Do I need a pH Meter?

You need a pH meter if the following circumstances apply:

You produce one of the following types of food:

• Acidified food
• Fermented food
• Low-acid-canned-food
• You use chemicals whose concentrations require testing using a pH meter.
• You produce a product that uses acid or fermentation as a means of preservation.

About pH Meters 

pH meters are designed to measure the acidity or alkalinity of a substance. There is a meter to measure anything from chemicals in a laboratory to soil out in the field, and there is a meter type to suit specific tasks. Models can include, convenient pen meters and handheld devices, right up to professional benchtop meters. No matter the design or use, your pH meter will occasionally need a little tender loving care and maintenance.

Why and How to Maintain a pH Meter

Just like your car, maintenance of a pH meter is essential to keep it in good working shape, and as a bonus, this will generally prolong the life of your device. Your pH electrode will eventually reach the end of its useful life as its performance naturally degrades over time. To maximize the performance of your pH electrode and extend its life span, proper care and regular maintenance are equally required.

Calibration

Regular calibration of your pH meter is essential. The frequency will be determined based on how often you use your device. You can calibrate most pH meters in-house, some pH meters will tell you when they require calibration, and others will not.

If you use your pH meter every day, you should calibrate it daily. If you use it a few times a week, weekly calibration would likely be suitable. For best results, calibrate your meter to a minimum of two points before each use.

Tip: In addition to calibrating to two points, we recommend that you calibrate to two buffers that shoulder your expected sample, this will be neutral pH seven and the second buffer. For example, if your sample is expected to be pH 5.2, you would use pH 7 and pH 4 as your calibration buffers.

Below is a video showing the calibration of a non-glass pH meter used in the Dairy Industry.

Handling

Rinse electrodes with distilled water before and after measuring a sample. Blot the end of the electrode with lint-free paper to remove excess water. NOTE: Never wipe the electrode to remove excess water – wiping can create static charges that interfere with correct pH measurement.

Cleaning

Keeping your electrode clean is an easy way to extend its life. Between measurements rinse the electrode with distilled or deionized water.

A more thorough cleaning will be needed if a coating has started to form over the glass bulb or if the device is performing inconsistently. To do so, place in an electrode cleaning solution for 10-15 minutes then rinse thoroughly with distilled water. Most meters recommend that you do not wipe them down with tissue or cloth, as this can cause static, which could harm the electrode. Check your user manual for device specifics.

After rinsing the electrode, place the device back into its cap with a storage solution. It’s best practice to let it sit in a storage solution for a couple of hours after cleaning.

Storage

Most pH meters require the electrode to remain in a storage solution when not in use.

Why? To keep the bulb of the meter at optimum sensitivity. Sensitivity is affected due to the design as pH electrodes have a hydrated gel layer. This layer facilitates the electrical signal needed to obtain a pH reading. Storing a pH electrode dry will seriously reduce its sensitivity.

If you forget to cap your meter once or twice, it may not be the end of the world (we’ve all been there). The remedy is to soak it in a storage solution for a couple of hours and perform a calibration to ensure it is working correctly before use.

To be sure, check your electrode’s user manual or operational instructions for specific storage medium details.

Electrode Replacement

Tip: Look for a pH meter with a replaceable electrode. Although this is more costly outright, replacing an electrode is cheaper than replacing the whole device.

Unfortunately, not all pH meter users know this, but a pH electrode is generally a consumable item. Depending on your use, we recommend you replace your device’s electrode every 6-24 months. Following the three tips above will reduce the frequency of electrode replacement, but when the time comes there are three main things to look out for which will indicate it may be time to replace an electrode;

1. Difficulty or inability to calibrate the pH meter
2. Unstable, variable, or slow readings; and/or
3. Physical signs of damage or wear and tear.

If you need any information on whether or not your pH meters electrode is replaceable, or need a replacement and aren’t sure where to find it, contact us.

 pH Meter Electrode Lifespan

Why don’t we make an electrode that doesn’t burn out and needs replacing? The answer is that this technology simply doesn’t exist yet. As it stands, there are physical constraints on the system that prohibit the creation of longer-life or permanent electrodes. Current pH electrodes have a lifespan of about one year or up to 18 months at the most (with less frequent use). If you properly care for your electrodes, you’ll still need to replace them roughly annually. That said, there are things you can do to avoid damaging your pH electrodes. They can be fairly fragile and require a little extra TLC, which we’ll discuss below.

Replaceable vs Non-Replaceable Electrode pH Meters

It’s important to understand the differences between replaceable electrode meters and non-replaceable electrode meters. The names of the two groups are self-explanatory, but whether you buy a replaceable electrode meter or not depends on how you intend to use it.

Replaceable electrode pH meters like our High Accuracy pH Meter are great if you have long-term plans for testing pH. Been brewing for a while and you’re planning on keeping at it? You should get a replaceable electrode meter. But if you’re working on a one-time project or aren’t planning on using your meter for longer than a year, just go with a low-cost non-replaceable meter like our Waterproof pH meter.

Either way, you need to be aware that the electrodes in your pH meter are going to wear out. pH meter electrodes are like old-fashioned candescent light bulbs: over time they just ‘burn out,’ no matter how carefully you use them. With non-replaceable electrode meters, it means you’ll need to buy a new meter in about a year’s time. But with replaceable electrode meters, means you’re going to have to buy replacement electrodes to keep your pH meter working long term.

Conclusion

pH meters are fantastic instruments that can help you elevate your brewing, cheesemaking, sushi, or even gardening to the next level. Yes, pH meters have their limitations and maintenance can seem tedious, it will likely save you time and money in the long run. So, if you follow the best practices like keeping your electrode hydrated, using calibrating buffer solutions, and controlling your testing temperature, you’ll get the best possible lifespan from your meter.

You can view our range of pH buffers, cleaning solutions, and storage solutions. If you need more information on any of the above steps or need a hand with your pH meter, contact one of the PMI Sales Team at +27 11 728 6099, being helpful is what we do!