How To Understand ph, and Take A Reading

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djrockinsteve

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How To Understand ph, and Take A Reading

The ph of your must is one of the biggest factors that can affect the outcome of your wine. Ph affects the flavor, aroma, color, stability and being able to survive the test of time in a bottle to say the least.

Wine ph is a logarithmic scale used by chemists to describe the number of hydrogen ions present in a solution. The scale is an “upside down” scale meaning the lower the number, the more ions that are in your wine. A reading of “0” represents the most acidic while “14” being the most basic. A ph of “7” being neutral. We accept water as being neutral.

The scale is logarithmic meaning that a reading of 3.0 contains ten times more ions than 4.0 The most accurate way to get a ph reading is with a meter, however in a pinch, litmus strips can be used as a rough gauge by dipping one into your must for a brief second then removing to compare to a color chart. Recommended ph ranges for wines are 3.4 to 3.65 for reds and 3.1 to 3.45 for whites and 3.5 to 3.6 for fruits.

Your ph value represents acids present in the wine and their strength. Wine ph is dependent upon the total amount of acids present, a ratio of malic acid to tartaric acid, plus the total amount of potassium present. Wine acids produce hydrogen ions while the ph is a measure of the number of hydrogen ions present in the must/wine.

The ph will be lower when titratable acid is higher but high titratable acid does not always produce low ph values. Potassium present in a must or wine can alter a wines ph. Malic acid is weaker than tartaric acid which can result in a wine high in malic acid have both a high total acid (TA) and a high ph level. When the total acid content is fixed, ph depends upon the relative amount of tartaric and malic acids present. This is why 2 wines may have the same ph, yet have different acid percentages.

Advantages of a low ph in your wine.
In the range of 3 to 4 ph there is a very little influence in the taste of the wine from the ph value.
The chemical and stability of wine at this range is greatly improved.
Commercial yeasts and their fermentations are not affected by normal ranges of the ph. The intensity of the color of your wine is improved.
Fining ingredients work at their best in these ranges at clearing proteins and sediment from the wine.
Less Sulfur Dioxide is needed to protect the wine.
Bacterial growth is greatly hindered in wines at low ph values.

Many of the problems associated with wine making are a result at least in part due to a high ph. This is why it is important to know your wines ph.

There are many different types of instruments you may purchase to monitor your wines ph. The one shown below is from Hanna Instruments model # 98128. It is water proof, adjusts for temperature (either F or C), calibrates easily and retails for around $120.00 You will also need buffer solutions “4.01 and 7.01” with this unit. With basic care it will last a long time.

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Calibration of the tool is recommended monthly or more if used often. To calibrate this model, turn on. Then depress the “on” button and hold until the letters “CAL’ appear. Release the button, then “7.01” will appear. Insert the two electrodes fully into buffer solution 7.01 and wait while the unit calibrates to a 7.01 value. Once accepted the “4.01” value will appear. Immediately insert the unit into the “4.01” buffer solution. (If not done within 12 seconds a “WRNG” message will appear. Once the “4.01” is calibrated “OK 2” will appear and you are finished calibrating the meter. The meter will move to a normal reading mode.



After calibrating the instrument rinse off the two electrodes (one for ph one for temperature) with water and insert the probes into a sample of your must/wine. The LED reading will change a few times then after a few seconds stop, giving you your ph reading adjusting for the current temperature. If your must/wine is in the recommended range you need do nothing at all. If your must/wine needs adjustment, make the appropriate changes and test again (see below).

When finished, rinse off the electrodes and replace the protective cap filled with 4.01 solution. Always keep the electrodes wet. Should they dry out refer to the directions on how to “revive” them. Never store in distilled or tap water.

To adjust a must ph can be done via a number of ways. The addition of 1 level teaspoon per gallon of tartaric acid for grapes or acid blend for fruits will raise the acid level by approx. .15% (note the .) It is best to make changes prior to the addition of yeast as to avoid shocking them. Adjustments can also be made post fermentation. Blending with a must/wine of higher ph is an alternative method but not always feasible.

To lower acid (raise ph) you can add water. This may or may not be desirable. Sometimes juices can be so concentrated that the addition of water will lower the acid along with the specific gravity.

The addition of Calcium Carbonate to your must (preferably not wine) of no more than 0.3 to 0.4% as your flavor of the final product will be affected. One teaspoon (3.4 grams) of Calcium Carbonate per gallon will reduce acidity by approximately 0.1%

Potassium Bicarbonate de-acidifies a wine by neutralizing acid. Do not try to lower the acid by more than 0.03% and don’t use this if your ph is above 3.5 By using 1 teaspoon (3.4 grams) per gallon will lower acidity (raise ph) by approximately 0.1% Use a large container as excessive amounts of foaming will occur.

Cold stabilization for at least 3 weeks will also help to drop out some acid in your wine. Add 2 to 5 grams of Potassium Bitartrate (cream of tartar) per gallon of wine and stir daily to redistribute the crystals to expedite the dropping out of tartaric acid crystals (white diamonds). Rack afterwards before wine warms up.

Generally if you purchase/get juice from a professional winery your juice will most likely (but not guaranteed) to be sulfited and ph balanced. The amount and types of acid it contains will depend upon the reigon grown, amount of sunlight, temperatures, rain, soil when picked and countless other things.

Getting fruit from other sources is where you need to pay closer attention to your fruits sugar, ph and acid levels. It is best to make your changes prior to fermentation as proper levels will assist the fermentation process. Finally adjust as per your taste. The ranges above are basic standards but this doesn’t mean you can’t slightly adjust them to your own personal liking.
 
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Julie

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So what happens if you do get the "WRNG" message?
 

Julie

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Steve!!!! :ftROFLMAO what kind of answer is that????? You always have the correct answer when I ask. Geez, ok I'm going to check my directions.
 

djrockinsteve

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Take the thing to Dans and when he locks you down in the wine cellar swap his for yours. Problem solved.
 

LoneStarLori

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Thanks for this post Steve. I have just started thinking about what PH should be and all the things I don't know about it. This helps give me the big picture.
 

corinth

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djrockinsteve:

Your information is way over my head but I would rather have too much info than not enough. Excellant
 

djrockinsteve

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Hey it's way over "our" heads.

Don't over think it. If you are making wine from professional sold juice you usually won't have a problem. It's when you pick fruit yourself or create something odd like candy cane wine you need to do some thinking.

If you can take ph and or acid readings from good juices and wines. This will help you compare.

I don't record much anymore my commercial juices other than gravity.

Ask if you need to understand something. That's why we are here.
 

djrockinsteve

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You are welcome. The important thing to remember is not to get so deeply involved with trying to totally understand such a thing that you turn a fun hobby into something overwhelming.

If you start with quality juice you shouldn't have difficulties. It will already be ph and acid balanced. Fruit in the eastern US tends to be more acidic than the west coast. Taste the differences and enjoy rather than attempt to match them.

Creating your own juice not fully ripened fruit will be more acidic so either wait until it peaks or blend with something to help lower the acidity. No wine that we as hobbiests make is perfect. That's okay.

Be aware of your juices ph, follow how it changes over time. Enjoy.

There are other tutorials by a few of us that help tie ph into the whole scheme of things. FYI
 

Norske

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Potassium Bicarbonate de-acidifies a wine by neutralizing acid. Do not try to lower the acid by more than 0.03% and don’t use this if your ph is above 3.5 By using 1 teaspoon (3.4 grams) per gallon will lower acidity (raise ph) by approximately 0.1% Use a large container as excessive amounts of foaming will occur.

Can you explain why you recommend not adding more than .03%? Some of our fruit wines, such as lingonberry and red currant start out pH of 2.8-3.0 and we need to add quite a bit of Pot bicarb to adjust the pH pre-ferment.
 

razelegendz

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Hey, I know this is an old thread, but I just wanted to point out there is such thing as a negative PH, meaning 0 isn't the most acidic.
 

JONJON

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Hi @djrockinsteve

I'm pretty new to this but my Shiraz is 3.95 pH. I've added yeast 2 days ago. Am I better waiting until I press before I add acid? Cheers Jon
 

Rice_Guy

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* ,@JONJON this is an old thread, you may not get Steve. On another thread you are today fermenting Australian grapes.

* acid? In food processes acid is used as a fence which keeps microbial infection at bay. Because of this I would have adjusted the acid to my target before conducting a room temperature fermentation. You have yeast doing their job which involves the release of CO2 which will lower the pH. As a guess it probably is 0.2 units lower than the original must. The pH will rebound after fermentation and degassing.
Because a fermentation is in transition I would make some correction to get below 3.7 for red or 3.5 for white and country wines. I would expect that it moves some by the time the wine is six months old.
* effectiveness of metabisulphite? For storage after the wine has stopped degassing we add meta. Metabisulphite is more effective at lower pH so I would want the pH targets above, ,, for achieving a few years of shelf life.
* flavor? The pH is not as important as the total number of acid molecules in the glass/ your mouth (called TA). On a short shelf life wine you could thumb your nose at the pH targets. The quantity of acid and tannin in wine needs to be in balance with the sweet flavor notes. This may result in bad/ high pH goals. ? your TA ? typical target is 0.5 to 0.7% as tartaric acid.
* the AWRI is a fantastic resource, Australia has some excellent wine makers.
 
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Johnd

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@JONJON , it's also important to recognize the difficulty in obtaining an accurate measurement of pH once fermentation has started. The presence of CO2 in your wine will give you an inaccurate reading, but there is a way to do it. Take a sufficiently sized sample of the must, including skins and pulp, an put it into a blender and puree the must. Strain the puree through a piece of cheesecloth, or paper towel, something to separate the liquid from the solids, heat the liquid up into the 80's and shake it vigorously to remove any remaining CO2, then you can take your measurement.
 

JONJON

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* ,@JONJON this is an old thread, you may not get Steve. On another thread you are today fermenting Australian grapes.

* acid? In food processes acid is used as a fence which keeps microbial infection at bay. Because of this I would have adjusted the acid to my target before conducting a room temperature fermentation. You have yeast doing their job which involves the release of CO2 which will lower the pH. As a guess it probably is 0.2 units lower than the original must. The pH will rebound after fermentation and degassing.
Because a fermentation is in transition I would make some correction to get below 3.7 for red or 3.5 for white and country wines. I would expect that it moves some by the time the wine is six months old.
* effectiveness of metabisulphite? For storage after the wine has stopped degassing we add meta. Metabisulphite is more effective at lower pH so I would want the pH targets above, ,, for achieving a few years of shelf life.
* flavor? The pH is not as important as the total number of acid molecules in the glass/ your mouth (called TA). On a short shelf life wine you could thumb your nose at the pH targets. The quantity of acid and tannin in wine needs to be in balance with the sweet flavor notes. This may result in bad/ high pH goals. ? your TA ? typical target is 0.5 to 0.7% as tartaric acid.
* the AWRI is a fantastic resource, Australia has some excellent wine makers.

Hi Rice_Guy,

Thanks so much for the information.

I didn't know about adjusting the wine before fermentation. I do now. The guy in the shop told me to add it after fermentation! Anyway we live and learn.

I tested the wine today with my pH meter and it read 3.98. The brix was at 8 and the SG was at 1.000. I bought a kilo of tartaric acid as it says i need 1g per litre to drop by 0.2 pH.
 

JONJON

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@JONJON , it's also important to recognize the difficulty in obtaining an accurate measurement of pH once fermentation has started. The presence of CO2 in your wine will give you an inaccurate reading, but there is a way to do it. Take a sufficiently sized sample of the must, including skins and pulp, an put it into a blender and puree the must. Strain the puree through a piece of cheesecloth, or paper towel, something to separate the liquid from the solids, heat the liquid up into the 80's and shake it vigorously to remove any remaining CO2, then you can take your measurement.

Thanks Johnd,

This is great thank you.
 

Rice_Guy

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Reading posts on here there seems to be a generic advice of go fairly slow, I also have been frustrated with guidelines unless I am taking a sample and titrating with the acid.

There is a chemistry called buffering involved. Water is transparent and the assorted solids are rubber bands stretching/ pulling the pH back to the starting point. The chemistry is dirty/ not predictable since every crop year/ harvest date has variation on acidic salts ratios. A flavorful dry year takes more acid and a wet year takes less. ,,, And if I step away from fruits a high temperature dried rice/ coffee will be different than a low temperature process.
today with my pH meter and it read 3.98. I bought a kilo of tartaric acid as it says i need 1g per litre to drop by 0.2 pH.
All in all start today, and stop at a high point expecting that there will be pH drift. Recheck in a few hours and decide if another correction is needed.
 
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