Obviously, using approved recipes takes the guesswork out of it, but sometimes folks like to understand the "Why" factor, too.

This list is by no means comprehensive, and is compiled from a number of different sources (the USDA, various extension services, some trusted canning books). Also, it very much depends on the variety of fruit, so that is one reason for the wide range of values on certain fruits, like apricots. Some of the information has not been updated recently, but it should be a good guide.

High Acid=Low pH Number

Lemon Juice 2.0 - 2.6
Lime Juice 2.0 - 2.4
Lemons 2.0 - 2.4
Limes 2.0 - 2.8
Cranberries 2.3 - 2.7
Vinegar 2.4 - 3.4
Gooseberries 2.8 - 3.1
Grapes 2.8 - 3.8
Plums 2.8 - 4.5
Currants, Red 2.9
Pomegranates 2.93 - 3.10
Grapefruit 3.00 - 3.75
Strawberries 3.00 - 3.90
Rhubarb 3.10 - 3.40
Blueberries 3.12 - 3.33
Quince 3.12 - 3.40
Pineapple 3.20 - 4.00
Cherries 3.20 - 4.10
Raspberries 3.22 - 3.95
Apples 3.30 - 4.00
Table Wine 3.30 - 3.70
Apricots 3.30 - 4.80
Peaches 3.30 - 4.05
Tangerine 3.32 - 4.48
Mangoes 3.40 - 4.63
Pears 3.50 - 4.60
Elderberries 3.60 - 3.80
Oranges 3.69 - 4.34
Tomatillos 3.83
Blackberries 3.85 - 4.50
Nectarines 3.92 - 4.18
<---Cutoff for BWB Processing is pH of 4.6--->
<---Anything below this line (a pH value of more than 4.6) must be acidified (with lemon or lime juice, citric acid, vinegar, etc.) for safe BWB Processing--->
Dates 4.14 - 4.88
Tomatoes 4.30 - 4.90
Bananas 4.5 - 5.2
Peppers 4.65 - 5.45
Asian Pears 4.7
Figs 5.05 - 5.98
Watermelon 5.18 - 5.60
Onions 5.30 - 5.85
Melons 5.78 - 6.67

For reference:
Pure Water 7.00

Carol