5 to 0.7%
* reds are usually pH 3.5 to 3.7 with a similar TA BUT tannin in the red adds impact (wind) on the tastebuds so it feels balanced
* a beverage as Pepsi is pH 2.5 but the TA (how big) is only 0.2% so the flavor feels balanced, ,,, and the sweetness is high as 1.045 gravity
* I do a style with lots of fruit/ no water in country wines so I build a ph of 3.2 with a high TA as 1.2% but like soda folks seek a balance so I back sweeten to 1.015

The key is balance, if one reading is high the others have to move to compensate so the sensation on the tongue is similar.
Next lesson, ,,, some things like meta ionization to SO2 are not taste related so the chemistry is only related to the pH and not the quantity of acid. ,,, and this food system becomes more complicated.
i consider being a new wine maker but someone tell me about the ph acidity? what am i looking at in the taste such as muscadine and fruit wines. Last year my wine was very sour to bitter. Is that a high or low acid taste? When a recipe calls for malic acid, tartaric acid in different amounts, how do i balance this with acid blend? I do appreciate all the suggestions on the site.
 

NorCal

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Thanks for the thoughts. I've never actually adjusted the PH of must before AF, only afterwards when the wine was finished. Results were not good, 10 gallons of wine down the drain.

I plan to try potassium bicarbonate. Does anyone have a good link for a spreadsheet to do some calculations? Stressful as time is passing on the must at this point.
Here is a link to a calculator, but I have found that the actual results can vary greatly. I believe this is tied to the buffering capacity of the wine, which will vary wine to wine. I always add very little at a time and measure. You can also hit a tipping point; your additions each time will not result in the same change in pH. So go slow, do a little at a time and while time consuming, it avoids making a mistake.
 

wood1954

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Do your calculations and add half of what you calculate, wait a day and remeasure, repeat until close. Being impatient I’ve learned to slow down and not ruin my wine. As NorCal says every wine will react differently
 

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