Well that's interesting but when I looked at the manual, it does indeed say that for all USDA tested recipes.

Speaking only of my own comfort level, I would not be concerned using the lower acidity vinegar for a 100% vinegar recipe but since it's on the lower end of the acceptable range, with, say, a 50:50 ratio of vinegar to water, I would use the stronger vinegar.

I would guess that 5% figure is a simplification and a way to avoid the problem of people who are inclined to push boundaries. That way if someone does use rice wine vinegar there is that additional latitude, even if they're not aware of the fact.

Carol

Most, not all, commercially sold vinegars are rated in whole percentages, thus the 5% recommendation and IMO it should be followed whenever possible. Those labeled 4% would be bottom borderline and perhaps suspicious, depending on the brand, so not worth the risk for me.

So as Carol said, if it is a straight vinegar brine I'd be comfortable with it but I wouldn't use it in a diluted brine recipe.

You know you can contact Dr. Elizabeth Andress at NCHFP directly by email if you want to clarify the guideline even more.

Dave

Thanks Carol and Dave. The general pickling excerpt reads "look for vinegar that contains 4-6% acetic acid or 40-60 grain acetic acid," but I don't see any tested recipes that specify anything but 5% so I'm not sure why they included the lower and higher values. Good idea about emailing Andress. I teach a lot of pickling classes and want to make sure I'm giving them the right info.
Anyway, I know Linda Ziedrich has that conversion formula for rice vinegar.... Hmmm. Ok, thanks again :)

You probably have it since you mentioned Linda Z but here it is from her blog last summer:

"â Multiply the volume of 5-percent vinegar in the original recipe by 1.16 (because 5.0 divided by 4.3 equals 1.1627906). The result is the volume of 4.3-percent vinegar in your revised recipe.

â Subtract the volume of 5-percent vinegar in the original recipe from the volume of 4.3-percent vinegar in your revised recipe. Reduce the volume of water in the revised recipe by this amount."

If a recipe' calls for 50% water and 50% vinegar with 5% acidity, then the new mixture has 2.5% acetic acid.(slightly less)
But let us say that you have a vinegar with 4.5% acetic acid. At what proportion you have to mix it with water to get a final mixture with 2.5% acetic acid ?

The answer is: you mix 55% vinegar to 45% water (roughly).
The final mixture should have about 2.5% acetic acid.

.............................
(4.5)/(100 +x) = 0.025
x= 80
added water to vinegar ratio = (80)/(100+80) = 0.444

Note: this is not mathematically exact. but close enough

This post was edited by seysonn on Fri, Sep 27, 13 at 23:26