"Low-acid" tomatoes - Is there such a thing?

[korney19]

Aunt Gertie's Gold: N/A
Beefsteak: Brix 4.98, pH 4.50
Black From Tula: Brix 5.38, pH 4.41
Brandywine: Brix 4.95, pH 4.34
Cherokee Green: N/A
Cherokee Purple: Brix 5.33, pH 4.48
Cosmonaut Volkov: N/A
Jaune Flammee: N/A
Kellogg's Breakfast: Brix 5.20, pH 4.38
Lime Green Salad: N/A

Black Cherry:
Bloody Butcher:
Galina's Yellow:
Japanese Black Trifele:
Riesentraube: Brix 7.15, pH 4.50
Sungold O.P.:

Brix is a measure of sugars. Suprising to many is that some high sugar/Brix varieties sometimes taste too mild or bland. I guess you'd have to weigh the Brix vs pH and decide.

The chart I had ranged from 3.98 pH to 4.76 pH. The higher the pH the less "acidic." Many of the paste types were at the higher end of the pH (less acidic) and Cherokee Purple was maybe a third of the way down the list, so it's less acidy than many of the others.

Also note that pH isn't a linear/proportionate scale. I believe it's exponential or something (help here please) whereas 1 point change is like 10x or 100x or ? Somebody please describe this better.

Mark

[korney19]

[korney19]

Maybe someone might want to sticky these...

[lakshmi]

Thanks for all the great info Mark! It gives me a clearer view of how tomato sweetness/acidity works.

Originally Posted by korney19

Also note that pH isn't a linear/proportionate scale. I believe it's exponential or something (help here please) whereas 1 point change is like 10x or 100x or ? Somebody please describe this better.

Mark

I just looked up the PH scale:

The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. The same holds true for pH values above 7, each of which is ten times more alkaline (another way to say basic) than the next lower whole value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8

For the more technical: pH = - log [H+] (where H is the concentartion of Hydrogen ions). When the concentration of H+ ions in a solution is 10^-14, the pH is 14. In pure water, the average concentration of H+ ions is 10^-7

Lakshmi

[korney19]

So we have enough varieties listed for an example to make say, Longkeeper almost 10x more acidic than something at the top? How does the fractions work? Would 0.5 difference = 5x more acidic?

[lakshmi]

I don't think so...it is exponential.

inv log 1 = 10
inv log 1.2 = 15.85
inv log 1.5 = 31.62
inv log 1.75 = 56.23
inv log 1.9 = 79.43
inv log 1.99 = 97.72
inv log 2 = 100

or
inv log 5 = 100000
inv log 4.5 = 31623
inv log log 4 =10000
inv log 3.5 = 3162

It seems to me that the difference is times the inverse log:
.5 difference -> inv log of .5 = 3.1622 so it is 3.1622 times more acidic or alkaline.

You can try this on your windows calculator by switching the view to scientific.

Lakshmi

[feldon30]

http://en.wikipedia.org/wiki/PH

The pH scale is a reverse logarithmic representation of relative hydrogen proton (H+) concentration.

A shift in pH from 2 to 3 represents a 10-fold decrease in H+ concentration, and a shift from 2 to 4 represents a one-hundred (10 × 10)-fold decrease in H+ concentration.