pH testing for pickles and acidified foods
How do I test pH to sell pickles or acidified vegetables under the Arkansas Food Freedom Act?
- Choose one of the three routes: approved recipe, lab-tested recipe, or batch testing
- Buy a pH meter with 0.1 resolution and 0.1 accuracy if you test yourself
- Calibrate the meter before each session with buffer solutions
- Measure the equilibrium pH of the finished, cooled product
- Record 4.6 or less for every batch, with the batch number
- Keep the four required records for each batch
Why pH 4.6 is the line that decides everything
Acidified vegetables are allowed only with an equilibrium pH of 4.6 or less, shown by an approved recipe, a lab-tested recipe, or a calibrated pH meter reading each batch.
The number is not arbitrary. Below pH 4.6, Clostridium botulinum spores cannot grow to produce their toxin, which is why low-acid canned foods above that line cannot be sold homemade at all. The 4.6 threshold is the same one the FDA uses to divide acidified from low-acid foods.
So the state's bargain is exact: prove your acid, or do not sell the jar. The allowed-foods page shows which vegetables are eligible; this page is about the proof itself.
pH 4.6 or lessArkansas Code § 20-57-503 includes acidified vegetables with an equilibrium pH of 4.6 or less as non-TCS food if the recipe is approved, lab-tested, or batch-tested with a calibrated meter. — Arkansas General Assembly (Act 1040 of 2021), retrieved 2026-09-29
The Arkansas Department of Health states low-acid canned foods with a finished equilibrium pH above 4.6 can only be produced under a permit, because botulinum spores survive boiling water. — Arkansas Department of Health, retrieved 2026-09-29
The three routes to a lawful jar
Route one is an ADH-approved recipe. The Department's guide links to tested recipes, most from the National Center for Home Food Preservation, and following one exactly needs no meter.
Route two is a recipe tested by an appropriately certified Food Process Authority, which has confirmed the finished product holds at 4.6 or below. The Association of Food and Drug Officials publishes the directory of authorities.
Route three is testing every batch yourself with a calibrated pH meter. That route is the most work and the most flexible recipes, and it is the one most producers underestimate. Deviating from an approved recipe pushes you onto route two or three immediately, because the tested process no longer describes your jar.
The Arkansas Department of Health requires an ADH-approved recipe, one tested by a certified Food Process Authority, or batch testing by the producer with a calibrated pH meter. — Arkansas Department of Health, retrieved 2026-09-29
The Arkansas Department of Health's guide links tested recipes from the National Center for Home Food Preservation, safe when followed, with deviations requiring further testing before sale. — Arkansas Department of Health, retrieved 2026-09-29
The Arkansas Department of Health requires an ADH-approved recipe, one tested by a certified Food Process Authority, or batch testing by the producer with a calibrated pH meter. — Arkansas Department of Health, retrieved 2026-09-29
Buying and calibrating a meter that counts
The Department sets a floor for the instrument: only pH meters with a resolution of 0.1 pH units and an accuracy of plus or minus 0.1 pH units should be used.
That floor rules out the cheapest strips and indicator papers entirely, and it rules out loose meters. Buy one that displays to one decimal, says its accuracy on the box, and comes with calibration buffer solutions.
Calibrate before each session, following the manufacturer's routine with fresh buffers, and never mid-batch on faith. A meter that has drifted reads 4.5 when the jar is 4.7, and a wrong reading is not a defense; it is the opposite of one.
0.1 pH accuracyThe Arkansas Department of Health states that only pH meters with a resolution of 0.1 pH units and an accuracy of plus or minus 0.1 pH units should be used for batch testing. — Arkansas Department of Health, retrieved 2026-09-29
The University of Arkansas System Division of Agriculture advises producers wanting to measure pH at home to purchase a pH meter or have the pH measured at a certified laboratory. — University of Arkansas System Division of Agriculture (FSPPC318, May 2026), retrieved 2026-09-29
Measuring equilibrium pH the way the rule means it
Equilibrium pH is the pH of the whole finished product after the acid has had time to distribute, not the brine alone and not a hot reading.
Cool the jar fully first. For pickled vegetables, the Department's practice, mirrored in university guidance, is to blend a representative sample of solid and liquid to a uniform puree and measure that, so the reading reflects what the eater consumes.
Record the number, the date and the batch number together. If the reading lands above 4.6, the batch cannot be sold as homemade non-TCS food, whatever the recipe promised. Do not sell it and do not re-label it; the only lawful home for it is your own table.
equilibrium pH 4.6 or lessThe Arkansas Department of Health requires acidified products to have an equilibrium pH of 4.6 or less in the finished product, with each batch labelled with a unique batch number. — Arkansas Department of Health, retrieved 2026-09-29
The Arkansas Department of Health's quick reference requires pH meter testing below 4.6 for acidified foods made without ADH-approved or lab-approved processes. — Arkansas Department of Health, retrieved 2026-09-29
The records that make the route lawful
Batch testing is only lawful with records. For each batch, Arkansas law requires the batch number, the recipe used, the source of the recipe or the measured pH, and the date the batch was prepared.
The Department's guide mirrors the statute word for word, and both mean a notebook that travels with the kitchen, not a reconstruction after a market inspector asks.
Label the jar with its batch number too, so a question about a jar can be answered from the notebook in one lookup. The batch records page gives the full layout and a worked example.
4 record entries per batchArkansas Code § 20-57-503 requires records including the batch number, the recipe used, its source or testing results, and the date the batch was prepared. — Arkansas General Assembly (Act 1040 of 2021), retrieved 2026-09-29
Arkansas Code § 20-57-503 requires records including the batch number, the recipe used, its source or testing results, and the date the batch was prepared. — Arkansas Department of Health, retrieved 2026-09-29
Where Arkansas producers get help
The state built real help into this path, and using it is cheaper than guessing.
The Arkansas Food Innovation Center at the University of Arkansas offers pH testing plus facilities and equipment for commercial production of shelf-stable products in jars and pouches. The AFDO directory lists certified Food Process Authorities beyond the state, and your local health unit's environmental health specialist answers the recipe questions neither can.
Before scaling a pickle line, pay the Arkansas Food Innovation Center or an AFDO-listed authority once to test the process, and you may not need the meter at all. That trade is worth doing the math on in the cost page.
The University of Arkansas Division of Agriculture states the Arkansas Food Innovation Center offers pH testing and facilities for shelf-stable production in jars and pouches. — University of Arkansas System Division of Agriculture (FSPPC318, May 2026), retrieved 2026-09-29
The University of Arkansas Division of Agriculture states the Arkansas Food Innovation Center offers pH testing and facilities for shelf-stable production in jars and pouches. — University of Arkansas System Division of Agriculture (FSPPC318, May 2026), retrieved 2026-09-29
Questions
Can I test pH with paper strips?
No. The Arkansas Department of Health says only meters with a resolution of 0.1 pH units and an accuracy of plus or minus 0.1 pH units should be used. Strips cannot resolve the difference between 4.5 and 4.7, and that difference is the entire rule.
Do I have to test every batch if I use an approved recipe?
No. An ADH-approved recipe or one tested by a certified Food Process Authority carries the batch. Batch testing is the route for recipes that are neither. What you keep either way are the batch records: number, recipe, source and date.
What if my batch reads 4.7?
It cannot be sold as homemade non-TCS food. The equilibrium pH must be 4.6 or less. Keep it, give it away outside a sale, or discard it, and adjust the recipe or the process before the next batch.