Measuring the pH of fresh tomato juice

[MrBig46]

I wonder if any of you here at Tomatojunction measured the pH of tomato juice. Does pH say anything about whether a tomato is sour or sweet, along with the measured Brix, of course? Every experience (even a link to an article on this issue) interests me.
Vladimír

[Shule]

Sourness often (not always) corresponds with the taste of acids that can lower pH. Different acids taste different. To me, citric acid, ascorbic acid, malic acid, oxalic acid, and acetic acid definitely taste sour. Malic acid tastes a lot like sour green apples. Leaves high in oxalic acid, such as sorrel, taste a lot like malic acid. Citric acid tastes like lemonade (and in my opinion, it adds somewhat of a sweet taste along with the super sour taste). Vitamin C tastes like vitamin C (just chew up a tablet to see). However, I don't notice too much sourness coming from lactic acid in lacto-fermented vegetables--but I taste a little sourness/tang in yogurt; I've never tasted pure lactic acid, or pure oxalic acid; many people notice a lot more sourness in lacto-fermented things than I do.

Tomatoes are known to have citric acid, vitamin C, probably malic acid, and probably other acids. I imagine they might have chlorine/chloride in them, too (it tastes like it to me, anyway, for some varieties, especially when fully ripe, such as Early Girl F1). Chlorine (in normal amounts in city water, anyhow) doesn't taste sour to me. It has more of a smell than a taste.

Supposedly, tomatoes can have over 10 different kinds of acids in them.

Mixing citric acid and ascorbic acid together in water tastes a bit like tomato acids to me.

Some people call things that I refer to as sour bitter. To me, bitter is like the flavor of cumin, chicory, Tylenol and magnesium chloride, while sour is things like vinegar, lemonade, and rhubarb. Grapefruit is both bitter and sour. I don't actually drink sour milk; so, I can't tell you if I think it tastes sour (but I use the sour there to describe how it's gone bad, rather than what it tastes like). Sour cream tastes mildly sour to me.

[MrBig46]

Of course, we all perceive sweetness and acidity a little differently. I have a problem with acetic acid. When it is a bit more, so even my eyes to react by tear. When cabbage is fermented, lactic acid is formed first, and later acetic acid is also formed there. I only let the cabbage ferment for about a week and then I stop the fermentation by sterilization. That's how I like it.
Why did I open this thread? In the first half of May, I will plant my tomatoes in the garden, so there will be room for more seedlings outside the window. I decided to sow about eighty other varieties of tomatoes at the weekend. For these tomatoes, I will monitor the DTM, the Brix value and I also want to measure the acidity by digitizing with a pH meter. For the tomatoes I have already grown, I want to get new, fresh seeds, for the new ones, taste them. Before I buy that digital pH meter, I need to get as much information as possible. The plan is big, I just don't know if I'll be able to fulfill it.
Vladimír

[mama_lor]

What you want is to measure titratable acidity. This is what they use in more scientific measurements along with brix, for an idea of how the tomato will taste. Usually tomatoes with both those values high score highest in taste panels.

[bower]

Yes a sweet tomato with some acidity will be described as "tangy" while a low sugar fruit with acidity will score as "sour".
I have to say the most acid tomato (and not sweet!) I have ever grown was Jagodka. The fruits I produced here in the cold, could substitute for lemons.

I'm very interested to hear your results Vladimir.
I do think that the best red tomatoes have a good score in the acidity as well as umami, regardless of brix.
We have come a long way (from our past ignorance maybe the first 40 years of my life!) in taste expectations of tomatoes. The variety of tastes available is way past the "typical red" parameters. I myself have gravitated towards sweeter tomatoes although I started with a preference for strong umami.
I have never measured any of these parameters with instruments, I will be interested to hear it!

[worth1]

I want all my tomatoes to have good texture over anything else.
They almost always end up tasting like mayonnaise or blue cheese anyway.

[MrBig46]

I have ordered and paid for this digital HP meter. He should be here this week. Tomorrow I will start sowing tomato varieties for testing. I selected about half of the determinants and the same number of indeterminates. Add to that the varieties I will normally grow, so there are a total of about 130 different tomatoes. I already feel that I will not be able to test them all. Technical data of the tester:
Specifications:
Measurement range: 0.00-14.00pH
Resolution: 0.01pH
Accuracy: ± 0.01pH
Operating temperature: 0 ℃ ~ 60 ℃
Calibration: automatic calibration of two points
Power supply: 2 * 1.5V batteries LR44 (not included)
Size: 155 * 30 * 14 mm
Determinante,Indeterminante
Beaverlodge Slicer,Amana Orange
Bezrassadnyi,Anna Rusian
Fireball,Black Pear
Forest Fire,Ciliega
Glacier,Dr Carolyn Pink
Kemerovets,Gigante Castilla
Krainy Sever,Cherokee Purple
Krokha,Joe´s Pink Oxheart
Lyana,KBX
Napoli,King Humbert
Nizhegorodskyi Kudyaliblik ,Moruno
Nordika,Negro Almeria
PSR-37,Neves Azorean Red
Puck,Palestinian,
RAF, Principe Borghese
Rhode Island Early,Rastrero
San Marzano nano,Rosa Sierra Aracena
Sanka,Yellow Brandywine
Severok,Roteňo Andalucia
Siberian Sprinter,San Pedro
Sibirskie Cherry,Tres Cantos
Silvery Fir Tree,Mam´s Heart
Tostyi Jack,Mexican Honey
Vspyshka,Gartenperle
Wayahead super,Solanum Pimpinelifolium
Yorkbec,Wes
Zolotse,Kimberly
Bower´s Birds Yellow
Dwarf Orange Grosse Liesse

[Harry Cabluck]

Good luck with your investigation. Will be great to hear what you learn.

[MrBig46]

The good news is, I got the digital pH tester today. Now I need advice on how to do this so that the measurement results of different tomatoes are comparable. So far, I have an idea that I am mixing a certain amount of tomato (for example 50 g). Then I would add 150 ml of boiling water and let it infuse for some time. I would strain the juice and measure Brix and pH. In my conditions, this procedure would be feasible on many tomatoes at once. Does anyone have a better idea or reservations about this procedure?
Today I planted the 56 varieties mentioned above.
Vladimír

[bower]

Hmmm I think adding boiling water would affect the pH. According to this research on the effect of heating on tomato juice pH, it would.
https://core.ac.uk/download/pdf/249336365.pdf
They say " Prepare samples of tomato juice. Tomatoes are selected which are full red, washed, sliced, blended, filtered, and taken liquids."
So the basic sample is not heated to prepare the juice.

[MissS]

I too think that boiling water would effect the PH. I also think that adding water would change the PH reading of the tomato's juice since the water itself has a PH. I would just use the juice of the tomato without adding anything. That is the only way to get a true reading.

[MrBig46]

Thanks for the advice. I'll probably buy some tomatoes at the store and try to make a sample of them. If I can do it, I'll measure the Brix with a refractometer.I will not measure pH yet, because I would have to calibrate the device for one measurement and then when I measure again. I only have one calibration powder pH 4.01 and one pH 6.86, I didn't get the pH 9.18 powder, they didn't have it. I will not need the pH 9.18 for tomatoes. It must be recalibrated after prolonged non-use.
Vladimír

[MrBig46]

282 / 5000
Výsledky překladu
Today I bought a liter of distilled water. Each of the two powders should be dissolved in 250 ml. I think that an acid of a certain concentration will be formed and it will not be a problem to store it in the glass for further calibration. So I would like to give the first measurement on tomatoes bought in the store now.
Vladimír

[MrBig46]

I sowed the tomato seeds on Tuesday and today, after six days, most of them germinated (marked *). I'll wait a few more days and sow again. Some varieties will be lost to me (I have no other seeds). I didn't expect much to germinate seeds from Carolyn's legacy, I just tried it (King Humbert, Joe's Pink Oxheart, Carolyn Pink ...). I want to try to germinate these with the help of GA 3, which I have already bought.
Vladimír

[mama_lor]

I found this meter for tomato, measures both brix and acidity (not pH, which as we know is not very useful). Probably expensive, might be equivalents from other companies.

https://www.atago.net/product/?l=en&f=p ... p#DCJ63626

[Whwoz]

[mention]MrBig46[/mention] , Bowerbirds yellow is a dwarf, typically upto 1 Meyer/40 inches high. Dwarf Orange Grosse Losses, which I am now referring to as Bowerbirds Orange due to significant differences between it and OGL . BO only made it to 600 mm /2 feet high last season, from the same lot of seeds that I sent you.

[MrBig46]

I found this meter for tomato, measures both brix and acidity (not pH, which as we know is not very useful). Probably expensive, might be equivalents from other companies.

https://www.atago.net/product/?l=en&f=p ... p#DCJ63626

It is not true (not pH, which as we know is not very useful). Even the device you recommend does not measure anything other than PH and then converts the result to citric acid. For my monitoring and piercing the tomatoes, pH is enough. As for the Brix sweetness, I would also like a digital, more accurate measurement, but I have a refractometer and I have to settle for it. The biggest problem of my measurement will not be the measuring instruments used, but maintaining the evenness of the measurement (especially measuring really ripe tomatoes). I do not know a relevant method of determining exactly when a tomato is really ripe for consumption and not immature or overripe.
Vladimír

[MrBig46]

@MrBig46 , Bowerbirds yellow is a dwarf, typically upto 1 Meyer/40 inches high. Dwarf Orange Grosse Losses, which I am now referring to as Bowerbirds Orange due to significant differences between it and OGL . BO only made it to 600 mm /2 feet high last season, from the same lot of seeds that I sent you.

Thanks to Whwoz for the information. Among the tomatoes that I will grow for these purposes are bush tomatoes and also indeterminate tall tomatoes. I'll cut the tall tomatoes behind the second inflorescence to fit me in the tunnel. That should be enough for tasting and other testing. Actually, these are not my main tomatoes that I will grow this year. I have sixty other indeterminate varieties, including Orange Grosse Liesse from you.I hope that even with some of them I will be able to perform measurements and other things as in this project.
Vladimír

[mama_lor]

I found this meter for tomato, measures both brix and acidity (not pH, which as we know is not very useful). Probably expensive, might be equivalents from other companies.

https://www.atago.net/product/?l=en&f=p ... p#DCJ63626

It is not true (not pH, which as we know is not very useful). Even the device you recommend does not measure anything other than PH and then converts the result to citric acid. For my monitoring and piercing the tomatoes, pH is enough.

Unfortunately, it does seem like it only measures pH, I thought it had something more fancy, for that high price. You are right, for a quick test pH is enough, but it is not the full truth of how acidic it will taste: https://www.sciencedirect.com/science/a ... 3245029084

I do have a cheap pH meter, I will out of curiosity measure pH when I find a particularly sour tomato that makes your lips hurt and compare to some of those I find bland. I wonder how much of a pH difference makes a difference in taste.

[Whwoz]

@MrBig46 , Bowerbirds yellow is a dwarf, typically upto 1 Meyer/40 inches high. Dwarf Orange Grosse Losses, which I am now referring to as Bowerbirds Orange due to significant differences between it and OGL . BO only made it to 600 mm /2 feet high last season, from the same lot of seeds that I sent you.

Thanks to Whwoz for the information. Among the tomatoes that I will grow for these purposes are bush tomatoes and also indeterminate tall tomatoes. I'll cut the tall tomatoes behind the second inflorescence to fit me in the tunnel. That should be enough for tasting and other testing. Actually, these are not my main tomatoes that I will grow this year. I have sixty other indeterminate varieties, including Orange Grosse Liesse from you.I hope that even with some of them I will be able to perform measurements and other things as in this project.
Vladimír

Mr Big, not sure how tall the Orange Grosse Losses will grow. Seed would be what I collected from a purchased plant that was fairly rugose looking early on but as it grew, became more regular looking in leaf shape. It would be this batch of seeds from which the BO was grown out. Fruit size was typical slicer sized out here, roughly 120 to 150 grams. BO produce fruit upto 250 grams early in the season, with latter fruit being smaller, down to golf ball size by end of a poor season.