Micro Essential Lab MF-1604 Hydrion Microfine Short Range pH Test Paper Dispenser, 2.9 - 5.2 pH, Double Roll

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Note: These reviews seem to be for the entire line of Micro Essential Lab's Short Range pH test papersThis review is for the 2.9-5.2 version of this product.I bought two packages of this test paper nearly two years ago for testing all sorts of lacto-fermented (kombucha, sauerkraut, lacto-fermented pickles/relish, etc) things and I've still got plenty left on the second roll! Each package contains 2 rolls of the test paper, wrapped in foil. It gets in the ball park figure good enough for my needs. For lacto-ferments, if it's orange (the brighter, the more acidic), it's reached the critical safety zone of acidity for a safe ferment. I have not tested it against a more accurate pH meter, but it does test as lower pH when I use it on something like store-bought vinegar (maxes out at bright orange/2.9) and higher pH if I test a freshly started batch of sauerkraut (it hasn't acidified yet, shows up as same color as the paper, green, at 5.2). These work well and are very inexpensive. No need to calibrate a meter, clean the probes or make sure they're stored properly (just keep it in a normal dry place, out of direct light).The 2.9-5.2 range is one of the shorter ranges MEL sells, which helps makes it a little more accurate.Be sure to use this with dry hands, otherwise you'll end up with a bright blue "temporary tattoo". Also, don't set the wet tested strip on a stainable surface, such as natural fabric or untreated wood.Note that you don't need to test pH to make good lacto-ferments. Smell will usually tell you all you need to know...sour/pickled is good, nasty is not. But I've had a couple ferments be in a gray zone, smell wise. Of course, I could use the "if in doubt, throw it out" rule, but since I had test paper, I was able to confirm the pH and then decide if it was still worth eating.